Keeping your brakes working correctly is an essential part of caravan maintenance.
When it comes to a do-it-yourself checkup on stopping power with drum brakes, you have some basic choices. Presuming the drums are in good order, the leading replacement parts are the brake pads and the electric magnet that powers the mechanism. You can replace the individual components or swap the backing plate as a complete unit.
Many caravan repair centres suggest installing a new backing plate, and when I spoke to the folks at Couplemate Trailer Parts in Brisbane, they agreed. I have used Couplemate for many years for trailer parts, and its service and advice have been spot on. I was told that replacing individual parts is time-consuming and requires a higher skill level, so I chose the complete units. There’s an added cost but the bonus is that the whole assembly, including wiring, activation arms and springs, is all new.
My Trakmaster uses 12in drum brakes on a tandem setup, and you will discover a variety of setups, including standard and offroad versions, as well as the choice of Dexter or AL-KO styles. Naturally enough, tandem setups require two left and two right side plates, while single-axle vans need one of each. Standard brakes have on-road magnets that can rattle on the steel actuating arm, causing the arm to cut into the steel magnet housing. On the other hand, offroad magnets have a plastic insert to prevent rattle and wear, so they last longer on corrugated surfaces.
My van’s brakes are Dexter, which are the same as AL-KO except for the handbrake mechanism. You can modify the handbrake wire to suit, but if Trakmaster thought they were better, they must have had a reason, so I decided to stick with Dexter despite them being $55 extra per plate at $175. The total cost was $700 plus $55 freight for four sets.
Getting started
When working on a caravan’s underpinnings, you must accept that they are heavy and need a safe, flat working environment and suitable tools. A task like replacing brakes is also time-consuming, so consider where you work and who else might want to access the spot. It is also relatively dirty — you will come into contact with brake dust and grease, so some suitable thin gloves are handy.
You need to lift the wheel safely, but first, loosen off the wheel nuts so they are easier to remove, then jack the wheel from under the suspension and rest it on a secure block or jack stand. Tap off the bearing cover, remove the split pin and the castellated nut and the brake hub will slide off. The outer bearing will come with it, so don’t let it fall into the dirt. To remove the drum, you may have to back off the handbrake by winding the star wheel adjustment through the inspection hole on the back of the brake backing plate with a special spoon tool or a wide screwdriver. (see the image on step five). Then, tap the drum off to show the brake mechanism.
Now, it’s time to remove the handbrake lever from the old backing plate to allow the plate to slide off. The handbrake operates only on the front setup on my tandem axle van.
Cut the 12V line close to where it’s already joined to the brakes at a place suitable for accommodating the new wire. Then, undo the five nuts holding the plate on. The bolt holes are laid out so that the new backing plate will fit in its correct alignment with the drum, but make sure you have the right-side assembly for the right (driver) side and the left plates for the left.
Install the new bolts on the new plate and reassemble them with the supplied nut and spring washer set. Torque them to 91Nm (67ft lb). Solder the 12V activation wire and ensure it has a suitable travel length that won’t be snared on flying sticks and stones.
We now replace the drum, reinstall the bearings and set them to the correct tolerance and adjust the brakes so the wheel spins freely with a slight scraping sound. Reattach the wheel, lower the van and move on to the next wheel. All up, the changeover should take about two and a half hours for four wheels, including a cup of tea halfway through, and once completed, take the van for a drive to check everything is working correctly. Remember to check the wheel nuts once you have travelled a 100km on your first trip to ensure they are tight.
As always, only undertake work on your van if you are confident and capable. If in doubt, leave it to the professionals.
STEP 1 — Old brake assembly
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 STEP 2 — Remove the old plate |
 STEP 3 — Dexter offroad backing plate |
 STEP 4 — Old and new brakes |
 STEP 5 — Adjusting brakes |
 STEP 6 — New plate in place |
If in doubt, consult a professional
Improper maintenance can lead to injury, death or property damage. Maintenance work of this nature should only be undertaken by people with suitable competence. The information provided is general in nature, not comprehensive and should only be taken as a guide. Individual discretion must be exercised and persons undertaking described tasks do so completely at their own risk. Publishers and creators of this content accept no responsibility for loss or damage.
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