Underbody rinsing off/cleaning

In a way this is one of the simplest things but it’s so important. Even if you keep your paintwork muddy, you really need to wash the underbody off after any 4wd trip. This is especially true of the beach to avoid rust underneath the car that’s harder to see but more critical; but, in a lot of the parts of Australia, you have relatively salty groundwater in amongst the mud so you also need to clean that mud off quickly, too.

If you’re ever going to work on your 4wd underneath, a clean underbody is hugely important as well. Getting dirt in your eyes really sucks and makes it that much harder to fix or modify what you need to.


Nothing too special with the equipment. This is what I use. People often think you need to go super fancy but I reckon the best combo is to keep things simple and cheap.

What’s here is:

  1. A telescopic hose wand with an adjustable head: ~$12 from a hardware store;
  2. A lawn sprinkler in an oscillating style: $20; and,
  3. An air spray nozzle with a small hose/sprinkler adapter fitting attached: $8 and $6.

Contrast this to just brands that sell a magnetic chassis flushing attachment for $100 and you can see how much further you’re ahead.

You can go pressure washers and stuff but then you need to be more careful with where you spray it. This also reduces the barrier to entry and it’s really cheap to do. The air spray nozzle is a great trick: in Australia the air fittings usually use the same thread styles that garden hoses do; finding a small sprinkler adapter meaning you can use the air spray nozzle as a water spray nozzle is a real game changer.

To help newbies to the 4wding game understand how to use this stuff I thought I’d illustrate. My car here isn’t super messy but it has been through a bunch of muddy puddles and wet gravel roads. This is also the style of rinsing I’d do if I’d been to the beach – you absolutely want to rinse off as soon as you get home from a beach run.

Rinsing off with a sprinkler

This is the real underbody soaking that helps shift salt and mud out. First off, if you can be bothered this is a good time to strip the car of bash plates and stuff as they do tend to trap mud and stuff in, but no biggie if you can’t be bothered.

The way I do a big underbody soak is by turning a sprinkler on and driving over it slowly, letting it oscillate underneath the car to really soak it.

After a bit of time with the sprinkler in one spot, I move forwards a bit so it can get the next part of the car.

You continue to do this till you get all the way to the back of the car…

… then I go to the front of the car and use the hose and pull the sprinkler back through.

If you do this correctly, it’ll take you about a beer or other beverage of choice to do which is a perfect way to wrap up a 4wd trip.

Cleaning wand

Again, relatively simple. Usually I go for a shower setting but nothing to stop you using some of the different options to soak and rinse off everything underneath. The important bit here is to focus on the bits outside of the chassis rails and inside things like the wheel arches and stuff – all the bits the sprinkler is going to struggle or be unable to reach.

This is why you want a tilting head along with being telescope. The tilt head makes it so much easier to get in underneath the wheel arches and things.

Another really important bit is to make sure the back of the wheels and the brakes etc are done. These are classic mud and salt traps. It’s not an area where you want super high pressure and so it’s ideal for a low pressure, high volume wand.

Work hard to get into the things like the chassis rail and sill edges, but also all the larger gaps like in the back bumper and stuff like that.

Nooks and crannies

My adapting to an air nozzle is currently a bit more complicated due to using Hoselink stuff (kinda recommended, but it does mean adapting everything to suit it). It’s a lot simpler due to the size to use just a click hose for it, but it does work albeit look kinda funny with an air nozzle hanging off the end of a garden hose.

If you just use a usual click hose fitting it’s a bit neater. The hose fitting is a bit tricky to find, but you can get a 6mm to click hose fitting adapter in the “Pope Universal Sprinkler Adapter” fitting in the Bunnings hose fitting aisle. Technically it’s a 1/4″ BSP fitting that you need but the adapter from the sprinkler adapter works.

Really not much to illustrate with this. You want the longest nozzle you can to help get into tight spots, but this is where you flush out underneath the sill covers/wheel arch extensions but also into all the holes in the chassis and the like.

At this point I’d call it done unless you want to do a full scrub. You’d really do this with a large sized soft wheel brush in a lot of areas, but I think it’s unnecessary beyond getting any salt and mud off.