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How to manually adjust your trailer brakes

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.

Dear Chris,
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?
Jeff

Dear Jeff,
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.

##RVDT1799

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Paul T
7 months ago

Yeah… about #3…

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.”

I did this last fall at a campground when I suspected a brake was acting up. Turned out, the star wheel would adjust to tighten the brakes, but wouldn’t turn back to loosen them. The flange side was hanging up on the brake spring at the bottom of the shoes, so that it was impossible to back it down after tightening up. I had to pull the drum from the wheel, remove the brake assembly and limp home on three brakes. The procedure is good, but before you tighten the brakes to the point the wheel is locking up, check and make sure you can go back the other way!

Thomas D
7 months ago

Or better yet,throw the cheap crap away and put on disc brakes
no adjustment necessary
I can’t believe that trailer manufactures continue to use drum brakes
take away the cost of drum and apply that to disc
it wouldn’t be that much difference

Gary Broughton
7 months ago

My father told me 60 some years ago to tighten the wheel until it doesn’t turn then back off the star wheel 7 clicks. I been doing this forever and don’t have wheels locking up.

Bob Palin
7 months ago

1. Jack up the trailer”

Let me stop you right there, my fifth wheel weighs 11,000lbs, how am I going to jack it up?
In any case no jack I have is tall enough to raise the fifth wheel.

I do have the one wheel locking problem which I “solved” by backing off the gain until it didn’t happen, presumably this has made the other wheel’s braking less efficient but it stops OK.

Crowman
7 months ago
Reply to  Bob Palin

You buy a hydraulic jack that will fit under the axle (buy a good one not a China made piece of garbage, you’re going to be under the trailer) Use blocks under the jack if needed as you’ll only need to lift the axle around 4 inches to clear the ground with the tire.

Eric Devolin
7 months ago
Reply to  Crowman

DO NOT jack on the axle as you can deform it and cause alignment issues with the wheel/tires not tracking correctly. Jack under the leaf springs using a piece of wood ( 2×4) to keep the jack head from slipping off the flat of the leaf spring.

Tommy Molnar
7 months ago
Reply to  Bob Palin

You can get a hydraulic jack from Harbor Freight that will easily raise one wheel at a time off the ground. There is no need to raise the whole trailer. I did this all the time with my travel trailer which only weighs about 8k.
I had disc brakes installed three years ago and never looked back. No adjusting necessary.

Mike Hancock
7 months ago
Reply to  Tommy Molnar

Was it a Dexter axle that you added disc brakes to?

Tommy Molnar
7 months ago
Reply to  Mike Hancock

Gee Mike, I’m not sure. It’s whatever Arctic Fox was using back in 2012. When we had them installed down in AZ, the guys installing just asked what kind of trailer we had and brought what they needed. I think discs can be installed on any axles. We listened to a disc brake seminar at the Good Sam/Camping World RV Rally in Phoenix and signed up. They installed them on our trailer at the RV park we were going to be staying in Brenda, AZ, about 90 miles from Phoenix.

That has nothing to do with your question but I just thought I’d add it . . . 🙂

Bill
7 months ago
Reply to  Tommy Molnar

Those worried about hydraulic jack failure(Chinese or otherwise) should always use safety stands along with the jack. Also, many axle and or trailer manufacturers specifically warn against using jacks on the axle or recommend specified points to place them.

Tommy Molnar
7 months ago
Reply to  Bill

I’ve heard that, Bill, but jacking the axle off the ground maybe two inches isn’t going to hurt anything. I’d be more worried about trying to get the frame high enough to actually lift the tire off the ground. Remember the old car jacks they used to put in the trunk of cars to change tires? Man, you had to jack the bumper to the moon to get enough space between the tire and the ground to change it. I have used my little hydraulic jack for changing tires on my trucks and trailers for years, always putting them under the axle and lifting maybe 2″ off the ground.