Rustproofing your vehicle

By Don Chapman

I suppose for those who buy new cars and keep them only 1 or 2 years, rust proofing is something of a waste of time, but for those of us who keep our Volvos a fair number of years, anything which slows down the ravages of time and rust can only be a good idea. A few things to bear in mind before starting to rustproof your car are:-

1. The car must be completely dry.
2. Choose a warm day - rustproofing fluids spray and flow much better than when it's cold.
3. Wire brush mud off from the underside.
4. Be careful where you do the job, overspray of rustproofing fluids can make unite a mess
5. If you work inside your garage, make sure you have as much ventilation as possible, to avoid build up of solvent vapours.
6. Be careful to avoid any naked lights or other sources of ignition, solvent vapours are very flammable.
7. When working under the car, use a pit if available, and make sure the car is safely supported on axle stands when removing the wheels to work underneath.
8. Be careful not to spray on to some plastics as some fluids can attack them if left on - so wipe off excess.

What do you need?

Rustproofing fluid, Dinitrol of the correct type, or Waxoyl are two that I have used, and both seem to be well regarded by the Classic Car press. I find Dinitrol excellent to apply by spray, Waxoyl often needs to be thinned with white spirit before spraying. Without doubt to make the best possible job of rustproofing, the fluid should be applied using a compressor and appropriate spray guns. This enables the fluid to be blown into all nooks and crannies. I use a spray gun for the underside and under the wheel arches, and the same gun but with the nozzle replaced by a flexible probe about a metre long for treating the insides of all the closed areas (doors, sills etc). Check Halfords major tool stores - possibly tool hire shops for compressors, etc.

Where to treat

Under the bonnet
The hollow stiffening sections on the underside of the bonnet, and the two large box members running each side of the engine. Both are well endowed with holes through which to insert the probe. The method I use is to insert the probe, press the trigger on the spray gun and slowly withdraw the probe keeping the trigger pressed - this should ensure thorough coverage of the internal surfaces.

Front doors
Treat through the drain holes at the bottom. Whilst the front door is open, remove the courtesy light switch and treat the 'A' pillar through the hole - use the probe both upwards and downwards before replacing the switch. Beside the outer edge of the 'A' pillar is a gap between the pillar and the outer wing. The probe can be inserted through this gap, and surfaces of inner and outer wings treated. At the rear of the front door opening is a plastic plug, at the base of the 'B' pillar. Remove this plug and use the probe to treat the 'B' pillar upwards and downwards.

Back doors
Again, treat the doors via the drain holes. Remove the courtesy light switch from the 'B' pillar and treat the pillar upwards and downwards. At the rear of the rear door opening are 3 plastic plugs. Remove these and treat the closed section as thoroughly as possible through each hole before replacing the plugs.

In the boot
Pull the boot lining material away from each side, and spray fluid into the join between the wheel arch and the outer wing.

Sills
There are a number of drain/ventilation holes in the bottom of each sill. Treat each of these with the probe, forwards and backwards. Obviously treated areas will overlap, but at least this reduces the risk of missing any of the surfaces, and can do no harm.

Underside
Thoroughly treat the inside of all the box sections underneath, including suspension components such as the trailing arms. Using the gun without the probe spray fluid on the entire underside. This is trickier than it sounds, and needs some care to ensure that all surfaces are properly covered.

Wheel arches
With the car solidly supported on axle stands, remove the wheels. Wrap a dustbin bag or something similar securely a-round the hub/brake assemble. Wire brush off excess mud and thoroughly spray under each wheel arch.

After the fluid has had a few days to set, it's a good idea to repeat the process. This helps to ensure complete coverage, and builds up a thick waterproof covering. The underside and wheel arches in particular have a hard time, being bombarded with water, salt and grit, so a thorough job is vital in these areas. Wipe overspray from painted areas before it sets, it's easier. When you finish treating your car, leave it outside with the windows open to get rid of smell, and solvent vapour. I know Volvos are pretty well rustproofed at the factory, but a bit of help can't come amiss. If you spend £100-£150 on rustproofing, how much rust damage can you get repaired for that sort of money?

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