# Rear brakes locking up in reverse...93 GMC



## greg273 (Aug 5, 2003)

I havent changed a set of drum brakes since high school auto shop... (20 years ago). What would cause them to bind up? I can pump the brakes and get them to unstick a little bit, but they seem to want to grab and not let go, but only when the truck is in reverse.
Any ideas?


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## Beeman (Dec 29, 2002)

Just happen or is this after a brake job?


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## Travis in Louisiana (May 14, 2002)

If I remember right, when you back up the drum brakes have a lever that causes them to tighten up to the drum. Maybe when you put them on they were pretty tight already and when you back up they are getting too tight. There is a way from the back side of the wheel to adjust the tightness of the breakes against the drum. It is usually a wheel that has teeth on it where you can use a screw driver to loosen them some. You could also take the brake drum off and adjust them. I am doing this from memory, because it has been a while since I have changed drum brakes. Later Travis.


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## johncronejr (Nov 4, 2007)

Sounds like you need to adjust the brakes...

I am not certain, but would guess that a 93 model would have auto adjust brake drums...To do this, put truck in reverse and start backing up then apply brakes firmly....repeat once more...

If this does not help then take a look behind the wheel and see if there is a port to reach the adjusting wheel (there should be),...jack that wheel up and then take a large flat blade and start turning the notched brake adjsuting wheel until the brakes are grabbing....then rotate adjusting wheel the other way until the tire rolls freely....

Hope this helps...


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## greg273 (Aug 5, 2003)

Ok, got the wheels off and discovered, on both sides, the brake shoes were broken. Apparently leaking wheel cylinders and seals were causing heat buildup, which caused brake dragging and premature failure. 
Replaced shoes,springs, cylinders,axle seals and differential oil, all told $250 from my cousins auto shop. Glad I took it to the pros, this job was beyond my scope of automotive knowledge...


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