By Chris Dougherty
Chris Dougherty is a certified RV technician. Here is a letter he received about adjusting trailer brakes from a reader while he was serving as RVtravel.com’s technical editor.
I have a new Coleman camper that seems to have a brake issue. While it stops okay, one tire seems to “lock up” (“grab”) first. This happens while adjusting the brake controller. I feel that I would have better braking and a shorter stopping distance if all four tires braked at about the same time. I know that I don’t need—or want—the brakes locking the wheels in normal use. But while making adjustments to the controller I would like to have them better synchronized. Is there a way to adjust the brakes to get them all braking together?
Absolutely, the brakes can be adjusted. I’m going to assume that the trailer is level for towing, and the tires are all inflated properly. If one wheel is grabbing and the other aren’t, and the trailer isn’t equipped with self-adjusting brakes, then there is a procedure for adjusting the brakes on each wheel position. I would recommend going through this procedure for all the wheels so you know they are adjusted properly.
I’m not sure which axle/brake system you have on your unit, but here’s Dexter Axle’s directions for adjusting the brakes, right out of their Operation, Maintenance and Service Manual. By the way, you should have a book in your owner’s packet about the axles and brakes for your RV. If not, they’re available online from the axle manufacturer … just look for the ID sticker on one of the axles.
Trailer brake adjustment
Brakes should be adjusted: (1) after the first 200 miles of operation when the brake shoes and drums have “seated,” (2) at 3,000-mile intervals, or (3) as use and performance require. The brakes should be adjusted in the following manner:
1. Jack up the trailer and secure on adequate capacity jack stands. Follow trailer manufacturer’s recommendations for lifting and supporting the unit. Make sure the wheel and drum rotates freely.
2. Remove the adjusting hole cover from the adjusting slot on the bottom of the brake backing plate.
3. With a screwdriver or standard adjusting tool, rotate the starwheel of the adjuster assembly to expand the brake shoes. Adjust the brake shoes out until the pressure of the linings against the drum makes the wheel very difficult to turn.
Note: For drop spindle axles, a modified adjusting tool may be necessary.
4. Then rotate the starwheel in the opposite direction until the wheel turns freely with a slight lining drag.
5. Replace the adjusting hole cover and lower the wheel to the ground.
6. Repeat the above procedure on all brakes. For best results, the brakes should all be set at the same clearance.
After this is done, repeat the adjustment and synchronizing procedure for your brake controller. If you’re not comfortable doing this, any RVDA/RVIA Certified Technician can perform this procedure for you. Also, if this doesn’t fix the problem, occasionally there can be a mechanical problem inside the hub, and that should be serviced.