Caravan and Trailer Towing in Victoria: A Mobile Mechanic's Pre-Season Service Check

Towing changes everything about how your vehicle works. That 3.2 turbo-diesel that feels effortless around Melbourne is a different animal with two and a half tonnes hanging off the back on the climb up the Hume, or dragging a pop-top through the Grampians in 38-degree heat. A standard logbook service is set up for a car that carries groceries — not one that spends summer hauling a van to Lakes Entrance and back.

The trouble is that the parts that fail under towing loads are usually the ones a routine service never looks at closely. So before you hook up for the season, here's what actually deserves attention on both the tow vehicle and the trailer — and why it matters more for caravanners than the generic "check your oil before a road trip" advice you'll read everywhere else.

Why towing needs its own service check

When you add a loaded van, you roughly double the mass your driveline, brakes and cooling systems have to manage. Heat is the enemy here. Automatic transmissions, engine coolant, brake fluid and tyres all run hotter under load, and heat is what wears them out or fails them outright. A pre-season towing check is really a heat-and-load audit — finding the components that are fine for everyday driving but marginal once you're at your rated towing capacity in a Victorian summer.

If you only do one thing before the caravan season, have someone assess the vehicle as a tow vehicle, not as a daily driver that happens to have a towbar.

Transmission cooling: the number one towing killer

More tow vehicles are quietly ruined by cooked transmission fluid than by anything else. Automatic transmission fluid (ATF) that overheats breaks down, loses its ability to lubricate and hold pressure, and starts to varnish the internals. By the time you notice harsh shifts or slipping, expensive damage is often already done.

What we look at

• Fluid condition and level. Burnt-smelling or dark ATF is a warning sign. Many modern "sealed for life" transmissions still benefit from a fluid change before heavy towing — "life" is calculated on light-duty use.
• Transmission cooler adequacy. Utes and wagons commonly tow at or near capacity with only the factory cooler. An auxiliary transmission cooler is one of the cheapest insurance policies you can buy for a serious towing rig.
• Cooler lines and the radiator's built-in cooler. On many vehicles the trans cooler shares the radiator. A tired radiator hurts both engine and transmission temperatures at once.
• A temperature gauge or scan-tool read. Knowing your actual trans temp while towing is far more useful than guessing. We can log it and tell you whether you're running hot on grades.

If your vehicle spends holidays towing in the heat, managing transmission temperature is the single highest-value thing on this list.

Brakes: you're stopping a lot more weight

Your factory brakes were sized for the vehicle, not the vehicle plus a van. On long descents — think the Black Spur, Mount Hotham, or the run down into Apollo Bay — brakes work hard and fluid gets hot. Old brake fluid absorbs moisture over time, which lowers its boiling point and can cause a soft or fading pedal exactly when you need it most.

What a towing brake check covers

• Pad and rotor thickness — with enough margin left for a full season of loaded stops, not just enough to pass a glance.
• Brake fluid moisture test and, usually, a flush. Fresh fluid dramatically improves fade resistance on long grades.
• Electric brake controller operation. In Victoria, trailers over 2,000 kg GTM must have brakes that work on all wheels, and vans over 2,000 kg need a breakaway system. We check the controller is gaining correctly and the van's brakes are actually engaging in proportion.
• Trailer brake magnets and shoes on the van itself — worn magnets mean the tow vehicle does all the work.

Tyres: the right pressures for a loaded rig

Tyre failures on caravans and tow vehicles are common precisely because pressures and load ratings get ignored. Under load, an underinflated tyre flexes, builds heat and eventually lets go — and a blowout while towing is genuinely dangerous.

• Load-appropriate pressures. Your tow vehicle's rear tyres usually need higher pressure when towing than the everyday placard figure. Check the vehicle handbook's towing section, or the tyre's maximum load and pressure data.
• Age and condition of the van's tyres. Caravans often do low kilometres but sit for months. Tyres can time out and perish long before the tread wears — check the date code, not just the tread depth.
• Don't forget the spares — on both the car and the van, correctly inflated and accessible.
• Even wear patterns that hint at alignment or suspension issues under load.

Trailer wheel bearing service: the one people skip

This is the classic grey-nomad breakdown. Caravan and trailer wheel bearings run hot, especially on long highway hauls, and they don't get the constant use that keeps a car's bearings healthy. Grease dries out, water gets in during washdowns or river crossings, and a neglected bearing can seize a wheel hundreds of kilometres from the nearest town.

What a proper trailer wheel bearing service involves

• Removing each hub, inspecting the bearings and races for pitting, bluing (a heat sign) or roughness.
• Cleaning out the old grease and repacking with fresh, high-temperature bearing grease — or replacing the bearings if there's any doubt.
• Setting the correct preload so bearings aren't too tight (heat) or too loose (play).
• Checking seals and, if fitted, the condition of "bearing buddy" or oil-bath systems.

As a rough guide, inspect trailer bearings roughly once a year or every 10,000 km, and always before a big trip. It's a small job that prevents one of the most miserable roadside failures there is.

Coupling, safety chains and the hitch

The connection between car and van is worth five minutes of careful attention, because everything else depends on it.

• Coupling. Check it latches fully onto the tow ball, moves freely, and isn't worn oversize. Grease the ball. Confirm the ball rating matches the van's weight.
• Safety chains. In Victoria, chains must be rated for the trailer, crossed under the coupling, and connected so the coupling can't hit the ground if it detaches. Check for cracked welds and worn links, and that the shackles are rated — not hardware-store bolts.
• Towbar and tongue. Look for cracks, rust and loose mounting bolts where the bar meets the chassis.
• Wiring and lights. Test brake lights, indicators, tail lights and reversing lights with the van connected. Corroded plugs are a common cause of intermittent trailer lights.
• Breakaway system where fitted — confirm the battery holds charge and the pin activates the brakes.

The rest of the load-and-heat list

• Engine cooling: coolant condition and strength, radiator condition, and that the fans and thermostat are working — you'll lean on all of it climbing grades in summer.
• Engine oil: towing is severe-duty use, so shorter oil change intervals than the handbook's "normal" schedule make sense.
• Suspension: tired rear springs or shocks sag under tow-ball weight and hurt stability. Weight-distribution hitches and airbags only help if the underlying suspension is sound.
• Battery and charging if you're running a dual-battery or DC-DC setup for the van.
• Tow-ball weight: aim for the recommended proportion of the van's weight on the ball and load the van so it isn't tail-heavy — the biggest factor in van sway.

Get it checked where the van lives

The advantage of a mobile service for this kind of work is obvious: caravans are awkward to drive to a workshop and often live behind the house or in storage. We come to you, check the tow vehicle and the van together as a matched pair, and can road-test the rig loaded the way you'll actually travel — which is the only way to catch a transmission that runs hot or a brake controller that isn't pulling its weight.

If you're planning to be on the road this summer, book your towing pre-trip check a few weeks out. That leaves time to fit an auxiliary cooler, replace bearings or sort out brakes without cutting into your holiday. A morning of preparation now is a lot cheaper — and a lot less stressful — than a breakdown on the side of a Victorian highway on Boxing Day.