Rear Brake Over-adjusting
 

Vehicle information: Working on an '85 W350 Chassis. (Under my '78 body) All frame parts, axles and brakes are '85 vintage.

Prefix: All new pads, rotors, drums, shoes, rear brake cylinders, lines (both hard lines and soft) and master cylinder within the last year. Shoes are on correctly, not backwords. Double verified-twice (quad-verified?)

Where I stand now: Every two to three months, my rear, drivers side shoes will overadjust and cause drag and/or lockup in my drum. Emergency brake hasnt been used in over a year. Cables are shot, and wont release brakes.

Question: Why on earth does this keep happening? It drives me (and my very helpful wife) nuts, and is likely to warp my drum and ruin my shoes.

Plead: PLEASE HELP ME... PLEASE, PLEASE, PLEASE!

Thanks guys, Scooter.

did you make sure the lever thing is holding the adjuster properly?

If you are referring to the spring loaded jobby, it appears to be. it applies pressure to the cog and only lets it rotate one way.

sounds like the right part. i don't know why it would tighten up. did you make sure it is greased?

Like a pig at a county fair.

i am out of idea's. something is not right. i have never had an issue with mine yet.

Yeah, me to. I cant figure what the issue is. Maybe too tight or loose of adjuster spring? Not enough or too much tension?

i would almost think there is not enough pressure on the lever thing since if seems to be letting the adjuster turn so easily.

Hmm... Maybe I should see about snugging that up a bit and run it for a while. Cant do any worse than it already is.

I don't claim to be a brake specialist of any sort but I had something similar happen on my 91 where the rear brake drum was over adjusting. I noticed it because I smelled burnt brake shoes. Discovered a bent spring J hook where it went into the shoe and the cable for the adjuster came off the guide. The guide actually looked a little bent. Now which came first, the chicken or the egg, I don't know but the lever that catches the adjuster gear didn't reach anymore and looked like it wore down the edge that catches the teeth. At a glance, I didn't really notice it. but when I took it apart, there it was. Bought a new hardware kit for it and hasn't happened again. But I've got my fingers crossed.

I will most likely have it all apart in the morning, so I will look more closely at that. Thanks for the tips. It seems like an adjuster rebuild kit shouldnt run more than $20 or so. Maybe I should just replace it and call it a day.

Well, as I predicted, my drum warped. I could use the bed of my truck for a paint shaker when I hit the brakes.

Got a new drum today. They took my warped one in as a warranty, so my new one was no-charge. Also bought a new adjuster kit. Cost about $6.00. I'll throw that in and see what happens.

Pulled my drum off to find this:
Attachment 43427

My best guess is that between the heat of the sticking shoe and the warped drum beating the tar out of it, the shoe gave up the ghost.

Ugly. Good luck with that.

I did put all new everything on there. New drum, new adjuster kit, and new shoes (did both sides, since I was in there.) I also dissassembled the threaded adjuster (piece that legthens to adjust tension) wire brushed it, brake cleaned it, then lathered it on the threads in oil. It looks like it spent some time on the Exxon Valdez. I took a pic of the assembled system. Ill try to post it, to see if you guys think I did something wrong. It is set up the same way it was before I did all the new parts.

Wow, that thing must have gotten really hot to warp. I better take mine back off and have it checked. What kind of shoes did you go with?

These: http://www.oreillyauto.com/site/c/de...0068&ppt=C0009

Look alright to you guys?
Attachment 43307

Looks fine to me.

looks good from here.

I was curious about the rear shoes because some of the rebuilt ones I've seen have considerably shorter pads on them. They are the ones that are glued on instead of riveted. I noticed that yours are new and riveted also just like the factory ones.

Thats why I went with these ones. They had another set, but they were the glue on type, which I assumed was a reman. These have a lifetime warrenty (against defects), whereas, the others only had a two year.

I dont get it.... Its doing it again. Seems to be free while backing but when going forward, it is almost totally locked up. Im running out of ideas. New shoes, new drum, new adjuster kit.... What else could be causing this?

Edit: Just had a thought... Could a tire that is out of balance cause this? The vibration cause the adjuster cog to "shake" forward? I would think the springs would provide enough tension to prevent that, but I dont want to rule anything out.

Anyone? This thing is driving me nuts.

might have to ask the guys over on RCC. with all new parts it should not be doing this. i don't think a vibration should cause the issue. i thought they where only suppose to self adjust when you stomp on the brake while driving in reverse but i am not too familiar with the axle you have.
http://ramchargercentral.com/vehicle-help/

Thats the way I understood it to work as well. Im not a member over there, and I hate to be that guy that joins just to ask one question. Can you post without joining?

You got to join to post but there is a lot of good guys there that probably won't mind helping you.

So... I got tired of the over-adjustment, so as a temporary fix, I grossly under adjusted them. I know, I know... That isn't the right way. Truck still stops fine, but since the fronts are doing all the work, the pedal requires a bit more pressure than I care for, and I'm sure I'm eating pads much faster. I give up. I'm going to swap it to disc brakes in the rear, and never worry about drums again. Found a kit for about $300 (I think- I don't have the link in front of me.) Uses CNC cut brackets and Chevy brake calipers. Ill make a new thread when I find my pry-bar to get my wallet open.