Mechanical updates for your caravan

By: Philip Lord, Photography by: Philip Lord

The best mechanical changes you can do to keep your van reliable on tour.

Mechanical Updates For Your Caravan

While it’s true that a caravan doesn’t have mechanical components per se – there is no engine or transmission – there are many moving parts that can fail if you don’t keep them updated. Luckily, in a caravan you don’t find many of them.

A caravan’s running gear is very basic, yet the number of things that can and do go wrong might surprise you. Usually it is a lack of maintenance because the trap that is easy to fall for is to focus too much on the tug’s maintenance and worn parts replacement and to ignore the caravan. A caravan’s running gear will wear out too.

Even though wear depends on how you use your caravan – for ex-ample, if you tow it only on good paved roads or you like to explore outback dirt roads – its moving parts do wear and are prone to failure. Even if you’re not using your van you might find components deteriorate. Replacing them with fresh components is cheap insurance.

Don’t attempt the work yourself if you are not confident on the spanners. Caravan maintenance is not rocket science, but if you have concerns leave the work to a good caravan mechanic.

If it has been a few years since they were fitted, fresh, good quality, greased wheel bearings are a good starting point – this is the one failure part that often is the first to let caravan owners down. Bearings should at least be re-greased and adjusted before any big tour, and it is always a good idea to carry a new spare and split pin.

Get some good quality bearings like Timkin rather than a cheap Chinese brand and make sure that the axle spindles are not damaged with score marks when you’re replacing the bearings. You should have greased all through the bearing, and not just the outer surface, and the correct tension needs to be applied to the axle nut – if in doubt get the job done professionally.


It might sound completely unrelated, but a piece of information that you need to be sure of is your caravan chassis axle load rating. These ratings, usually marked on the chassis, must not be exceeded or no matter how new the bearings are, you will have problems with them failing sooner rather than later. An early warning sign of bearing failure is that they get noisy, but they can let go altogether and the whole wheel and hub assembly can detach from the axle. As you can imagine, if that happens on the road, it is not a pretty sight.

While at the wheels you can inspect the suspension springs, bushes, spring hangers and dampers (if fitted) for damage and make sure that the suspension is properly greased if required.

One of the more common problems out on the road after bearing problems is the brakes. You should adjust the brakes so the vehicle and van are sharing the load, and the adjustment might be different for around town versus out on the open road.

The problem is if you rely too much on the van brakes they can overheat and cause the brake shoes to score and crack or glaze. If the brakes heat up the hub sufficiently, the wheel bearing can boil out and then you have a second problem – a dry bearing, which will eventually seize or fall apart.

Mechanical Updates For Your Caravan 1

A good pre-trip inspection will also check the remaining brake pad or brake shoe material thickness and that the brake drums have not scored and that there is no oil or grease on the linings. Replace the pads or shoes if there is any doubt they might not last the distance of your tour and get drums replaced or machined if they are scored. The same applies to brake magnets – while usually reasonably long lasting, they are relatively cheap to replace if there’s any doubt about their serviceability. One test is to check the magnets’ wires with a voltmeter – they should show 12V with the tow vehicle engine running and the electric brake controller slide applied on full. If there is little or no c\voltage there is a problem with the controller or magnets (or wiring) that needs to be chased down and fixed.

When tightening the wheel nuts, make sure the threads are not worn or damaged and while this is a point of contention, I suggest that you do not oil or grease the threads but only make sure they are clear of grime and grit. Always check the tension of the wheel nuts when on tour – it’s always a good idea to do a shakedown run on a local stretch of highway before the big trip so that you can check all your good work (or your mechanic’s) won’t be undone.


Another potential problem source is the caravan’s park brake, which you want adjusted up enough to hold the caravan when parked up (although always chock the wheels as well, no cable park brake operating on drums is terribly effective) but not too tightly adjusted. About 20mm of slack in the park brake cable is about right, depending on the run of cable.

Greasing the coupling is a good idea to stop noise and reduce friction and heat build-up but you can have problems with securing the coupling if too much grease is applied – or you’ll think it’s secure but the excess grease will mean the locking pin hasn’t engaged and the coupling will detach from the ball when on the move. Use the grease sparingly, or better still use some dry-lube instead on the ball each time you’re hitching up for a long transport stage. Don’t forget to also lubricate the friction points of the load-levelling hitch, if you use one.

While it is not a mechanical component, the caravan’s wiring can be a weak point as it ages and can affect the operation of not only interior equipment and exterior lights but also the brakes. Consider re-wiring at least the brake and external light systems of your van, and up the diameter of the wire yourself to help reduce voltage drop. If it has been left out in the weather for extended periods, replace the trailer plug and also consider replacing light assemblies. Although trailer lights are much improved, they used to be pretty unsophisticated items that would allow moisture in the unit and corrode connections and deteriorate quite quickly. Most plastic trailer wiring plugs are not waterproof either and connections will fail as they corrode within the plug casing.