4WD Trackside Repairs

Michael Borg — 27 July 2015

When it comes to those lengthier Outback trips, mechanical breakages and general servicing is just part of the game. Even if your vehicle has been running like an absolute freight train, you never know when you’ll come across another traveller who hasn’t shared your good fortune.

A little extra bush mechanic knowledge can really help someone out of strife.

With that in mind, here are a few common problems to keep an eye out for while you’re out on the road, along with the bush fixes I’ve used on my northern adventure so far


If you’ve been travelling on dry and dusty tracks, check your air filters condition regularly and make sure you carry a spare.

Finding a leak

Probably one of the most common problems to come across is a tyre with a slow leak which, believe it or not, is one of those things that can cause bigger problems down the track if you don’t catch it early. If you let it get worse, it gets flatter and ends up shredding the tyre, which destroys it altogether.

There’s a few ways to find a small leak, the most popular being the soapy water method. Simply spray soapy water over the fully inflated tyre and watch for air bubbles. If you don’t have soapy water, or you just can’t spot the leak, the next best method is to find a clear river or stream and completely submerge the wheel and tyre, then watch carefully for any air bubbles and track it down from there. Pay particular attention to the tyre bead and the valve, too.


I’ve actually got little habit that helps me keep a close eye on my wheel bearings. All I do is make sure I check the wheel bearings every fuel stop as soon as I jump out of the car. I look for any visual signs like grease spray on the rim. Then I’ll put the back of my hand against the top of the tyre to feel how hot it is. A warm tyre could also indicate an underinflated tyre. Then I’ll edge my hand closer until it touches the bearing cap. Warm bearings aren’t an issue, but if they’re too hot to touch or hold you know you’ve got a problem.

If you’ve been braking heavily, the whole assembly could also heat up the bearings, so it’s a good time to stop for a break if they’re getting too hot. I also do a basic check for free-play by grabbing the top of the tyre and pulling it back sharply towards me — you’ll know when it’s loose.  


Corrugations play havoc on nuts and bolts. So, every few days, it’s a wise idea to get under your 4WD and run a spanner over any nuts and bolts. Over time, you’ll get to know which bolts commonly come loose, too. I’ve found on both my Cruisers the axle studs, king pin bearings and tail shaft bolts all tend to loosen up.

Plus, the front diff bolts and shock mount bolts need a tighten every 10,000 kays or so. To get a bit of extra leverage, a little trick is to use the ring end of a larger spanner to grip the open end of the original spanner and tighten things up.


If there’s one thing I’ve learnt over the last few years, it’s to check the tow coupling nut hasn’t come loose while you were driving, particularly on the poly-block coupling. The bolt thread on older couplings can stretch over time, and cheaper imported products often use poor quality steel that stretches prematurely, too.

As a result, after a few days of travel I like to nip up the nut and make sure it’s nice and tight. It’s also a good idea to apply a thread locker additive on the thread to add some extra strength and grip.

If the coupling gets damaged altogether, one last resort option is to remove it completely and keep the poly block attached using the pin, peg and a good sized washer.


One of the most common problems for late model utes up north is overloaded rear springs and damaging the chassis. It’s actually quite common for the rear leaf springs to completely invert. In most cases you can continue driving the vehicle to the closest town, but there are a few little tricks that can help take the load off the springs.

First up, drop your tyre pressures nice and low to help smooth out those harsh bumps that your springs will find it hard to deal with. Secondly, shift the weight around to take the load off the back springs. You can do this by moving stuff in the tray as far forward as possible, and moving the gear in the trailer further back, or even ditching the extra weight.

In extreme cases, where the spring mount completely fails, you can wrap a heavy rated ratchet strap around the diff and the leaf spring mount to stop it moving forward or backwards, and wedge a block of wood between the diff and chassis to support the body’s weight. Obviously this is an extreme case to get you to the main track only!

Check out the full feature in issue #91 August 2015 of Camper Trailer Australia magazine. 


4WD repairs 4WD vehicle repairs bush mechanic