Brake lockup

[Matthew Currie]

I know this is a subject that has come up before, but has anybody come up with a really definitive answer to what causes the rear brake (always the left) to lock up, especially when it's wet?

I replaced the shoes and springs and it got worse instead of better. I can't see anything wrong.

Any bright ideas?

[Eagle]

I've never read anything definitive on this, but in my experience this always happens first thing on a damp morning. I am firmly convinced that it is primarily a function of the brake shoe lining material, but until I install metallic or ceramic shoes and confirm that the problem has been banished, I'm only guessing.

[CheapXJ]

It's because the rear brakes are drum brakes, and drum brakes suck.

Especially the ones on an XJ D44 that seem to be worth their weight in gold at parts houses :mad:

[juicexj24]

When I replaced the wheel cylinders and shoes/drums two weeks ago it has stopped locking up on me. I could have guessed the lock up was from the bad wheel cyl. both were shot, and the shoes were caked it rust. Just an idea but the right job seems to fix the lock up.

[Nick]

I had a YJ in the 80's that did that same thing. I had to replace both wheel cylinders and it stopped immediately. Isn't it nice first thing on a sleepy eyed drive to work when you attempt to stop and you sound like you slammed your brakes on going 100mph

[ACE]

Alright here's my theory. Went through this whole brake grabbing thing recently too on my '90 with 300K miles on it. Put on new shoes but didn't have the drums turned. Result, brakes grabbed and basically wouldn't let go even when I had the adjusters totally out. Crap. Had drums turned so that the outer lip was removed, put them back on. Result, brakes still grab, dangit! Got new drums, grabbing gone. Took a look at old drums wondering why a turned drum wouldn't work since it was as smooth and true as the new one. I noticed the inside lip was barely touched when it was turned so there was that slight ridge still there. For shi$* and giggles I took them in and had them re-turned to get rid of that ridge on the inside of the drum. Got home, put them on, sure as shi%*, no grabbing. Moral of story, I think that after enough wear on the drum to form that inner ridge occurs, somehow and eventually, that ridge grabs the shoes and pulls them out and perhaps moisture allows the pads to expand slightly thereby exacerbating the problem. :dunno:

[Rags]

My thoughts exactly.............Drums...........Belled or out of specs.............also look for grooves in the backing plates where the shoes contact them...you get wear channels in the backing plates over the years from the shoes rubbing on them and this causes some weird stuff like grabbing and popping...........machine your drums and spec them proply.....if in doubt replace them..............also look at simple things,do you have the primary and secondary shoes in the wrong position?It happens to the best of us...............................Rags:D

[Matthew Currie]

Thanks to all. I Guess I'll have the drums turned next and see if that helps. They do have a little ridge on them, and the Jeep has 173K miles, so I wouldn't be surprised if they need attention. If that doesn't do it I'll do the wheel cylinders.

I did wonder if I'd screwed up and put the shoes on wrong but they're right way around and nothing else seems wrong.

If I get a solution, I'll report back.