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Old 01-27-2009, 12:52 PM   #1
Gumby'sC20
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Rear brakes locking up...

My right rear wheel locks up, even under light braking. Truck is equipped with stock drums.

What rebuild/repair process should I follow to help ease the issue (i.e. taking brake assembly apart and lubing components, tighten/loosen cables etc)?


Also, does consistent, daily use of the parking brake effect the calibration of the rear drum components that are causing the locking issue?
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Old 01-27-2009, 01:12 PM   #2
68gmsee
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Re: Rear brakes locking up...

Power brakes? Any changes to the system like addition of power booster, master cylinder?

Does it do it everytime you stop or only when you have to make a sudden stop and really stomp on it.
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Old 01-27-2009, 01:18 PM   #3
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Re: Rear brakes locking up...

I would pull the drum off to see if the axle seal or wheel cylinder is leaking. Once the shoes get wet they lock up. Also if nothing found there consider replacing the rear brake hose. Very common for them to collapse internally.
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Old 01-27-2009, 01:21 PM   #4
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Re: Rear brakes locking up...

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Old 01-27-2009, 01:21 PM   #5
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Re: Rear brakes locking up...

Forgot to add.

Consistant use of the parking brake should not cause maladjustments. Actually it's a good thing to keep it from rusting and not working.
Auto adjusting occurs when you are moving backwards and then quickly step on the brake. The rear stopping motion moves the brake "pawl" or lever downward to tighten the brakes if they are out of adjustment.
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Old 07-09-2009, 10:26 AM   #6
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Re: Rear brakes locking up...

Quote:
Originally Posted by 68gmsee View Post
Forgot to add.

Consistant use of the parking brake should not cause maladjustments. Actually it's a good thing to keep it from rusting and not working.
Auto adjusting occurs when you are moving backwards and then quickly step on the brake. The rear stopping motion moves the brake "pawl" or lever downward to tighten the brakes if they are out of adjustment.

The backwards trick only works if you have Auto adjusters !
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Old 07-09-2009, 11:01 AM   #7
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Re: Rear brakes locking up...

I'd say that the first order of business would be to pull the rear drums and take a look inside to see what you have going or not going.

Probably the biggest contributor is something on the lining as mentioned by ScottH. Leaking wheel seals, leaking wheel cylinders or just a lot of brake dust at times.

If just one is grabbing the one on the opposite side may not be working right and letting that one do all the work also.
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Old 07-09-2009, 11:26 AM   #8
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Re: Rear brakes locking up...

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Originally Posted by mr48chev View Post
I'd say that the first order of business would be to pull the rear drums and take a look inside to see what you have going or not going.

Probably the biggest contributor is something on the lining as mentioned by ScottH. Leaking wheel seals, leaking wheel cylinders or just a lot of brake dust at times.

If just one is grabbing the one on the opposite side may not be working right and letting that one do all the work also.


Probably bad wheel cylinder...............had the same problem, changed cylinder and fixed it a few years ago now I have the same problem.........crappy parts !
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Old 07-09-2009, 04:25 PM   #9
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Re: Rear brakes locking up...

Also, if the shoes are old, they can get hardened and cause a lock up issue. When I first bought my truck, I changed the shoes and it helped tremedously.
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Old 07-09-2009, 08:35 PM   #10
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Re: Rear brakes locking up...

Quote:
Originally Posted by TCLARK View Post
The backwards trick only works if you have Auto adjusters !
All 67 - 72 trucks C&K, 10 - 30 series came stock with self adjusting brakes.


I agree on the possibility of fluid causing this, pull the drum and lok into it... and if all looks good, adjust the brakes out on the side that is locking up. Sounds bass ackwards, but that's how it works.
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Old 07-09-2009, 10:19 PM   #11
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Re: Rear brakes locking up...

Beware of the canadian made brake drums.(CARQUEST) I had 1 of the two new ones out of round that dragged.
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Old 07-10-2009, 05:31 AM   #12
Longhorn Man
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Re: Rear brakes locking up...

the replacement drums are garbage. You are better odd looking in the junkyard for old ones that can be turned
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Old 07-10-2009, 07:47 AM   #13
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Re: Rear brakes locking up...

I just fixed this problem on my S10 don't know it is a possibilty on these trucks. My right rear brake had a broken bolt(only has 2 1/4 bolts) that holds the backing plate to the axle tube. causing it to shift and put that wheel in a bind which in turn would cause my wheel to lock up. Drilled it out, replaced abolt and rebuilt the brakes back there, everythings good now.
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Last edited by BarryB; 07-10-2009 at 07:48 AM.
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Old 07-10-2009, 08:32 AM   #14
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Re: Rear brakes locking up...

Quote:
Originally Posted by Longhorn Man View Post
All 67 - 72 trucks C&K, 10 - 30 series came stock with self adjusting brakes.


I agree on the possibility of fluid causing this, pull the drum and lok into it... and if all looks good, adjust the brakes out on the side that is locking up. Sounds bass ackwards, but that's how it works.



I've got a '72 C10 SWB and it dosen't have self adjusters........Somebody could have changed them, why I don't know !

Last edited by TCLARK; 07-10-2009 at 02:08 PM.
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Old 07-10-2009, 01:57 PM   #15
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Re: Rear brakes locking up...

i had a 69 GMC C/1500 short fleet a few years ago... the dope smoking old man removed the adjusting arms out of all 4 wheels on mine. He told me he was too drunk to remember how they went back together.
There was a lot of worrk on that truck done in this state of mind.
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