Top tips for working on dirty off-road 4x4s

If you've seen the latest episodes of the Universe's Greatest 4x4 Channel, then you'll have seen we brought back our Cheapest Hilux (CLICK: fixing it, CLICK: dyno tuning a diesel, CLICK: bushdoof adventure) and we are into both modding and fixing. Because this was the cheapest Hilux for sale on the internet in Australia, and it's travelled around the planet (and past the moons of Jupiter) several times, this thing has heaps of dirty or rusty bolts, so we have some tips on making your life easier if you've got a car with lots of dirty, rusty bits that you need to work on.

The first step is to try and pressure-wash the undercarriage, ideally with a soapy degreaser and water mix as the water will clean the dirt and organic schmutz while the degreaser chemicals will take care of the oil and grease. 

For really thick deposits of gunk (oil/grease or mud) you'll need to get a stiff-bristle brush in there and scrub-a-dub-dub. If you're working in a well-ventilated area with eye and hand protection, then Oven Cleaner is great for cutting through really oily and greasy sections but you need to be SUPER CAREFUL when using it as it is a catastrophically toxic product.

Once you've got the underside less dirty get in there with a good penetrating spray, like what our mates at WD40 sell. Regularly going around service areas with a couple of squirts of WD will make bolts easier to undo when the time comes, reducing the risk of rounding the head off or snapping them completely.

When you're working under a dirty car it pays to cover your head. Every time you crack a bolt you're likely to wind up with dirt in your hair, ears, up your nose and in your eyes so a pair of motocross goggles, some ear protection and a sacrificial hat should prevent the worst fallout from getting places it shouldn't.

When you unbolt parts check the condition of the bolts and nuts you remove. Replace haggard fasteners so they're easy to refit and then remove next time. It can also be a good idea to run a tap through bolt holes where the bolt threads look rusty, or clean up dirty or rusty studs with a die.

Off-road vehicles are most susceptible to having problems with undoing fasteners thanks to all the water crossings, dirt and mud spray, bashing on rocks, and general age. For this reason alone we'd suggest you buy a large tap and die kit, so you're properly ready in case any bolts or nuts cross-thread, strip, snap or generally play silly buggers when you're thrashing on your nugget.

Keeping an old pallet, even one cut-down to half-size, is an excellent idea. You can ratchet-strap large, heavy parts of the car to it where, if they were on a workbench, they may be free to roll around making the job more difficult. If your assistant falls asleep after eating too many poki bowls you can also ratchet strap them to the pallet for hilarity.  

Finally, a half-inch torque-wrench is absolutely needed when tackling jobs on 4x4 suspension, brakes or the drivetrain. Many of these off-road beasts use torque-heavy diesel engines so the bolts holding it all together are generally large and need to be done up tight. Buy a good quality torque wrench, don't drop it, and get it calibrated every 3-5 years, as this is one tool that is super-handy to have in your kit.