why do rear brakes lockup?

Question

left rear brake locks up with very little pedal pressure

Answer 1

Second person more right but normally the drum can get spiral groves in it and the drum can spin in to the some plate and jam the shoes into it. Most likely some of the self adjusting mechanism has came come loose and or fractured and fell in between the drum and the shoe and when you step on the brakes it locks up because it's jamming the shoes so tight into the drum that it freezes up then works it's way out when you let off and back up. There is one other thing that could do it but it's doubtful, that would be a bad wheel bearing but it would have to be really bad, It's easy to check the wheel bearing by just jacking up the car and wiggling it to see if it's loose or not. Aside from the loose wheel bearing I have seen loose rocks inside the drum and don't know how they got there except the adjustment covers where gone and allowed them to get in. Anyway replacing the shoes and turning the drum will get rid of this problem, if you do it yourself it cots $30.00 for shoes $30.00 to turn the drums and $18.00 to replace all the old brake hardware on both wheels. If you have to replace the drums they can run from forty dollars to a hundred and twenty each. Hope this helps.

Answer 2

Brake springs broke makeing the brakes bind .

Answer 3

WHICH CAR TYPE!! Most trouble comes from OLD SPOILED brake fluid use. OR BAD replacement parts or a jambed up PROPORTIONER valve. MOst cars have this to distribute fluid pressure VARIABLY from front to rear. GOOD LUCK!!

Answer 4

If it's a drum brake, it's probably out of adjustmment. If it's a disc, tbe caliper may be in need of rebuild or your proportioning valve could be bad.

Answer 5

if drum brake check for contaminasion on brake shoes

Answer 6

you need brake grease and probably new brake hardware in the rear....something loose broken inside.. or the back plate is broken..... c link good luck .... too easy . rite tools.







http://www.youtube.com/watch?v=MCpCkun2qxA

Answer 7

brake shoes or pads contaminated from leaking wheel cylinder, brake caliper or defective brake hose going to the caliper............gl

Answer 8

Whatever everyone else said