If you’ve been driving on unsealed roads in Central Australia in recent weeks – as I have – chances are you’ve had to find your way through a certain amount of mud. Use of 4WD plus careful driving techniques can get you through most situations. However, mud, unlike water and sand, is sticky, which means that, just because you’re safely back on the bitumen, you’ve not left all the mud behind. Some of it will have attached itself to your vehicle.
There are two kinds of this residual mud. The first kind is called “cosmetic mud”.
This delicately coloured film will be a delight to some 4WD drivers, who look forward to the considerable street cred it can attract provided it’s still there when you get home. For them, it’s a tragedy if it all gets washed off by a sudden downpour while they’re travelling on the bitumen.
For others, it’s just brown icky stuff which keeps getting onto your clothes while getting into or out of the car, and the quicker they can get to a car wash and have their car restored to its pristine factory colour, the better.
In either case, there’s just one safety rule to remember: once you’re out of the mud, make sure that all lights, number plates, plus windows and mirrors used by the driver are cleared of mud.
The second kind of residual mud is called “functional mud”.
This kind of mud has the potential to impact the efficient performance of the vehicle. For example, wheel arches, especially the rear ones, can become packed with mud, and restrict the movement of the wheels. If this has happened, you’ll need to dig enough of the mud out of the wheel arch to allow the wheel to move freely. If the mud is still wet, most of the rest of it will then gradually drop out while you’re on the bitumen.
If you have the chance to drive through patches of water on the bitumen, this can help to remove some of the mud on the underside of the car.
If mud is allowed to dry, it can become hard and firmly attached to the surface it’s on. This can in turn hinder the performance of any underbody component which needs to be kept cool. A visual inspection while the car is on a hoist is the easiest way to check this.
Probably the most likely problem to be caused by mud is wheels out of balance. (I’m assuming here that your wheels were in balance before you got into the mud.) You can usually get an idea of whether this is an issue as follows: while travelling at a moderate speed on a quiet, smooth, straight road, take your hands off the steering wheel for a moment, and notice whether it is shaking from side to side. If it is, you may have lumps of mud stuck on the inside of one or more wheels. Solution: take the wheels off and remove any mud. The rear wheels are the most likely offenders. If the problem doesn’t go away, you may need to get the wheels rebalanced and/or realigned.