Chattering trailer brakes

[LVJJJ]

Been towing for years, but first time I've run into this.

When applying TV brakes, the TT brakes chatter when coming to a stop. Essentially they are quickly applying, letting loose, applying, etc. Feels like a bad ABS problem on a car.

It's done it with 3 different TV's and with a replacement Prodigy P-2, so its the trailer.

It's an '04 Tahoe Lite 22CB. Brakes are like new, lots of shoe, smooth magnets and drums, wiring looks good going into the backing plates. So, somehow the electrical current going to the brakes is getting interrupted, but it doesn't do it everytime, just most of the time. It gets worse the harder the brake pedal is pressed and also does it when using manual control.

Anybody else had this problem?

(Note - we've had this TT for a year and it's our ideal floor plan so we really like it but there are some strange things about it. This year, 2004, Tahoe of Calfornia trailers have a very bad reputation and this one did have problems, but they have been fixed. It must have leaked a lot under and onto the floor as the entire floor has been replaced. The front window leaked and some framing has been replaced. There have been no leaks from the roof, side or rear walls. I removed the underneath fabric cause it was holding water and replaced it with foam insulation and lots of caulking. The axles, brakes, and bearings look brand new, so the axles must have been replaced also. I rerouted some of the wiring underneath so might have knocked something loose).

[LVJJJ]

For those of you who have been eagerly anticipating the solution to this problem, here it is!

After pre-diagnosing the problem as absolutely electrical, it turned out that it was simply out-of-round brake drums. Apparently overheated them at some point. Got them turned, repacked the bearings and life has returned to normal.

[LVJJJ]

Sheesh. Climbed under the TT to check wiring and found that I had failed to connect the ground pigtail to anything, so haven't had a good ground for anything for a year. All other wiring looks great, all brake wires look good, are good grommets where wires go thru axle and no wire looks chafed. As I mentioned earlier, the backing plate, drums, springs, magnets, shoes are great and look fairly new. No grease anywhere inside.

Haven't towed it yet with ground fixed. While not glad to hear others have had the same problem, at least I'm not alone.

[rbpru]

I am having the same problem. I cleaned, adjusted, and repaired the broken wires. After about 500 miles they chatter as the TT comes to a stop. I have tried adjusting the controller for less aggressive braking and tweeking the shoe adjustment with mixed results.

I have another trip shortly, so I cannot tear them apart till I get back. I will check for grease and chamfer the edges of the shoes. It is strange that it started all of a sudden.

Good luck. I will be watching the replays.

[JIMNLIN]

I bought a used 30' GN tri axle flatbed trailer some years ago. The dealer said his mechanics RR'd the trailer. On the way home with it and one of the brakes chatterd pretty bad.
I do my own RR with any new or used trailers so when I did my brake/bearings inspection I found one of the grease seals had let go and covered the brake drum and shoe in grease. The lining was soaked causing that brake to chatter.
Cleaned things up and replaced the brake shoe and no more brake chatter.

[LVJJJ]

SoundGuy wrote:
Yes, I've had this issue with our own Coachmen and it was none of the above suggestions. Chattering brakes is a mechanical issue and the solution is to chamfer the leading edge of each brake pad, problem solved completely. :B

This makes a lot of sense cause you can see that the shoes are making intermittent contact with the drum so the surface of the drum isn't uniformly smooth.

[SoundGuy]

Yes, I've had this issue with our own Coachmen and it was none of the above suggestions. Chattering brakes is a mechanical issue and the solution is to chamfer the leading edge of each brake pad, problem solved completely. :B

[myredracer]

One possibility is that grease has gotten onto the brakes due to bad seals. We had that happen on a previous TT from the day we got it new and lasted a year until the dealer finally agreed to rebuild all 4 wheels. The symptom you describe sounds like what we experienced but there are other possibilities. I'd jack one wheel at a time and pull the break away pin and see if the brake is working. I'd pull each brake drum off to see what it looks like inside. Drums are easy to pull off.

As mentioned, wiring could be a possibility. Check the wiring in the A-frame area - the main positive wire from battery to mini circuit breaker(s) and to the splices inside the metal box. Check the battery ground connection to the frame. All connections and splices in this area are subject to corrosion as well as problems due to poor workmanship at the factory. I just rewired this wiring and found that the main positive wire from the batter was barely hanging on at the breaker and fell right out when I touched it. No power = no brakes = potentially dangerous.

[LVJJJ]

good point Wayne. When I was fixing things underneath I did pay a lot of attention to the grounds which are very important. Didn't think about the wires going thru the axles tho, I'll take a look. On my last TT I ran 12 gage individual wires from the TV-TT hook-up point back to each brake, maybe should do it on this one.

[WayneAt63044]

Typically the wires to the brakes go through grommets into the axles to run from one side to the other. I've seen these wire's insulation chafe and short to the axle tube. While your wires to the baking plates look good, have you inspected the wires IN the axle? It could be the insulation is worn through beyond where you can visually inspect inside the axle tube. Is the trailer chassis ground good and not intermittent? Good luck.