How To Prepare Your Vehicle For The Big Lap

A breakdown on the Pacific Highway is an inconvenience. A breakdown on the Nullarbor, 300km from the nearest town in 42-degree heat, is a genuine emergency. The difference between the two scenarios playing out well or badly almost always comes down to preparation. A properly serviced and inspected vehicle, with the right spares and emergency gear on board, handles both situations. A vehicle that left the driveway with dodgy bearings and bald tyres because “she’ll be right” handles neither.

This guide covers everything that needs checking, servicing, or replacing on both your tow vehicle and your caravan before you leave. It’s long and detailed because skipping any of it creates a risk that compounds over 20,000 to 40,000km of towing across varied terrain. Work through it systematically, ideally 3 to 6 months before departure, so there’s time to fix what needs fixing.

Every dollar spent on preparation saves ten dollars on the road. And potentially a lot more than money.

Why Vehicle Prep Matters More Than You Think

Towing a caravan is harder on a vehicle than almost anything else you can do with it. The engine works harder, the transmission runs hotter, the brakes wear faster, the suspension is under constant load, and the tyres bear more weight for longer distances than they were designed for in normal driving. Components that would last another 50,000km in city driving might fail at 15,000km of continuous towing. Bearings, belts, hoses, and brake pads that are “fine for now” have a habit of becoming “not fine” in the worst possible location.

The Big Lap typically covers 20,000 to 40,000km. Much of that distance is remote, where tow trucks charge by the kilometre and mechanics are booked out for weeks. A comprehensive pre-departure service and inspection, done by a mechanic who understands towing, is the single most important thing you can do before you leave. It’s also the thing most people underdo.

The Tow Vehicle: Full Pre-Departure Checklist

Engine & Drivetrain

Full service. Oil and filter change, air filter, fuel filter (critical for diesel vehicles in remote areas where fuel quality varies), spark plugs (if petrol). Use quality oil rated for towing; your mechanic should know the spec. If you’re close to a major service interval (timing belt, transmission fluid, transfer case fluid), do it now rather than on the road.

Cooling system. Flush and refill coolant if it’s been more than 2 years or 40,000km. Check all hoses for cracks, bulges, or soft spots. Check the radiator for leaks and damaged fins. Towing generates significantly more heat than normal driving, and cooling system failures are one of the most common towing breakdowns. If your vehicle has a transmission cooler, check that too.

Transmission. Service the automatic transmission (fluid and filter change) if it hasn’t been done in the last 40,000km. Automatic transmissions work hard when towing and run hot. A transmission failure on the road is a $3,000 to $8,000 repair, plus the tow truck. This service costs $300 to $600. The maths is obvious.

Belts and hoses. Replace any belt that shows cracking, glazing, or wear. Replace any hose that’s soft, swollen, or older than 5 years. A $30 belt that snaps on the Stuart Highway costs $500+ in towing and emergency repair. Carry a spare serpentine belt in your toolkit.

Brakes

Brake pads and rotors. Inspect all four corners. If pads are below 50% remaining, replace them before departure. Towing wears brakes 2 to 3 times faster than normal driving, and mountain descents (Victorian Alps, Toowoomba Range, Tasmanian passes) demand brakes that work perfectly. Don’t start the trip at 50% and hope for the best.

Brake fluid. Flush and replace if it’s been more than 2 years. Brake fluid absorbs moisture over time, which lowers its boiling point. When towing heavy loads downhill, brake fluid can overheat and boil, causing brake fade. Fresh fluid prevents this.

Suspension & Steering

Shock absorbers. If they’re original and the vehicle has over 80,000km, consider replacing them. Worn shocks affect towing stability, braking distance, and ride comfort over corrugations. Heavy-duty or adjustable shocks (such as Old Man Emu, Bilstein, or Tough Dog) are a worthwhile upgrade for towing.

Suspension bushes and ball joints. Have these inspected for wear. Worn bushes cause vague steering and poor towing stability. Replacement is relatively cheap; failure at highway speed while towing is not.

Wheel alignment. Get a full alignment after any suspension work and before departure. Misalignment causes uneven tyre wear and poor handling, both of which are amplified when towing.

Tyres

Condition and age. Check tread depth (minimum 3mm for long-distance towing; replace at 4mm to give yourself margin), sidewall condition (no cracks, bulges, or cuts), and age (replace any tyre older than 5 years regardless of tread depth; rubber degrades). Tyres are the only thing between your vehicle and the road. This is not where you save money.

Spare tyre. Check it’s inflated, in good condition, and the correct size. Many vehicles carry a space-saver spare that’s inadequate for towing. If yours does, consider upgrading to a full-size spare.

Tyres and brakes are your two most critical safety systems. Start the trip with both in excellent condition.

Electrical & Accessories

Battery. Test the battery’s cranking capacity and charge state. A battery over 3 years old should be replaced before the trip. Remote area breakdowns caused by flat batteries are embarrassingly common and entirely preventable.

Alternator. Have it tested under load. The alternator charges your vehicle battery and, through the Anderson plug or DC-DC charger, your caravan’s house batteries while driving. A failing alternator means dead batteries in the van and eventually a dead start battery in the vehicle.

Lights. All vehicle lights working, plus the trailer plug connection checked. Carry spare globes for everything.

The Caravan: Full Pre-Departure Checklist

Running Gear

Wheel bearings. Have them inspected and repacked (or replaced if worn). Bearing failure is one of the most common caravan breakdowns on the Big Lap. The classic symptom is a hot hub after driving; by the time you notice it, the bearing is already damaged. A bearing repack costs $100 to $200 per axle. A roadside bearing failure costs $500 to $2,000 plus the tow.

Brakes. Inspect electric brake pads and magnets. Check brake wiring connections and the breakaway cable/battery. Test brakes at low speed before every trip. If your van has been sitting unused, brakes can seize or corrode.

Tyres. Same standards as the tow vehicle: minimum 3mm tread, no sidewall damage, no older than 5 years. Match the load rating to your van’s loaded weight. Carry a full-size spare for the van as well as the vehicle.

Suspension. Check leaf springs for cracks or sagging, shock absorbers for leaks, and all mounting hardware for tightness. If your van has independent suspension, check the bushes and pivot points.

Structure & Seals

Roof and seals. Inspect every seal on the van: around windows, doors, hatches, vents, and the roof edge. Cracked or peeling sealant lets water in, and water damage is the most expensive caravan repair there is. Reseal anything that looks suspect. Our waterproofing guide covers this in detail.

Chassis. Check the chassis for cracks, particularly around mounting points and where the A-frame meets the main chassis. Look for rust and treat any you find. On older vans, get a qualified technician to inspect the chassis thoroughly.

Systems

Gas. Current gas compliance certificate (required for travel and insurance). Check all gas connections, regulator, and hoses. Test every gas appliance: stove, oven, hot water, heater. A gas leak in a sealed caravan is a fire and explosion risk.

Water. Fill the tanks and check for leaks at every connection, pump, and tap. Run the hot water system and check the pressure relief valve. Clean and sanitise the tanks if they’ve been sitting empty. Test the water pump under pressure.

Electrical. Test the 240V system (all power points, circuit breakers, RCD). Test the 12V system (all lights, water pump, rangehood fan, USB ports). Check house battery charge state and capacity. If your batteries are older than 3 years (AGM) or 5 years (lithium), have them capacity-tested.

Safety equipment. Fire extinguisher in date and accessible. Smoke alarm working with fresh battery. Gas detector working. First aid kit stocked and in date. Emergency exits unobstructed.

Towing Setup

The connection between your vehicle and your van is safety-critical. Check every component.

Hitch and coupling. Inspect for wear, cracks, and correct operation. The coupling should lock firmly onto the ball with no play. If there’s any doubt, replace it. A coupling failure at highway speed is catastrophic.

Safety chains. Correct rating for your van’s loaded weight. No damaged links, no excessive rust. Crossed under the coupling to catch the drawbar if it separates.

Breakaway cable and battery. Test the breakaway system: pull the pin and confirm the van’s brakes engage. Check the breakaway battery is charged. This system is your last line of defence if the van separates from the vehicle.

Brake controller. Calibrated to your van’s loaded weight. Test at low speed: the van should brake smoothly without locking up or pulling to one side. Adjust the gain setting after loading the van, not when it’s empty.

Electrical connection. All lights working through the trailer plug: indicators, brake lights, tail lights, reverse lights. Check the Anderson plug or 7-pin connector is clean and making good contact. Carry a spare plug and basic wiring repair kit.

Weights. Know your van’s loaded weight and confirm it’s within the vehicle’s towing capacity, GCM, and tow ball weight limit. If you haven’t weighed the van loaded, do it. Public weighbridges are available in most regional towns for $10 to $30. Guessing is not acceptable for a 30,000km trip.

Every connection between vehicle and van is safety-critical. Check them before departure and before every drive.

What To Carry For Roadside Emergencies

Even with perfect preparation, things can go wrong on the road. Carry the gear to handle the common problems yourself.

Tools: Socket set (metric), spanners, screwdrivers, pliers, adjustable wrench, multimeter, tyre pressure gauge, tyre repair kit (plug type), 12V compressor, jack (rated for the van’s loaded weight, not just the vehicle), wheel brace that fits both vehicle and van wheel nuts, and a torque wrench.

Spares: Spare serpentine belt, spare trailer plug, spare fuses (for both vehicle and van), spare globes, radiator hose repair tape, cable ties (assorted sizes), duct tape, electrical tape, hose clamps (assorted sizes), and a length of wire.

Recovery: Rated recovery points on the vehicle (not the tow bar), a rated snatch strap (not a tow rope), rated shackles, a shovel, and traction boards (MaxTrax or similar) if you’re going on any unsealed roads.

Emergency: First aid kit, fire extinguisher (an additional one for the vehicle), 20+ litres of drinking water, high-visibility vest, warning triangle, and a torch with spare batteries. If travelling remote, add a satellite communicator.

Our spares and tools buyers guide has specific product recommendations for everything on this list.

The 6-Month Service Schedule On The Road

Preparation doesn’t end when you leave. Ongoing maintenance on the road is just as important.

Every 10,000km or 6 months (whichever comes first): Full vehicle service (oil, filters, inspection). Caravan bearing inspection. Brake check on both vehicle and van. Tyre rotation and condition check.

Monthly: Tyre pressures on all tyres including spares. Wheel nut torque check. Water system check for leaks. Gas system check for leaks (soapy water on connections). Battery charge state and terminals clean.

Before every drive: Walk-around check: tyres visual, lights working, hitch secure, safety chains connected, breakaway cable attached, load hasn’t shifted, nothing hanging loose underneath.

Keep a simple logbook: date, odometer reading, what was done. This helps track service intervals, provides evidence for warranty claims, and adds resale value when you eventually sell the vehicle or van.