2005 Silverado Drums Keep Self-adjusting Too Tight

PhotoJoe · May 28, 2009

Ok, I know this is nebulous, and there could be a million things going on, but I'm hoping to find a solution that has evaded me and my shop.

I took my truck to a local tire shop for a brake job. This shop is VERY reputable, has always taken good care of me, stood behind their work, etc. I trust them....I think.

They said my rear brakes were shot and needed new shoes. This was at approx 48,000 miles. Fine. They did the shoes and turned the rotors.

Approximately one month and 1200 miles later, the drums were warped. Truck would shake like a banshee when stopping, I could feel it in the peddle but not the steering wheel. Took it back and they replaced the shoes and turned the drums again. They did not figure out which wheel it was, but the brakes felt good again....for about 2,000 miles and 2 months.

Took it back again...."Oh, we must have missed turning a drum". Turn the drums.....I'm getting frustrated. Leave. One month and 1,000 miles, warped again!

Took it back. They said the right rear self-adjuster was messed up. They said the little lever that should engage the teeth was free-floating off the teeth by about a 1/4 inch, thus allowing the brakes to continually tighten. They replaced the adjuster mechanism and turned the drums.

So, that was a month ago, just over 1,000 miles and they're starting to squeak again and I feel the pulsing coming. I've had it! I can't imagine I can turn the drums anymore. They've got to be thin!

Is there anything anyone can tell me that can solve my problem? Can the adjusters be installed backwards and would that cause this? A sticking cylinder (though they check these every time I'm there), a sticking valve somewhere?

I'm at my wits end with this truck. I'm tempted to tie a brick to its axle and throw it in the river.

Thanks in advance for any help you can offer. I appreciate it more than you know.

Mr_Rooney · May 28, 2009

I am old and now forget many things from the past. But I think the self adjusting only occurs when the vehicle is braked in reverse. Then the small arm comes down and if there is enough play between the shoe and drum, the adjustment occurs. I also think those adjusters, the threaded bolts with the toothed wheel, are right and left side dependant. So, if the brake shop mixed them up, you could be adjusting while braking in the forward direction.

And I could be completely wrong on this.

Maybe the E brake cable is partially froze?

PhotoJoe · May 28, 2009

I am old and now forget many things from the past. But I think the self adjusting only occurs when the vehicle is braked in reverse. Then the small arm comes down and if there is enough play between the shoe and drum, the adjustment occurs. I also think those adjusters, the threaded bolts with the toothed wheel, are right and left side dependant. So, if the brake shop mixed them up, you could be adjusting while braking in the forward direction.

And I could be completely wrong on this.

Maybe the E brake cable is partially froze?

Thanks Mr Rooney,

I'll look into the parking brake cable, though both sides have been replaced in this whole process. (I too am getting old and forgetful, or I would have mentioned that!)

I think I'll order the manual and look at the diagram. That should tell me if they're put in the right way. I'll also look at the hole in the backing plate to see if it lines up with the teeth. I paid these people to fix it, I should not have to do this!

DBVille · May 28, 2009

I am old and now forget many things from the past. But I think the self adjusting only occurs when the vehicle is braked in reverse. Then the small arm comes down and if there is enough play between the shoe and drum, the adjustment occurs. I also think those adjusters, the threaded bolts with the toothed wheel, are right and left side dependant. So, if the brake shop mixed them up, you could be adjusting while braking in the forward direction.

And I could be completely wrong on this.

Maybe the E brake cable is partially froze?

You are correct - only in reverse - if they didn't get them swapped. And, your call on the brake cable is good as well - it could be not fully releasing, wearing, and the adjusters do their thing, and repeat.

rogerf · May 29, 2009

Personally never have any success "turning" drums or rotors. Always seem to just warp and end up doing the job over so don't even bother anymore, just replace. Have also seen these mechanisms completely freeze from salt/rust/infrequent use but usually fail toward a slack adjustment. Would lean more toward an internal hardware problem as your root cause such as a broken, or weak, or misplaced brake spring. IIRC the adjustment lever is held onto the star-adjuster by a spring mechanism, would be a good place to start.