The pre-trip caravan brake check most tourers skip

Twenty-one years I spent under bonnets before I started writing about tracks instead of fixing rigs to get across them, and if there's one job I've watched more tourers half-do than any other, it's the brake check. Everyone checks tyre pressure. Half check the bearings after I harped on about it. Almost nobody actually gets under the van and looks at the brake magnets and shoes before a big lap. They just plug in the plug, drive off, and assume electric brakes are a "set and forget" system. They're not.

I've pulled into more than one roadside recovery where the caravan's brakes had been doing roughly nothing for months. The owner had no idea, because a tow vehicle with decent brakes of its own will mask a dead trailer brake system almost completely on flat, dry bitumen. It's the descent into Kangaroo Valley, or the long pull down off the Cunningham Highway, or a wet stop at a T-intersection with a loaded 2.8 tonne van behind you, where you find out the truth. By then it's not really a great time to learn.

Why electric brakes fail quietly

Most Australian off-road and road-going vans run electromagnetic drum brakes, a magnet on the backing plate that gets energised by your brake controller and pulls against the spinning drum to force the shoes out. Simple system, decades old, generally reliable, but it has a few specific failure points that don't announce themselves.

Dust ingress is the biggest one. Drum brakes are open to the world at the backing plate, and if your seals are tired or the drum's been through a few water crossings, fine bulldust and iron-rich Kimberley mud gets in and glazes the shoes. Glazed shoes still move, they just don't grip properly. From the driver's seat, through a heavy tow vehicle, that can feel like a slightly softer pedal rather than an outright fault.

Magnet wear is the other one. The magnet face wears unevenly over tens of thousands of kilometres, and once it's worn past a certain point it can't fully energise the shoe even with the controller maxed out. I've seen magnets worn to almost nothing on vans that were "serviced regularly" — serviced, in this case, meaning someone repacked the bearings and never actually pulled the drum off to look at the brake gear underneath.

Then there's the wiring. Vibration on corrugations shakes brake plugs loose, corrodes pins in the 7-pin or 12-pin plug, and cracks the insulation on the cable running along the chassis rail. A single dead brake on one wheel doesn't always trip a warning on your controller. It just means one side of your van is doing all the work, and that shows up as the trailer pulling sideways under brakes, usually towards whichever side still works.

The check I actually do before a trip

This isn't a full brake job. It's a fifteen-minute inspection that tells you whether you need one.

Jack each wheel, pull the drum (most off-road vans use a simple two or three bolt access or a full drum-off design, check your specific hub), and look at the shoe lining thickness. If you can't tell by eye whether there's meat left, there isn't enough. Compare side to side; uneven wear front-to-back on the van tells you something about your brake controller's gain setting or a sticking actuator.

Check the magnet face for scoring or a worn ring pattern. A magnet that's glazed shiny smooth, rather than showing a slightly rough even wear surface, isn't gripping the drum properly and needs replacing, they're a cheap part and not worth nursing along.

Look at the drum's inner surface for scoring, heat cracking (a bluish tint from overheating) or an out-of-round wobble when you spin it. A drum that's gone oval will pulse under brakes and won't let the shoes seat evenly no matter how good the shoes are.

While you're in there, follow the brake wire back from the backing plate to the plug. Look for chafing where it runs near the chassis rail or suspension pivot, and check the earth connection, a bad earth on one axle is one of the more common "my brakes feel weak on one side" complaints I get asked about at caravan parks.

Setting up the controller properly, not just plugging it in

A perfect set of brakes wired to a poorly set brake controller is still a poor braking system. Most electric controllers, whether they're the older time-delay type or a modern proportional unit, need the gain set for your actual loaded van weight, not whatever it was set to when you bought the tow vehicle.

Do this on a quiet, straight stretch of road, loaded as you'll be travelling, not empty. Apply the manual override lever on the controller at a moderate road speed and see whether the van brakes firmly without locking the wheels or feeling like it's barely there. Too little gain and the tow vehicle does all the work, which cooks your vehicle's brakes and wears your tyres unevenly over a long trip. Too much and you risk locking the van's wheels on wet or loose surfaces, which is how jack-knifes start.

I'd argue most people set gain once, at delivery, and never touch it again even after adding 200 kg of camping gear, water and gas bottles to the back of the van. That's the wrong way to run it. Recheck gain any time your loaded weight changes meaningfully, and definitely recheck it before a big trip where you'll be running heavier than your last weekender.

If you're unsure what your actual loaded weight is sitting at, that's a separate problem worth sorting before you touch the brake controller at all. Our towing weights explainer covers ATM, GVM and payload in plain numbers, and it's worth knowing where you sit before you load the van for a lap.

Where brake checks intersect with everything else under there

You're already under the wheel with the hub apart, so it makes sense to check the bearings while you're there rather than treating it as a separate job on a separate weekend. We've got a dedicated piece on wheel bearing checks that covers what a failing bearing feels and sounds like before it costs you a hub, and honestly the two jobs go hand in hand. Same drum off, same wheel apart, same fifteen minutes of your time either way.

Independent suspension vans and leaf spring vans wear their brake components slightly differently too, mostly to do with how evenly weight transfers under braking and how much the axle articulates on corrugations. If you're trying to work out what actually matters for your setup, our independent suspension versus leaf springs breakdown is worth a read before you assume your brake wear pattern is normal for the van.

What this looks like on an actual trip

Take the descent off the Toolangi side down into the Yarra Valley, or the run down into Wilpena via the Flinders Ranges loop, and you'll find out fast whether your brakes are doing their share. I did a full check before a run through the Red Centre Way a couple of seasons back and found one magnet on its way out, glazed almost smooth, on a van that had done maybe 40,000 km since new. The owner had no idea. That's a $40 part and twenty minutes of labour that saved a genuinely bad afternoon somewhere on the descent past Kings Canyon, loaded, in 40-degree heat, brakes already working harder than usual.

Corrugations make all of this worse faster. If you're planning anything like the Gibb River Road or the Savannah Way, you're shaking every connection in that brake system loose at a rate that a bitumen tourer never sees. I'd check brakes before and after a serious corrugated run, not just once a year on the calendar.

Servicing intervals worth actually following

The National Heavy Vehicle Regulator and most manufacturer handbooks suggest brake inspection intervals tied to distance rather than time, but I'll be blunt: distance-based servicing assumes bitumen-only travel. If you're doing gravel, corrugations or beach access regularly, halve the interval you'd use for a van that lives in a driveway between Christmas trips. A full pull-apart and inspect every 10,000 to 15,000 km of touring is a reasonable target for a van that actually goes places, tightened up if you've done anything rough.

Get a mobile mechanic or a caravan-specific service centre to do it if you're not comfortable pulling drums yourself, but don't let anyone tell you a "brake service" that doesn't include pulling the drum and looking at the shoes and magnets is a real brake service. It's a wheel bearing repack with a brake sticker slapped on the invoice.

Relevant Australian Standards for trailer brake systems (AS 4177 covers trailer construction including braking requirements) exist for a reason, and while you're not required to re-certify your van's brakes before every trip, working roughly to that standard's intent, functioning, proportionate, reliable brakes on a loaded trailer, isn't optional if you're towing anything over the light-trailer threshold that doesn't need brakes at all.

The bit nobody wants to hear

If you've owned the van more than two years and genuinely can't remember the last time someone pulled a drum off and looked inside, that's your answer. Book it in, or get the jack out yourself this weekend. It's not a big job. It's the job that decides whether the descent into a caravan park with the drum brakes worn thin ends with you parked calmly at the boom gate, or with a bloke like me getting a call about a jack-knifed van at the bottom of a hill.

— Dan "Dusty" Whitlock, 4WD & Tracks Editor