rear brakes lock up

[shambone]

my rear brakes lock up when the brake is applied.i don't think the front brakes are working very well. could it be front calipers frozen or propotioning valve, or just needs new shoes? this is an 88 i just bought this week.

[J10/J20 Project]

Look under both sides of the rear wheels and see if you see anything leaking out, on the backing plate or the inside of the rear tire's. looking for a rear axle seal leaking. If nothing is visable then pull the drum's and see if the wheel cylinders are leaking on the shoes. If not then check the condition of the drum and shoes and make sure there within specs.and no major glazing. Your front's do 80% of the braking so I would also check the front pads. and rotors.

Paul

[joe]

You could be over working your rear brakes if the fronts aren't working causing the rears to lock up momentarily. Are they locking to the point of just "sorta locking up" or to the screeching point of locking up? If the later then do what Paul mentioned and check for juice leaks. If the cyl's are leaking though you'd prolly be pumping the brakes to get them to work but I've had two trucks where the axle seal leaked differential fluid on to the shoes and that'll have you come to a "screeching" halt. A Willys PU did this and the rear brakes locked enough to kill the motor. Had to restart and back up to free the shoes then drive home slow w/o touching the brakes.

[Bobbo]

I would first check for brake or axle leaks. Either or will contaminate shoes and make them lock up. Start there, I bet you find the problem. Fix the leaks, replace the shoes, turn the drums and be on your way! Start simple before you go crazy with the hard stuff. The best thing to do is check all your brakes. They are usually neglected on older vehicles. And they are so easy to fix! You will be much safer!

[JAllenWAG]

I recently had the same problem. Wheel cylinder had locked up and was forcing the shoes against the drum all the time. The shoes came off their backing plates and were just spinning around inside the drum.

[Buggzz]

I agree with Joe, The problem may very well be up front as well. Without front brakes, the rears will lock before you feel much "Stopping power" being applied, making it feel like the backs are locking early when in fact the fronts may be gripping late.

Check all the shoes/pads and lines on all 4 wheels, bleed the whole system, and if that fails, take it somewhere.

[shambone]

Hey , thanks for giving me a starting point. i'll check the rears on friday, and post the results. Thanks again,
Scott shampton

[shambone]

This is why i love this site. Not only did you guys give me a starting point, but the advice was right on the money. The wheel cyl.were both leaking (for sometime i might add),and the shoes were down to the steel. I bought new cyl.shoes and drums.(BFH was too big).I'll bleed them tomorrow, and see what else is bad.
Thaks again,
Scott Shampton