Component Identification: Front Calipers: [Editor:] Volvo 700 cars use a variety of calipers, rotors, and pads on the front hubs. Prior to working on the brakes, carefully identify which components you have so that you can acquire the correct parts. [Inquiry:] Does anyone know if there is a way to tell which of the two caliper types (ATE or Girling) my 740 GLE is using without removing the wheels? [Response: Paul Grimshaw] Refer to the product plate (located above passenger front headlight or in the trunk or door jamb). Go to position "E" (end of the second line on the right). The following codes apply:
ATE calipers are ONLY used on rear wheels. Note that DBA is the same as Bendix. The best way to identify front calipers is to look thru the wheel for a large iron bridge that reinforces the caliper body (with a slot on either side i.e. two slots):
Rear Calipers: [Another Inquiry] I'm close to needing rear brake pads on my wife's 90 740. Peeking through the rim, I see the capital letter "A" in sort of an Italic script, followed by a couple more smaller characters that I can't make out, cast onto the caliper. Can anyone tell me what kind of brakes they are, given such weak info? Now the bonus point question....what would the Volvo P/N's be for the pads? (Not that I would necessarily use Volvo pads. [Response: Ted D'Orazio] Your rear calipers are ATE. The p/n for the rear pad set is 271824. [Editor] Note that the rear calipers came with three piston sizes: 36mm, 38mm and 40mm, stamped on the caliper- see the photo. Replace with the identical size. Often the markings are obliterated due to rust or mechanical damage. You can measure the diameter of the piston when the pads are removed or measure the imprint on the back of the steel shim plate. Wagons generally use 40mm pistons. [Inquiry:] When I went to get a set of front disc brake pads for my 740t there were two types listed. Does anyone know which type I would need or how to tell Bendix from Girling? [Response: JohnB] The Bendix pads have two tabs on the outer edge of the backing plate, some versions quite large, about 3/8 in by 3/16 in with a round cylinder welded/brazed on each tab, others with two vestigial nubs....both types come with slightly different anti-vibration springs so don't mix them. The Girling pads have a single big tab with a post on it and the anti-vibration spring wound around the post. Rotor size matters....the 11.25 in rotor works on Girling and Bendix brakes with separate rotor/hub. Make sure you know what hub/rotor you have. Finally, your minimum permissable pad thickness, when you are checking pads, is 3 millimeters per Volvo specs for the front pads and 2 millimeters for the rear. Here is a visual guide to brake pads used in various caliper configurations in 700/900 cars, courtesy of RPR where each pad set can be ordered on-line.
Brake Rotor Identification. [Editor's Notes:] Volvo 700/900 series brakes came in a number of configurations: one-piece hub and rotor versus separate rotor and hub; solid versus ventilated rotors; various calipers for ABS and non-ABS; various rotor diameters and thicknesses. In addition, early 700 series may have been converted to two-piece hub and rotor configurations or to later "jumbo" rotors. Be very careful when replacing the rotors. The only sure test is to measure the diameter and thickness or look for a stamping showing the diameter on the hub and order the corresponding replacement from a knowledgeable parts department. The data in the two tables below are courtesy of VolvoCars and RPR a retailer of Volvo aftermarket parts. Note that they do not mention 10.25 inch diameter rotors which were fitted to a number of Girling-equipped cars. See the type chart for guidance on matching the rotor to the caliper (one or two pistons)
In the following chart, the "Absolute Minimum" thickness is the thickness at which replacement is mandatory. The "Minimum" thickness is used when you replace pads: if the measured rotor thickness at the points of pad contact is less than this number, replace the rotor. Conversion: 262.4mm= 10.5 inches; 280mm= 11 inches; 287mm= 11.25 inches. One inch =25.4mm.
Fluid and Pad Maintenance: [Inquiry] Are there pad wear indicators to tell me when my brake pads are wearing out? [Editor] No! You have to inspect pad wear through the caliper slots to make sure you have adequate pad thickness. Unlike other cars, there is no noisemaker to let you know when you need new pads. And if they wear out? You may score the rotor, which will then need to be replaced. Why Flush Brake Fluid Every Two Years?: Remember that brake fluid absorbs water vapor from the air. This water contributes greatly to poor stopping performance and to the decline of your hydraulic cylinders and brake components. In addition, high brake temperatures accelerate the rate at which the corrosion inhibitors in brake fluid break down. As the fluid ages, oxidation eats away at metal surfaces creating dissolved acids and sludge that are carried with the fluid as it surges back and forth with every application of the brakes. The contaminants are abrasive and increase seal, piston and bore wear in the calipers, wheel cylinders and master cylinder. They can also attack and damage ABS solenoid valves and cause these valves to jam and stick. For these reasons, Volvo recommends that you flush hydraulic systems every two years. This is most important for your brakes' hydraulic system. [Editor's Note: See Brake Fluid Flushing Procedures below for complete instructions. See http://www.phxsyss.com/ for information on "StripDip" brake fluid test strips. ] Which Fluid Should I Use? [Inquiry:] My friendly Volvo parts person says that my Volvo needs DOT 4+ brake fluid. Of course dealers use Volvo-labeled fluid. Is this equivalent to Castrol GTLMA which "Exceeds DOT 3 and DOT 4 specifications"? [Response: Bob] The Castrol fluid is fine as long as it meets DOT 4. Use a pressure bleeder for most effective flushing. [Editor: See Brake Fluid Comparison for more information.] Silicone DOT 5 Fluid Acceptable? Absolutely NOT: under no circumstances add or use in any way DOT 5 silicone-based fluids, which are completely incompatible with the materials used in Volvo brake systems. However, the new DOT 5.1 glycol fluids are fully compatible with your system. Brake Fluid Flushing Procedures. [Digested from the Volvo Manual] Flush the fluid in your braking system at least once every two years to remove water and contaminants. The manual notes that you should de-pressurize the pressure flusher after doing each wheel, then operate the brake pedal several times, before going to the next wheel. Master Cylinder Reservoir:
Rear Wheels: Remove or press back pads on one rear wheel. [Editor's Note: Clamp off brake rubber line and open bleed screw on ABS-equipped cars so you don't force contaminated fluid back to the ABS unit. See Brake Job Tips: Hose Clamp.]
Front Wheels: [Cars with Girling Single-Piston Calipers:]
[Cars with Bendix and Girling Two-Piston Calipers:]
After doing all four wheels, operate the brake pedal several times. Pedal travel after 3-4 depressions (as if braking very hard), with the ignition off, should not exceed 55 mm for older cars and 50 mm for 1995 and up 900 series (all 960 and mid-year+ 940: see Service Bulletin 5-51-908 Jun 95) Need to Flush Before Replacing Components. [From RPR:] When changing components that use brake or clutch fluid, be sure to use the proper fluid (usually DOT 4 brake fluid for Volvos). It is also necessary to flush the lines before installing slave cylinders, calipers etc. Many people simply pull the old unit off and then "slap" the replacement unit on which causes any old fluid or contaminants to damage the replacement when the lines are bled. Our experience with clutch slave cylinders went from a return rate of approximately 50% to less than 5% by simply advising installers to follow these simple instructions. Basic Brake Bleeding Procedure. [Tip from Abe Crombie] All you need do is obtain a piece of 1/4" I. D. clear vinyl tubing and a coke bottle. Have 2-3 pints of the proper brake fluid on hand. IF you are changing a part and air is already in system, then the order is important. IF you are doing a flush/bleed then the order is not important. Remove the master cylinder reservoir and dump it out and add a bit of fluid and agitiate it and dump it out to get all the old fluid out. Install resevoir and then fill with fluid. Go to whichever caliper you care to do first and loosen the bleeder 1/8 turn. Attach the clear tubing and place end in coke bottle. Add just enouigh clean brake fluid to coke bottle so that tube is below the fluid level. Get in car and pump pedal slowly about 1-1/2 inches 10 times. Don't exceed this extension or you will press the master cyclinder seals into corroded areas within the master cylinder and ruin them. Get out and check/top up fluid. See if the fluid in tube is clear, if so close bleeder and remove tube. If not, pump five more times. Go to next caliper and repeat until all have been done. The bleeder screw opening should be just enough to allow fluid to pass out. This can be determined by feeling resistance as you push pedal. If the pedal goes to floor w/o resistance then you should turn in bleeder screw 1/16 turn. The idea is to do have resistance to the master cylinder suction pulling fluid back in through tube. This way the fluid will be pulled from reservoir on upstroke of pedal and you will not need to do the pump x times, hold, open screw, close screw, pump x times thing. I have done this for 25 years and never had a problem and never had arguments with girlfriends, co-workers, family members as I didn't need their assistance. IF you have a buch of air in system then you will have to do the pump-open-close pump routine. For ABS-equipped cars, see the notes on Brake Fluid Bleeding/Flushing Procedures for Cars with ABS. If you have lots of air in the lines and master cylinder, tap them as you bleed to loosen adhered air bubbles. Brake Bleeding Sequences. [Editor's Note: These sequences apply to all cars per the Volvo manual]
[Inquiry:] I've never bled calipers that had TWO bleeder valves --- What is the bleeding order? Is is special for the 740 wagon? It is a 91 and it has ATE on the rear, no problem, but dual Girling calipers (?) vented rotors on the front w/ two bleeders ea. The Chilton manual is not helpful with the dual system. I can't find any other repair manual for the 740. [Response: Steve Seekins] An interesting dilemma - the manuals vary on the correct bleed sequence. According to some, when you have an inner and outer bleed screw on a caliper, you should bleed the outer first, then the inner, however, my engineering sense would tell me to do the inner (closest to the MC first, then the outer. That way no old fluid or air would get into the outer after bleeding it. In any event, I suspect that it is not critical, and I always recommend going around twice - first time until all air/old fluid is out of system, second time to check for any air. Expect to take about 1.5 quarts for a complete system flush. On the non- [Editor's Note: when bleeding, use the uppermost nipple to expel any air. When flushing fluid, use the lower nipple, then close and check the upper nipple for any trapped air. See Brake Fluid Flushing Procedures] ABS-Equipped Cars: See Brake Fluid Bleeding/Flushing Procedures for Cars with ABS Rusted Bleed Screws: Tips for Removal. [Tip from iadr/Cliff Pope] Here is a tip that's saved me a couple times when removing screws that the P.O. has not thought to lubricate- take a small ball peen hammer and give the bleeder screws the hardest hit you can without mushrooming the tip where the fluid comes out. To clarify, pretend you are diving them into the hole they are threaded into: don't hit them sideways. This seems to loosen the rust on the threads. Once you get it moving even a fraction, you have done it. Move it cautiously back and fro, until it will screw freely. Needless to say, try using PBlaster penetrant and a good six-point socket before going to extremes. Just be aware that too much torque can break off the hollow screw. If you snap it off you are in real trouble. I have never succeeded in extracting a broken one, so you will need a new caliper. ] [More Tips from Motor Magazine] Penetrating oil has a better chance of being effective in loosening a seized bleeder if you wire-brush rust/scale away from the caliper's bleeder bore before applying it. Be sparing, though. You don't want petroleum-based penetrants contaminating brake fluid. Also, filling the bore in the bleeder itself with a snug-fitting drill bit helps reinforce the bleeder against twisting forces as you try to unscrew it. We don't recommend heating the caliper casting with your torch to loosen seized bleeders; the heat may not just boil away brake fluid, it may damage seals or boots. Keeping the bleeder capped definitely helps prevent seizing; vacuum caps often make acceptable substitutes if actual bleeder caps are unavailable. Master Cylinder Bleeding. If you need to bench bleed a rebuilt master cylinder, see Rob Bareiss' simple bench bleeder tool made from lengths of brake line. A pressure bleeder works by pushing fluid into the reservoir at pressure to force the old fluid out the caliper nipples rather than suck it out from the nipples. Brake systems are pressure systems and are better able to deal with even this small pressure than a vacuum system which will always suck a little bit of air in at the nipple. These pressure bleeders are inexpensive and make brake system fluid maintenance very easy. 1. Motive Products Power-Bleeder Brake Pressure Bleeder: [Tip from Steve Seekins] I recently received, tested, and reviewed a new product - 2. Gunson Eezi-bleed Brake Pressure Bleeder: [Comment:] For those outside North American, one can buy a Gunson's EEzi-bleed. Eezibleed works great - I have found that 25 psi works [Editor] The MityVac vacuum (not pressure) bleeder works, but you have to use care to ensure that air bubbles are not sucked in around the bleed screw nipple. [Tip from Mike] I've used a MityVac a couple of times to bleed my brakes. It's very time consuming (about 2 hr.) and a bit messy if you are not careful. Also, your hand will get a workout squeezing the damn thing. Be sure you have the proper sized nipple to fit over your bleeder screws or it will take you more time. And don't let your brake resevoir get below 3/4 full during the bleeding process. If you start to suck air, you of course have to start over and you may have to bleed the reservoir as well. [Tip from Dan] Use the hose on the bleed screws to avoid air bubbles. 4. Home-Made Pressure Bleeders. [TV Pierce] You can make your own pressure bleeder. Power Motive's is nothing more than a garden sprayer with a brake reservoir cap attached to the end of the tube instead of a spray nozzle (they also add a pressure guage -- but it's not really necessary). The sprayer is about $10 at Home Depot, and a new reservoir cap should be $2-$3 at FCP Groton. Drill a hole through the cap, epoxy a tube fitting through the hole, then cut off the spray nozzle, and attach the reservoir cap. [Gary Gilliam] I made mine out of a cheap all plastic 4 liter ( about $13) garden sprayer, and an old master cap. I cut the hose just above the sprayer wand, attached a 5/16" brass fitting that is commonly used for repairing air lines: it is barbed on one end to stick inside the hose and has 1/4" NPT threads on the other. This was secured to the hose with a stainless hose clamp and a 1/2" hole was drilled in the extra master cylinder cap to receive the other end of the fitting. The fitting was secured to the cap with a 1/2" long brass NPT straight connector, adding a rubber washer on both sides coated in RTV for good measure. Pad Replacement: Pad Selection. What I've found over years and years of experimentation with different types of brakes ranging from soft OEM pads to full-on race pads is that there is NO SUCH THING as a completely dustless pad. Generally speaking however, the harder the compound, the less dust per mile accumulated on your wheels. Organic compounds (particularly older asbestos based pads) are about the worst. The Axcess nee PBR nee Repco pads are better than stock but the organic versions still have more dust accumulation than the Metalmasters. Of course, you get a significant increase in braking performance with these so what's a little dust when you can stop in 15% (guesstimate) less distance. Might save one's life one day.On that note, someone mentioned a tradeoff using metallic pads versus softer OEM type pads and their relative effect on rotors (wear). In my type of driving (90%+ freeway), I'm not on the brakes much which owes to my getting 90k+ miles per set AND original rotors after 221k miles. If you are driving more stop/go type traffic scenarios, there will be some additional wear on the rotors but not so much as to worry. (Either way, you're going to replace them anyhow...) [TechTip from C. Smith of Stoptech] There is no such thing as an ideal "all around" brake pad. The friction material that is quiet and functions well at relatively low temperatures around town will not stop the car that is driven hard. If you attempt to drive many cars hard with the OEM pads, you will experience fluid boiling, pad fade and friction material transfer - end of discussion. The true racing pad, used under normal conditions will be noisy and will not work well at low temperatures around town. Uneven Pad Wear. [Tech Tip from Wagner Brake] While inspecting for excessive pedal travel, brake linings appear worn in a tapered pattern, even though the pads have not reached minimum thickness. SOLUTION: Uneven pad wear is not normally related to excessive pedal travel, but it's not unusual to discover one problem while investigating another. Linings with tapered, uneven wear should be replaced if the difference in thickness from one end of the pad to the other 1/8 inch on floating calipers. This remains true even if the linings have not reached minimum thickness because this condition can result in pads becoming wedged in the caliper. If the pad that contacts the caliper piston is worn much more than the one on the other side of the rotor, something is interfering with the necessary sideways movement of the caliper. This may be corrosion, contamination, or improper assembly. Possible causes of excessive pedal travel are low fluid level in the reservoir, air in the hydraulic system, an open bleeder screw (avoid the use of Teflon tapes or pipe thread sealants which do not help seal and may cause contamination), improperly positioned pads, ., piston seal damage in one or more of the calipers, a leak past the piston cups in the master cylinder, excessive rotor runout or a bent rotor and bad or excessively loose wheel bearings. Pad Break-In. [Tech Tip from C. Smith of Stoptech] Follow proper break in procedures for both pad and disc. All after market discs and pads should come with both installation and break in instructions. The procedures are very similar between manufacturers. With respect to the pads, the bonding resins must be burned off relatively slowly to avoid both fade and uneven deposits. The procedure is several decelerations with a brief cooling period between them. After the last stop, the system should be allowed to cool to ambient temperature:
Rear Brake Pad Replacement: [Tips from Andre] Changing the rear pads on ANY Volvo since the 70's is pretty much identical. You will need a hammer and a long narrow punch (a large dull nail works in a pinch). To Remove:
To Install:
Front Brake Pad Replacement. [Tips from Andre] To Remove:
To Install:
Brake Lubricants: [Tip from Brake and Front End Magazine, Nov 01] Use a synthetic moly or PAO-based lubricant for metal-to-metal contact points and a synthetic silicone brake lube for caliper assembly with rubber parts. Do not use white lithium or chassis grease in brake work. In disc brakes, lubrication points include the caliper slides and bushings, self-adjuster mechanisms on rear disc brakes with locking calipers, and the parking brake cables and linkage. Brake grease can also be used to dampen vibrations between disc brake pads and caliper pistons. But, it should not be applied between the pad and any noise suppression shims that may be used. Use it on the back of a bare pad or between the pad shim and caliper. One place you never, ever want to get any grease on is the friction surface of a brake lining - which is another reason for not using low-temperature or petroleum-based lubricants which can melt, run off and foul the linings. Grease-contaminated shoes or pads will be grabby and usually cause a brake pull to one side. The only cure is to replace the fouled linings with new ones. Cleaning is out of the question because solvents and cleaners can adversely affect the linings, too. [Fitz Fitzgerald] The brake lube is intended to be used at every point where the brake pad contacts another metal part,except the rotor:
Additional Replacement Tips: [Inquiry:] Any hints on front/rear brake pad replacement? [Response:] Be sure to remove the sliding pins on both front calipers. Inspect them and replace if worn or badly rust pitted. Otherwise, clean them, grease with silicone based brake grease, and reinstall. Clean caliper sliding surfaces with small wire brush and blow clean (use a mask!!). Check to see if new pads are beveled on leading and trailing edges. If not, consider putting a 45 degree bevel on them. Use the brake grease on the backing plate, the anti-squeal plate and the edges of the backing plate that contact the caliper. Install the pads carefully so that the anti-rattle springs do not get broken (the springs on the new REPCO pads are much heavier than the earlier pads, so should not break like they did before). I prefer the plain stainless backing plates rather than the black rubber coated ones. The rubber, though it may be thin simply adds a bit of softness to the pedal feel, as does any of the 'rubbery' anti-squeal treatments. I have found that just using the Volvo brake grease seems to solve the squeal problem as long as you clean rust off the caliper contact and sliding surfaces. The backing plates should have some slots or holes in them - creates a slightly of center contact surface for the pistons which apparently helps prevent squeal. If you are replacing the rotors, clean the protective oil coating off the new ones with brake cleaner so you do not contaminate the pads. And remember that when you first get in the car after replacing pads, you will have to pump the brake pedal several times (not all the way down: just an inch or so) to move the caliper pistons back into position. Brake Squeal.[Brake and Front End Magazine, Aug 04] Brake squeal is caused by high frequency vibrations. When the brakes are applied and the pads contact the rotors, tiny surface irregularities in the rotors act like speed bumps causing the pads to jump and skip as they scrape against the rotors. This, in turn, causes the pads to shake and vibrate in the calipers and against the caliper pistons. It also causes the calipers to shake and vibrate on their mounts and bushings. The greater the play between all of these parts, the greater the amplitude of the vibrations and the louder the squeal. [Tips from Raybestos to eliminate brake squeal. These tips are generic and not specific to Volvo.]
hile these procedures will not guarantee against a noise-related comeback, they will reduce the odds significantly. Moreover, these methods have been developed in the field by brake technicians and approved by others using the same techniques. Brake Pad Anti-Squeal: Pastes and Shims. Brake Pad Anti-Squeal Treatments. [Inquiry:] What's your experience regarding brake pad anti-squeal treatments? I've looked at the following
Shims. [Response: Don Foster] Try using the stainless shims (available from Volvo) behind the pads. Also, there are Teflon sheets (also from Volvo) you can insert between the stainless shim and the pad metal backing. Be sure the piston bears against metal.If you're truly climbing-the-walls desperate, there's some "goop" you can put on the back of the pads to dampen vibration (squealing). I've used it, it works, it's messy. But the shims are better (but from Volvo, not too cheap). [Response: Benjamin ] I too, tried the Lucas foil backings, with no success at all. What finally worked on my Slaab was some cheap rubber-like adhesive shims from NAPA. They cost about $3 per wheel, and stuck to the back of the pad like the Lucas foils, however these were rubber, and work great. This is the only thing I've tried that works. I tried the Lucas foils on my MetalMasters when I got them from SAS, with no results. I then put these rubbers ones on the MM's, and presto, the first squeal-free Saab I've had in over 7 years of owning different Slaabs. Caution: Aftermarket Pad Shims.[Editor] Several anecdotes have been received about Beck Arnley pad shims, which can come loose and score a groove in the rotor which may lead to rotor and wheel failure. If you use stick-on shims, make absolutely certain the pad backs are clean of grease before installing the shims: spray them first with brake cleaner. Loose shims need to be carefully installed in the calipers before finishing the job so they cannot migrate loose. Consider using paste or grease instead of a shim or stay with the Volvo OEM version. Synthetic Grease. [Response: Phil] For squeaky brakes get some synthetic brake lubricant or Dow Corning compound 111...it's a heavy silicone grease...real heavy and tacky...melts at 500 degrees F. Put a layer of this on the back of the pads. It won't wash off and they'll never squeak again. Don't get any on the pad braking surfaces or you may not squeak again either. Lubricating the caliper mounts, shims and bushings is also recommended to dampen vibrations here. The lubricant acts as a cushion to dampen vibrations. It also helps the parts slide smoothly so the pads wear evenly (uneven pad wear is a classic symptom of a floating caliper that is sticking and not centering itself over the rotor). How to apply grease: use a visible film of brake caliper lube on all pins and other contact surfaces (yes, even ss shims coated with nylon, etc.), both sides of the shims, and the backs of the pads in contact with the pistons. Don't worry about the stray dab on the pistons' outer edges, just make sure the grooves on the clips on either Girling or ATE calipers in which the pads slide are in place and properly lubricated. Your brakes should be fairly quiet Anti-Squeel Paste. [Response: Ceferino Lamb] For anti-squeal, for about 10 years now I've used that thick orange or red anti-squeal goo in the squeeze bottle. I've had no brake squeals since 86, when I sold the Pig-0-Steel (Nissan 280ZX), so the goo seems to work well, and is universally applicable. I always change my own pads and disks. You can buy it at almost any large auto parts shop (Pep Boys, Grand Auto, Kragen, etc), under several brand names. [Tom Francis] The secret of using this stuff is letting it dry for about an hour before the pads are installed. Change the Pads. Semi-metallic pads and those with a high metallic content tend to be more noisy than low-metallic pads or those with little or no steel or iron content. The best results are usually obtained by installing premium pads. Most premium pads also have chamfers and slots to reduce noise. [Adam] Try removing the pads and chamfering the all of the edges as well as removing any accumulated dust. A Dremel works well. Rotors: Brake Rotor Replacement Front Brake Rotor Replacement. Does the Brake Rotor Need Replacement? I have just replaced the front pads on my 740. When I was changing out the pads I noticed that the rotors had a lip around the outer edge. The metal sticks out approx. 1/16 inch beyond the rest of the rotor. This is the area above where the pads normally contact the rotor. The rotors do not seem to be warped. Should grind this outer edge off so that the entire rotor is of uniform thickness? Does this mean that the rotors are worn down too much and therefore I need to replace them? My new pads seem like they are too loose in the calipers. [Suggestions:] Regarding the lip, you don't really need to worry about this, unless the pads are riding on the lip. But, it sounds like it's time for new discs. If memory serves me right, new thickness of a ventilated disc is 22mm, min thickness is 20mm (for a solid disc this is 14 and 11.5mm, respectively) so if you have 1/16 inch lip on each side, that's 1/8 which is 3mm, so that'd put you at 19mm. How much can only be determined by measuring them with a micrometer and comparing measurements with minimum standards. Replacing the Rotors. Changing the rotors is very easy. With wheel off, remove the caliper (2 -13mm bolts) and hang it up with a wire so it does not strain the brake hoses. Then remove the caliper mounting bracket by removing the two 10mm allen or Torx-style bolts. If the latter, use a 3/8 drive or larger socket as they tend to be difficult to turn. Unscrew the wheel locator index pin. Whack the rotor a few times with a mallet to loosen it and pull off rotor. [Tom Irwin] Hit the hubs with a wire cup brush chucked in a drill motor, cleaning off all corrosion everywhere the rotor mates with the hub. To avoid mismatch and subsequent vibration, the hubs must be shiny clean EVERYWHERE that the rotors touch, even around the wheel studs. Wipe the new rotor with solvent-based brake cleaner to remove its protective oil coating, Then replace the rotor, the caliper mount, and the caliper. When reinstalling the wheel, see Anti-Corrosion Advice for tips on preventing stuck wheel bolts and wheels. [Editor] While the manual suggests that you use new brake caliper mounting bolts, general consensus is that this is unnecessary. They can sometimes stretch causing them to come into contact with the inboard rotor surface. For peace of mind, use Loctite on the bolts when reinstalling. Brake Rotor Identification. [Tip from Larry Jacobson] When I bought front disks for my '91 744T the Volvo dealer said there are three disks that are stock on that car and they all look the same. The only surefire way to get the right disk is to tell them the *exact* diameter and then they can match the part. When disks are bought from an aftermarket source it's a crapshoot unless you haul in the old part and carefully compare it to the new part. Brake Rotor Balance. [Editor] See the note below to match the balance lines on rotor and hub and minimize runout. Brake Rotors: Premium versus Economy. [Tips from Counterman Magazine, August 2001] What's the difference between "economy" rotors and "premium" rotors? Besides price, there are also differences in rotor quality, performance, fit and finish. Premium rotors typically follow the design of OEM rotors because rotors are engineered to meet certain noise, cooling, friction and performance characteristics. If a replacement rotor does not meet the OEM criteria, it may take the brake system out of compliance with FMVSS105 or FMVSS135 government safety standards Economy rotors may not meet these requirements and may decrease braking effectiveness and increase pad wear. Because of this, some suppliers of premium rotors now "certify" their rotors as meeting all OEM requirements. One reason for these differences is the metallurgy of the rotors. Economy rotors are typically made in a less controlled environment, which results in poorer grain structure in the casting. This, in turn, affects the hardness of the metal, pad wear and noise. Economy rotors may also contain unwanted impurities, which can form hard spots, pits and pores in the casting. Premium rotors, by comparison, are made using higher quality control standards. This results in better castings with consistent strength and hardness. Another difference between economy and premium rotors is that the former may not use the same number of cooling fins or a different configuration. This may reduce cooling and increase the risk of pedal fade under hard use. Surface finish is another difference that's hard to see, but affects pad break-in and stopping performance. If a rotor does not meet OEM requirements for surface finish, it should be resurfaced before it is installed. This shortens the life of the rotor and increases the risk of installer error or a comeback if the rotor is not turned properly. Dimensional accuracy is also critical. This applies not only to rotor runout and thickness variation (which can cause pedal vibrations, shudder and comebacks) but also all machined surfaces including the size, location and centering of the hub opening, the lug holes and the overall diameter and thickness of the rotor. [Tips from Brake and Front End Magazine, Apr 2003] We have very good results installing slotted front rotors as well as a cross-drilled style, as the factory doesn't offer a heavy-duty rotor. The slotted rotors that we use undergo a factory three-stage heating process that prevents warpage. They cost a few more dollars than other brands, but they are well worth it when comebacks for this problem become history. [Note from Tom Irwin] There is some evidence that Volvo OEM brake rotors for 960/90 cars are of lesser quality; buy aftermarket for better quality and lower prices from reputable suppliers such as IPS, FCP, IPD, RPR. ABS Sensors. Do NOT remove or adjust the ABS sensors while changing pads or rotors. See Brake Rotor Removal on 740 with ABS . But DO clean them and the behind-the-rotor reluctor wheels off with a soft brush. One-Part Hub/Rotor Versus Two-Part. In 1988, Volvo changed the front brakes from an integral one-part hub and rotor to a separate two-part hub/rotor system. In changing rotors while looking at a Haynes manual it's easy to get screwed up on the later two part hub/rotor. The manual suggest that there may be some problems removing these and that a puller may be necessary. No puller is necessary (just use a mallet on the back of the old rotor. You do have to remove the caliper holding bracket...remove the calipers and hang them with a piece of coathanger wire out of the way. Use a long bar and socket wrench to remove the two bolts that hold the caliper bracket on. Put them back with proper torque and blue loctite. You DON'T need to use new bolts unless the bolts won't torque up. Remove the conical wheel locating pin: it holds the rotor on. Make sure the new rotor and the hub/rotor mounting surface are clean when you put the new rotor back on. Rear Brake Rotor Replacement. [Tip] Because the parking brake drum shoes are inside the rear brake rotor, make sure the handbrake is NOT applied when trying to remove the rear rotors. Corrosion can cement these in place so be prepared to knock them off. See below. [Inquiry:] I need advice on removing a rear brake disc that rusted solid on its hub. The parking brake is off, and I am able to manually rotate the disc, so I know its not the drum brake holding it. More than a few whacks with a mallet didn't help. I've sprayed penetrant wherever I could. [Response:]
2. If you DO plan on changing the rotors:
Just try not to have any part of your body under the rotor when it pops off (usually you can tell it's about to go). Editor's note: use a thin coat of anti-seize on mating surfaces between hub and rotor to easy later disassembly Brake Rotor Installation Techniques to Minimize Pulsation. [Editor's Note] Per the Volvo manual, match the balance mark on the rotor (a short line at one spot on the hub portion of the rotor) with the balance mark on the hub, a short line on the shoulder of the hub bearing cover. Look closely through the rust: it's there! This matches the rotor and hub and minimizes runout. Make sure you have removed all rust from the portion of the hub that contacts the rotor. [Tech Tip from Wagner Brake] If the balance lines are not present or are invisible when replacing or removing the rotor, refer to the following service procedure to minimizes hub/rotor "stacked"] runout:
Make sure you reinstall the wheel lug nuts with proper torque values. [Editor's Note:] If your brake rotors continue to warp even after careful installation, then almost certainly you've got a sticking caliper or caliper guide pin. These can cause the pads to rest against the rotor, overheating and warping it. To isolate warping to a specific wheel,the easiest and most effective method is to use a brake hose clamp device on each brake hose. If the condition disappears when the hose is clamped, examine the wheel for a cause. These clamps are commercially available from several tool manufacturers and are specially designed for this purpose. They are similar to vise grips, but are much friendlier to the hose. Be aware that higher brake pressures can push through the clamp and trap pressure in the brake. The brakes will quickly overheat, so keep your tests short. Should I Turn My Rotors? Volvo does not support or advise re-machining of brake rotors, ever. If you look at the machines most shops use to do this work they decide where to clamp the rotor down by eye-ball. When it goes back on the car it is usually worse than when you started. And when you get new rotors - DO NOT let anyone turn them before installation in order to "true them up". They are new, and in the best condition they will ever be in. Don't let anyone screw them up before you ever use them. If your turned rotors are pulsating, I suggest you throw them away and start over with a new set. Wheel Torque and Warped Rotors. Volvo rotors will warp like crazy if the wheel nuts are over-tightened and/or not tightened evenly. If you see someone use an air wrench on your lug nuts when installing your wheels - warped rotors are just a few miles away. Our 1988 760 has gone through several sets of rotors. The problem has been solved since I now insist on a torque wrench being used after the lug nuts are hand tightened. Current rotors have over 40,000 miles and are living well. When you have work done at a tire shop they are there to do what you need done, not what is the fastest for them. Let them use the air tools on someone else's car. Front Calipers: Caliper Guide Pins: Maintenance Guide Pin Discussion. In the Girling front brakes there is a retainer cage that fastens to two "ears" on the axle assembly. There are 2 hex socket bolts that hold this retainer on. At the back of the retainer are two sockets that each receive a floating locating pin encased by a rubber sleeve. The caliper is bolted to these pins so that it is free to move sideways a centimeter or so. The pins have to be lubricated and free to move. In my case one of these pins on each side was frozen and not moving. Thus when the brakes were applied the pistons were able to push the inside pad out but the caliper was not able to move in and pull the outer pad into firm contact. This caused noise and pulsing. [Tip] The front caliper is held by two floating guide pins which move within a bushing fitted into the caliper. Often this bushing shows corrosion and the pin can not be moved within the caliper. If so, the brake performance decreases as the two calipers cannot press the disc properly. To inspect the functioning of the brakes: remove the guide pin bolts and pull the caliper up and away from the guide pins. You should be able to easily move the guide pins in and out. If not, the pin or bushing is corroded or in need of lubricant. Removing Caliper Guide Pins. [Tip from John B] On Girling it's pretty straightforward: remove the fixing bolt, pry the collar on the rubber boot from the caliper and then the boot and the guide pin should come out. Lube the new pin with synthetic brake grease and insert it, put the new boot over the lip and press the collar on so that the ridge on the rubber collar fits in the recess on the pin. On Bendix, it's a little more difficult, you have to ensure the ridges on the boot inside mesh up with the indent on the boot mounting ridge. [Tip from Randy] Unless they are seized the guide pins simply slide in and out after removing the brake pad. If they are seized a good soaking with Aerokroil (or your favorite penetrating liquid) along with the application of the correctly sized socket to add torque and a hammer to add vibration will help. Clean the hole thoroughly and apply an anti seize compound before assembly. I actually sprayed a lot of Kroil into the boot and let it soak. The best aid in having penetrating fluid work is TIME- as in long soak time. [Chris Herbst] One effective way to free the pin is to turn it back and forth while trying to extract it. It's not the easiest thing to do, and if it doesn't work, you are going to be in the market for a caliper carrier, which is not expensive. Lubricant Recommendations. [Tip from Motor Magazine] Most brake lubricants suitable for use today are silicone-based; petroleum-based lubes may cause some newer rubber components to swell. [Editor] Use a brake lubricant specifically made for use on the guide pins; most will say "synthetic" or "silicone". Replace any torn rubber covers. Check the operation and lubrication of the guide pins at each pad change. Rebuild Kit. Volvo has available a repair kit for the lower caliper guide. Cost for the Bendix version is approximately $30 US. Repairing the damaged caliper guide with a kit may be preferable in some circumstances for some owners. The heart of the rebuild kit is a new guide pin with a different design from the old one. Actually, there are two guide pin rebuild kits: one for the lower guide pin only, and one for both upper and lower. The lower guide pin is the one that is most often jammed. To determine whether either of the guide pins are jammed, remove the wheel and brake pads, and pivot up the caliper. The caliper should move freely and easily back and forth on the upper guide pin. The lower guide pin should easily move in and out. If a guide pin is stick in position, it needs to be repaired or replaced. Since the rebuild kit for the lower guide pin is only around $25, I recommend it. Guide Pin Bore Maintenance. [John Sargent] To remove light corrosion from the caliper guide pin bores, use a 10mm rifle or .410 gauge shotgun bore cleaning brush in a drill to clean them. When replacing the pins, lubricate with the high temperature silicone brake grease noted above and make sure the rubber boots are in good condition. Caliper Guide Pin Troubleshooting: Pulling Brakes or Uneven Wear: Caliper Guide Pin Wear or Corrosion . [Symptom 1: My 740 '86 had just turned 100K mi. but it seems to me that every time I step on the brake the car pulls towards the right.] [Symptom 2: Abnormal or unequal pad or rotor wear.] [Diagnosis 1:] It turned out that the caliper slide pin was stuck. The left disk got very hot, because the outer brake pad was constantly pressing the disk and that's why the left front brake was more effective than the right one (because the disk and pads were cold). Also the outer pad wears faster than the inner pad if you have this problem. I simply sanded the rust off the slide pin bore so that the slide pin moved easily and then lubed the slide pin and reassembled the caliper. It might also be a stuck brake piston. So check the pistons, they should move quite easily. I have also rebuilt all four calipers because some pistons were stuck. In my case the pistons were in excellent shape, but the bores in the calipers were not. So I just removed the rust from the bores and rebuilt the calipers with new gaskets and dust boots. [Diagnosis 2:] Your problem might be the same as on my '87 745: the guide pins on your calipers may have worn or corroded, which causes them to grab the pads and hold them against the rotors. Voila, premature pad and rotor wear, as well as poor acceleration and gas mileage. The guide pins are a fairly inexpensive fix, and the difference on my wagon was attention-getting. [Diagnostic Note:] I have found that a damaged lower guide pin is easily detected. One may not need to completely reassemble the caliper to perform the check. If the guide pin is badly damaged, as mine was, the lower guide will be frozen in place with no in/out play. You can remove the bushing from the caliper carrier by pushing with an appropriate tool (a 13mm socket). Lots of force may be required if this bushing has not been removed for long time. Clean bushing AND inside caliper with fine sandpaper or a rifle cleaning brush. Put copper grease on the bushing and slide the bushing inside the caliper. This should be possible without force. Make sure the bushing allows the pin to slide freely and is not too loose. Mount the caliper without the brake pads, and check if the unit slides easily left and right. (Lower bolt to be fixed). Re-mount the brake pads. Mount the wheel and spin it around. Put some Locktite on the thread of the lower bolt and tighten the bolt to 25 ft-lbs. [Assembly note: A common cause of damage to the lower caliper guide pin is over-torquing the guide pin bolt, common when replacing brake pads.] [Diagnostic Note:] If you have a problem with uneven side-to-side pad wear or an intermittent brake pull, in many cases the problem can be detected by using an infrared pyrometer or “heat gun” type thermometer to test relative brake temperatures. To perform this test, apply the brakes at 30-50 mph at least a half-dozen times. After parking in a safe area, check the temperature of the brake rotors with the infrared temperature tester to see if each axle set displays essentially equal temperature readings. Obviously, if the side-to-side axle set temperature readings differ by at least 20%, then a problem exists with the calipers, brake hydraulics or brake pads. See also the discussion of caliper binding and brake hose deterioration. Pulsing Brakes: Caliper Pins Seized . [Report: Don Willson] Pulsing brakes fixed. 1989 765T with ABS and 135,000 miles. I have not seen this solution discussed though there has been plenty of comment on the problem and other remedies. The symptoms were a pulsing of the brakes when light pressure was applied. I thought that it might be the over tightened wheel bolts or a warped rotor. So I jacked up the front and started investigating. Yes the wheel bolts were too tight but the rotor was true, they had been turned last June. What I found was a retainer locating pin was frozen in place. In replacing pads about 4 times on my wife's 744 or my previous 745 I had never realized that there might be other problems though if it had been a snake I'd have been bit. One locating pin was free to move, I could push it in and the grease seal bellows would push it back out. However the other was stuck. With about a half of an hour of twisting and prying I was able to remove the pin without damaging the retainer though the pin was trash. At Volvo I found that you can only by a kit, 4 pins, 4 bellows, 4 caliper holding bolts and a tube of grease for $98. I objected but bought the kit. Reassembly was simple though I did clean out the pin sockets and polish the inner diameters with Scotchbrite on a stick on a hand drill, or use a cheap brass rifle cleaning brush. Reassembly was simple with a liberal supply of grease and properly fitting the bellows. Then locating the brake pads and slipping the caliper over the pads and fastening the caliper bolts to the locating pins. Since these pins are free to rotate a thin 13mm open end wrench comes in handy to restrain the pin while tightening the caliper bolts. Since I had the pins I decided to check the other side. I was not so fortunate, one pin was stuck so hard it twisted off and I had to get a replacement retainer, $10. My recommendation is that when replacing pads and or disks you check both retainers by pushing them to the outside of the car. If they do not move freely remove the retainer (2 hex socket bolts) and get to a vise where you can work the pins out. Replace the pins and bellows. Even if the retainer moves smoothly it might not be a bad idea to remove the pins, careful not do damage the bellows, clean the socket of old grease and any water and relube the pins. I suspect the grease is a silicone as it is water white (about like KY). [Editor] See the notes under Caliper Corrosion and Brake Hose Deterioration for similar symptoms caused by deteriorating rubber hoses. Brake Calipers Rattle: Guide Pin Wear. [Discussion from Dave Stevens] The primary problem area with worn 700/900 front calipers is the sliding caliper guides. Most often the problem will be worn guide pins and/or guide pin sleeves (inserts), particularly the sleeves and most particularly the lower ones. Sometimes, if the rubber boot has been damaged or has become detached at one end, water may penetrate the guide pin sleeve and cause corrosion. Light corrosion can sometimes be successfully cleaned up with a wire wheel and a wire-type bottle brush (or rifle brush) in a drill. A mildly worn caliper will cause uneven wear of the pads/rotors and may pull the car slightly to the side during initial braking. A moderately worn caliper may also become sticky and under certain conditions may even chatter or hammer. A badly worn caliper may freeze momentarily or permanently, reducing braking and warping the rotors. Removing frozen caliper pins may require extended applications of a top quality penetrating oil. At every pad change you should check each guide pin in its bushing -mine wiggle a little and this is probably normal, but slop is not. This gives you a chance to properly clean and lube the guide recess. Shoot with spray brake cleaner and use a rifle cleaning brush to clean the inside of the bore. When removing a caliper, hang it up with a length of coat hanger wire or a plastic tie to prevent damage to the brake lines. After cleaning the guide pins and sleeves, use a good synthetic
brake grease to extend the life of a worn caliper. Note that for Bendix
calipers, an affordable repair kit is available (guide pins, sleeve
inserts, rubber boots, bolts), so these calipers can often be fully
restored. For Girling (Lucas) brakes only a guide pin repair kit is
available (pins, boots, bolts). Repair kits containing piston seals and
dust covers are also available from Volvo for both types of calipers,
but by that time you should probably be looking at replacement calipers.
Now if the guide pins are damaged by pitting from corrosion or are badly
worn (uncommon as they are rarely worn more than a couple thousandths of
an inch) and the recesses are in good condition then simple guide pin
replacement can extend the life of Girling calipers, but I wouldn't
consider that a proper restoration. In most cases, new guide pins and
replacement caliper frames with good sleeves would be all that's needed
to restore Girling calipers. Replacement caliper frames are available This, with occasional re-lubrication of the guide pins using synthetic
brake grease, will maximize the service life of your semi-restored or
re-built calipers. Note that the high grade hex insert caliper mounting
bolts are torque to yield and technically should be replaced, but few
people ever do. Clean the threads and torque to 105 Nm (77 ft-lbs) using
a drop of red Loc-Tite. The caliper guide pin bolts are tightened to 30
Nm (22 ft-lbs) -make sure the back, flat square is fully seated (hold it
in place with a 19mm open end wrench to prevent rounding the corners). Rattling Sound from Worn Guide Pines or Spring. [Dave Stevens] TSB 51907 dated Feb/94 covers '83-'91 700 series with Girling (Lucas) 2-piston front brake calipers. It simply mentions that excessive wear between the caliper guide pins and their bores might, in some cases" cause a rattling sound and that a guide pin replacement kit is available (P/N 271854-2) containing guide pins, bushings, dust seals and mounting bolts. Obviously this was not a totally uncommon problem for Volvo to have even bothered writing up the TSB. As you and the others notes, a much more likely cause for front brake rattling noise is a broken anti-rattle spring on one of the brake pads. You can inspect these without removing the pads. If you're going to change the pads you should always pop the dust covers, clean and lubricate the caliper guide pins using high temp silicon grease. Use the same grease between the back of the pads, the stainless anti-rattle plates and the piston faces to help minimize any tendency for your brakes to squeal. If you've got ABS, now is also the time to clean up the tips of those sensors (check the 740 FAQ and archives for notes on this). Sticky Caliper: Internal Corrosion. [Inquiry] Despite replacing componens, I still have what seems to be a bit of pad drag (very intermittent, comes and goes). Should I suspect a sticky caliper piston? Rebuild It Yourself or Buy a Rebuilt Caliper? [Tips from Editor/Chuck Jeckell] The shop I worked in insisted on rebuilding calipers in-house. 60% or so had pitted pistons and/or bores. Caliper repair kits don't come with pistons or sleeves, so I'd buy the rebuilt calipers from a reputable rebuilder. Consider the cost and quality of doing it yourself: you do not have the tools or the expertise to extract rusted bleed screws, re-tap threads, polish pistons and bores to correct dimensions or insert sleeves, and make the caliper leak-and-seizure-free. Buy a rebuilt unit with a guarantee. Quality Checks on Rebuilt Calipers. [Tip from Larry] Most rebuilders of Volvo parts are up to speed on the necessary quality of the cores they rebuild. However, Girling placed a cast-dimple at the bottom of each "half" of the front calipers. Mis-matched, incorrectly-rebuilt front calipers will have a dimple at the bottom and a dimple at the top. The resulting internal cross-directed hydraulic pressures will cause bleeding problems and weird failures of an otherwise sound brake system: remember a Volvo without ABS has 2 separate hydraulic systems. Second, take metric wrenches with you to the parts store make sure the bleed screw threads in the caliper are capable of holding the bleed screws, and while you're at it, do a visual inspection of the threads and seals in the caliper. Occasionally a Volvo owner/mechanic will break a brakeline as it enters the caliper. Rebuilders have been known to ruin the caliper threads when they remove the broken flare-nut from the caliper body, so you gotta look there also. The test will come when you install them and bleed the brakes: look for leaks and piston seizures. Often the brake pads used in rebuilt sets are at the low end of the quality scale; you may want to replace them. In any event, make sure the new pads will fit the rebuilt calipers: sometimes the rebuilder refaces the inner surfaces and does not leave room for the pads. Avoid these problems by purchasing only high-quality rebuilds from a reputable retailer who will back the parts if problems arise. Removing Caliper and Installing a Rebuilt Caliper. The only difficulty installing a caliper is likely to come from corroded brake pipe or line fittings. See the notes below for tips. To keep fluid from escaping the master cylinder with a brake line open: 1) Disconnect battery negative (or pull relevant fuse) to keep brake lights off. 2)Connect a bleeder hose to the caliper (hose routed to waste container). 3) Open the bleeder, then slowly press the brake pedal to the floor and block it there till you are finished. 4) Slowly press the caliper piston back to expell as much fluid from caliper as possible. 5) Close bleeder and remove caliper for bench work. Ignore the Above and Rebuild Them Yourself? Check This Advice First. [Tips from Dave Stevens] Here are some caliper re-build tips from my own experience with my '95 940 (Lucas-Girling jumbo type 2 w/ABS). Unless you have access to compressed air, before removing the caliper and disconnecting the line, pop the piston almost all the way out using the brake pedal. Use the backing plates of old disc pads (or something equally thick) as a guide to how far you can safely push the piston out before it is about to go past the seals and spill fluid all over the caliper. To fully remove the piston, I prefer to do it on the bench to minimize the mess, but you can also swing the caliper away from the rotor and wrapping it in a towel use brake pressure to push it out. When removing the caliper you can clamp off the hose using something wide that won't damage the hose and its interior lining -a section of heater hose or a wound rag with locking pliers works fine for most people. Once on the bench you can usually easily blow the piston out with air (a tire pump with one of those tapered plastic fittings will often do the job). If you have trouble getting the piston out it's best to put it back on the car and use pedal pressure. Although not recommended, you can twist and pull the piston out, but you mustn't risk scratching the outside of the piston with anything like pliers. Either grab the rough inside of the piston with expanding pliers or try something like wedging in a single jaw of a large pair of channel lock pliers or use something fairly benign like an F-clamp with those plastic jaw covers or a smooth faced c-clamp wrapping a few turns of protective tape around the protruding piston. The front caliper repair kit from Volvo includes two sets of piston dust covers, seals, guide pin dust covers and guide pin brake grease. Take this opportunity to replace the seals as well as the dust covers. It wouldn't be a horrid idea to do both front calipers to keep them performing evenly -a sticky piston can cause some initial pulling during braking. The caliper seal grooves are slightly tapered to aid in sealing and retraction. It's sometimes hard to tell, but the seals (at least the ones I've encountered) have a slightly tapered cross-section to fit these grooves. Use calipers (the measuring kind) or try to stand the seal on edge on a smooth level surface to determine which, if any, would be the narrow edge of the seal -it installs as the leading edge. Lubricate all mating surfaces with lots of clean brake fluid as you go, especially the inner seal and the back edge of the piston. Pull the new dust cover onto the back of the piston. It will fold inside out as you do this, just fold it back so the lip is sticking out and can be inserted (pushed) into the caliper slot. Now you're ready to push the piston back through the dust cover lip. Although not usually a problem with this caliper design, to avoid damage to the seals press the piston straight in and not at an angle. Advance slowly. Apply force in the center of the piston using something like a large c-clamp. If the piston or clamp walks to the side immediately back off and straighten out. Initially it may seem like you're using a lot of force, but as long as you remain lined up it will suddenly pop into place and move in easily. Once it's pushed in all the way make sure the front lip of the dust cover is properly seated over the piston. When re-installing the caliper, lube and check the caliper guide pins for wear and replace as needed. After the hose is reconnected, remount the caliper loosely and perform an initial bleed (note that DOT4 fluid is called for). Then remove and hold that caliper facing down at an angle and tap the caliper vigourously with a mallet to dislodge any air bubbles that may be clinging to the walls inside the caliper, on the piston and around the seal so they will float to the top. Re-mount the caliper and bleed some more until this process runs clear. Torque the caliper mounting bolts properly to 105 Nm (930 inch-lbs). FYI it's 30 Nm (265 inch-lbs) for the guide pins and an even 90 Nm (63-65 ft-lbs) for the wheel nuts. Read the FAQ sections on bleeding. Replacing the fluid and then pressure bleeding is certainly the best way to go and doesn't need a helper. Rear Brakes: Rear Ate Caliper Pins. [Inquiry] When replacing the rear Ate brake pad securing pins, is Loctite required or would spring tension be sufficient to hold them in place? [Response 1: Tom Irwin] No way dude! Loctite there will ruin your day. As you install the pins, notice the truncated, conical sleeve that is at the head of the pin. I usually give each one a light kiss with a hammer to seat them a bit more firmly. However, the tension springs are designed to retain the pins. [Response 2: Alan Carlo] Spring tension holds the pins in place. I put a light coating of anti-seize compound on the pins to prevent them from rusting in place. I have been doing it this way for many years without a problem. Inspect the pins though and if they are badly rusted or the spring on the end is damaged or missing replace them. I usually seat the pins with a pair of channel lock pliers as the spring makes it hard to use a hammer and punch. Rear Brake Disk Removal. [740] Chilton's repair manual tells me to remove the center grease cap when replacing my rear discs; but it does not appear to have grease caps and is not obvious to me how to remove. [Response:] Had mine off last week. The disks fit pretty snugly over the axle hubs and a bit of rust can glue then in place. Try knocking them loose with a few hammer blows. Also, you may need to loosen the handbrake adjustment (inside the car) to let the disk clear the shoes. Rear Brake Piston Rotation. [Inquiry:] I'm about to attack one of the ATE calipers on my wife's 740 to cure a squealing brake problem. I've been thinking it must have a stuck piston, but in doing a little pre-reading in Haynes (good illustration) and Chiltons (well....), they talk about the pistons being in the proper rotation and its effect on brake squeal. It seems there is a little step in the piston surface that meets the pad, and it is supposed be oriented to 20 degrees. I never noticed they were built that way. Does anyone know if it is very likely that they ever get rotated out of the proper position, and if so, what's the effect? [Response: Jim Holst] The ATE piston is supposed to be oriented in the bore so that the part of the piston in the direction of the forward rotation of the rotor is slightly higher than the other side of the piston to reduce brake squeel. The piston notches are angled 20 degrees from front to rear. According to the manuals, you use Volvo special tools 2919 and 2918 to measure and turn the piston. Not having the special tools, I just replace the pads and assume the piston hasn't moved in the bore. To turn the piston in the bore you need a tool which will fit inside the piston and expand to grip the piston. Sort of a c-clamp in reverse. [Response: John B] There's supposed to be a stainless steel shim between the piston and the pad...the shim has two punch-outs that fit in the rear caliper pistons at the proper angle. Although you can use the special Volvo tool or make one yourself, I've been satisfied with eyeballing the angle using the shim....the piston can be rotated with a needle nose pliers or a screwdriver tip...be careful not to tear the rubber dust cover/seal. Adjustment: [Inquiry:] How do I adjust my parking brake? [Response: John Kaiser] Remove the rear center ashtray from the console and the plastic mounting plate behind it by prying slightly on the two locking tabs on the bottom using a thin knife or screwdriver. Adjust the cable housing with wrench or pliers so that the handbrake lever can be tightened to 7-8 notches of which the first two must be free travel. Braking action should be felt at the fourth to sixth notch. To tighten, rotate clockwise. Also check cable at rear differential left side. Sometimes the cable pivot wears and comes loose. You may have to check the parking brake shoes by pulling rear rotors if you cannot procure satisfactory p-brake adjustment. [Response:: Leo R.] Adjustment: If you remove the ash-tray-holder behind the lever cover you'll see an adjustment for the whole brake. In cars without "multi-link" (the majority of 740's, it is common that one of the 2 brake cables is going to fail due to broken strands or a loose or rusty fastening which couples the right cable to the left. Easily seen when you lift up your car a little. Cable Replacement: Replacing One Side of the Cable. [Inquiry] How do I replace one side of my emergency brake cable? [Response: Peter Fluitman] Remove the right wheel and the caliper (no need to break into the hydraulics). Then pull off the rotor which is secured by the screwed-in guide pin. Remove the handbrake shoes. The cable is held in by a pin in the actuating mechanism. Assemble the cable in the mechanism and feed it through the backplate. Remember to put the rubber boot back. Feed the cable through the 2 loops on the axle casing. Then attach the other end of the cable. You'll need to slacken the cable off inside the car underneath the centre console (you shorten the outer cable). You'll need a couple of new R clips for the clevis pins. I normally remove both, clip the link to the new cable, then stick it back onto the pivot on the axle. Re-fit the handbrake shoes, the disk and the caliper Adjust by setting the cable back to give you 5 or 6 clicks on the ratchet. Replacing the Long Cable Assembly to the Console. [Tips from Ken] A few months ago, the little 'peg' on the end of the cable that goes into the parking brake lever broke, leaving me with no parking brake. Not a big deal since the car is an automatic, but something I still like having the use of. The job started out by opening up the center armrest/console area and removing the rear ashtray and ashtray mounting fixture. Loosen up the cable to the max by turning the plastic adjusting nut as much as possible. Loosened the lugnuts of both wheels (just in case) and jacked up the rear of the vehicle (after chocking the front wheels on both sides from rear and front... THIS IS A MUST) and placed it on jackstands. Herein lies the troubles that I encountered: I do not have a nice floor jack. I have a bottlejack. What happened is that the bottlejack brought the vehicle up to a nice height, BUT when I lowered the car back down on jackstands located under the axle, the car would lower even more since the weight was still on the suspension. This resulted in a very low clearance. Not the ideal situation for getting under the vehicle. You need a good amount of clearance to comfortably get under the vehicle to disconnect things Second problem. The long cable goes to the LEFT parking brake. I removed the left wheel and rotor and removed the brake shoes. Removing the parking brake shoes is a huge pain because of the strong springs. While I was at it, I banged out the wheel studs because they needed replacing. Figured it was a good time to take care of it. I threaded the leftside cable back towards the center of the vehicle where there was a little mounting piece and started disconnecting things. There are 2 cotter pins and R-type retaining clips there. This is where my second problem occurred. One of the pins and clips came off with no problems. I chose to save and reuse the clip. The other clip came out without a problem but the pin was rusted in there pretty solidly. This pin held the rightside cable in. Great, time to break out the PBlaster spray. After wiggling and banging at the pin for a good 10 minutes, it came out. Finally, with everything disconnected, I threaded the cable back. About 1/2 between the rear axle and the hole into the console inside the vehicle, there is another retaining bracket. In order to remove the cable, you have to undo the bracket, at least I think you do. This requires a 10mm wrench for one side, and a 10mm socket for the other side. Finally, a little yanking and tugging and a lot of bad words later, I got the cable out. Putting the new cable in was very, very easy and you basically just do everything in reverse. So, what have we learned? If you have a lift and power tools, this job will take you all of 15 minutes. If you are like me, it will take you 2.5 hours including cleanup time. On the plus side, I have a working parking brake again, and it feels much more smooth and consistent than it used to before! 960 Cable and Shoe Replacement [Tips: Paul Golden] In a 960 with independent rear suspension, the rear e-brake hardware and shoes and dust shields were all gone and the cable from lever to axle was broke, all thanks to extensive rusting. There was no way I was taking out the gas tank to access the cable above. I was able to replace the cables by removing the exhaust system behind the catalytic converter as well as the heat shield. There is a cable clamp close to the heat shield that holds the cable off the heatshield to prevent rattles. I removed the center console and fished the new cable from inside. The two other cables were not fun. The aluminum had oxidized around the steel sleeve and made the cables very hard to remove, but with patience, lots of PB Blaster, and a pair of vise grips on a slide hammer I was able to work them out. I cleaned up everything and made sure the cable routing matched the original installation. The new dust shields were quite difficult to replace: they do not fit over the rear hub. I had to make a small cut in the new shields and remove the studs from the hub to get the job done. Installed new springs, hardware and shoes, put the studs back in hubs, installed rotor and brakes, adjusted hand brake and reinstalled the center console, heat shield and exhaust. Total job was over 7 hours and not fun. But if I had followed the man |
Power Bleeder from Motive Products: 
fine vice the recommended 20 psi. If you use pressures recommended (~20psi), you will not be in any danger of blowing off the fluid reservoir. I routinely use 25psi with a pressure reducer and have never had a problem. Just don't try to hit is with a spare pumped up to 45psi, or hook up to a 150psi air hose! In this case, it will surely come apart somewhere! Only drawbacks: under heavy - i.e., daily use, the gaskets on the reservoir bottle got funky and required replacement, as did the gasket on the master cylinder reservoir adapter cap. After lots of use, the adapter cap failed and began leaking - threads would not hold. The cap itself seemed to either wear or stretch such that the threads would not hold tight and would slip. The result is that there was a very fine line between tightening the cap and having the cap pop up one thread resulting in lots of fluid (like a whole container) being blown out around the cap threads. My solution was to purchase a machined aluminum adapter cap from a local automotive tool supply house for about $30 and use it in place of the supplied adapter cap. For complete system flushes, I find that the supplied reservoir bottle may be too small. This may be appropriate for the owner with 1-4 Volvos that get flushed every 1-2 years and the occasional new master cylinder or caliper. The Volvos cannot be gravity bled, and even with the pressure bleeder, you may need to use the pedal occasionally when bleeding the rear brakes on those cars with rear brake pressure limiting valves (non-ABS systems).
Since your car is new you don't have to worry about rust so everything will come apart easily. If the car is more than 3 years old, it is generally good to replace the hardware (i.e. brake pad retaining pins and retaining clip).