'05 Silverado Rear Brakes Locking

**pajeff02** · 09-08-2010, 02:18 PM

Working on a Silverado that the rear drum brakes are locking up on application. Doesn't matter if the roads are wet or dry. Pulled the drums and nothing appears to be out of order. All the springs are in place, I don't see any evidence of excessive heat, no leaking brake cylinders or wheel seals, the lines are not collapsed, good thickness on the shoes still, the mechanicals are all fairly clean...

I am going to check to make sure the e-brake is fully retracted, but since the drums came off without a fight I assume that is not the problem.

I am stumped.

**konigandy6** · 09-08-2010, 02:39 PM

Searching GM service info:

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

In rare cases some owners may comment on a concern with the rear brakes wearing out prematurely, dragging, getting hot or being aggressive. This may be due to the rear brake shoes being adjusted too tight
Recommendation/Instructions:

To correct this concern replace the star adjuster with a new 15 teeth adjuster (original is 30 teeth) part number 19133371. The same part number is used on both sides, requiring two per vehicle.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

**konigandy6** · 09-08-2010, 02:45 PM

That's the only service bulletin I found on locking brakes...

**pajeff02** · 09-08-2010, 03:01 PM

Thanks Andy! It definitely has the higher tooth count star wheel adjuster on it now. I'll back them off a couple of clicks for tonight and see about the kit you mentioned. I assume that is a GM only part?

**konigandy6** · 09-08-2010, 03:50 PM

Originally Posted by pajeff02

Thanks Andy! It definitely has the higher tooth count star wheel adjuster on it now. I'll back them off a couple of clicks for tonight and see about the kit you mentioned. I assume that is a GM only part?

I do believe it is. I kept searching and searching and didn't find anything else. I hope that will solve your problem, but like the bulletin says, it's a "rare occasion"

The only other thing I can even think of would be a pinched brake line since that makes the most sense.

**pajeff02** · 09-08-2010, 05:12 PM

Originally Posted by konigandy6

I do believe it is. I kept searching and searching and didn't find anything else. I hope that will solve your problem, but like the bulletin says, it's a "rare occasion"

The only other thing I can even think of would be a pinched brake line since that makes the most sense.

As soon as I saw that everything looked good under the drums, I immediately traced the brake lines along the axle to see if they had been damaged. Everything looks great. I didn't trace them on the underbody yet though.

This reminds me... I once found a brake hose that had collapsed on a 3rd gen I was working on. This resulted in a locked caliper -- just can't believe a hose went bad on an '05 though. We'll see what it does as I backed each side off a bit.

**konigandy6** · 09-08-2010, 06:36 PM

Originally Posted by pajeff02

As soon as I saw that everything looked good under the drums, I immediately traced the brake lines along the axle to see if they had been damaged. Everything looks great. I didn't trace them on the underbody yet though.

This reminds me... I once found a brake hose that had collapsed on a 3rd gen I was working on. This resulted in a locked caliper -- just can't believe a hose went bad on an '05 though. We'll see what it does as I backed each side off a bit.

If it went bad it was operator error... like wrapping a tow strap around rear axle pinching the brake line... or something along that nature. I doubt an 05 line just went bad.

**JaycenK** · 09-13-2010, 02:09 PM

The full size drums cant be very tight at all. I had this problem on my 98 hoe. You wont see heat problems untill you drive it for like 100miles straight no stopping. On the 95 through 99's it absolutly sucks because the abs modual acumulator has to much volume inside of it and if you have a stiff pedal chances are your drums are to tight. I made mine tight as it was the only way to get a good pedal feel and I ended up smoking the driver side. If they are way to tight the drum will keep adjusting it's self untill it is locked up. Don't know why they do that but mine did twice. as soon as I talked with a master tech and readjusted them it's been fine ever since. Pedal sucks some what but not to bad. Didn't have a bad auto adjuster either. just what they will do for what ever reason.

**bdub2145** · 10-13-2010, 07:23 AM

it sounds like they are adjusted too tight to me

**0rion** · 10-13-2010, 07:59 AM

were the drums hazed? You could also try cleaning that haze off. Last car I worked on was having something similar to what you're having happen. I took some steel wool and cleaned the drums and pads up and all was good. I didn't see anything wrong and the owner didn't want to replace the stuff if they didn't have too so I just cleaned them up and they're still working fine.

**pajeff02** · 10-13-2010, 08:13 AM

It is my stepson's truck. He hasn't complained about the brakes since, so I assume they have been ok. If it pops up again, I'll be sure to check the drum surface better and try this.