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Discussion Starter #1
a few times in the last month, my right rear brake has grabbed/seized while driving (when my foot has not been on the brake pedal).

it typically happens in slow city driving in cold weather. the right rear wheel just seizes up for a few seconds. i can hear and feel the wheel dragging along the road, and then there's a 'clunk' that sounds and feels like i hit a pothole and then everything's back to normal. one time, i stopped the car and backed up a few feet, and the wheel freed up.

i know i'll have to do a brake service on the wheel involved, but i was wondering if anyone already has any thoughts about what might be wrong.

i did a google search this morning for 'rear brake grabs while driving' and found this

http://www.explorerforum.com/forums/showthread.php?t=174107

thanks!

edit...the car is a 1989 plymouth reliant with drum rear brakes, no ABS. i use the emergency/parking brake regularly and it seems fine.
 

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When was the last time the shoes and drums were replaced? I had this issue with a 72 Dart, and found that the original drums were worn paper-thin and warped, at 144K miles. it would lock up so badly the right rear tire would leave a patch of rubber, and I wasn't even touching the brake. I suspect that you will need to replace everything.

Until you can work on it, try setting and releasing the parking brake when it does this. That helped reduce the lockup for me, temporarily. If you let it go too long, it will destroy your wheel bearings.
 

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Discussion Starter #3
the car has 68000 kilometers/42000 miles. it was a one owner car i bought last year (estate sale).

i dont think the rear brakes have ever been touched. i have a receipt from 2008 which include new front brakes (pads and rotors) and all new brake lines, but doesnt mention the rear brakes.
 

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Given that age, I'd just replace the drums, shoes, all springs and hold-down hardware, and also clean and repack the rear wheel bearings, using new grease seals.
 

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Also given the age, the rear wheel cylinders may be leaking or seeping. If brake fluid or grease has found its way to the brake shoe lining surface, the brakes will become "grabby" and will lock up at times. There have been many times that I have had to replace leaky rear wheel brake cylinders for this problem.
 

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There may be a spring that has come loose, too, so it is time to take the drum off and look at it to make the determination of what may be happening in there.
 

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Discussion Starter #7
thanks for the responses. turns out one of the springs (the lower brake shoe return spring, #8) had broken in two



cheers! :)
 

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Sounds like a wheel cylinder to me. The piston is stuck. That's why backing up works, the shoe pushes the piston in when you apply the brake. Had this happen on a full size van once and it was the front piston stuck. Having said all that, a broken return spring could almost do the same thing, but given the age I'd almost certainly say replace the cylinders.
 

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It is an easy check to see if they are frozen. Push on one side of the shoe at the cylinder and see if it moves in, move to the other side and do the same. If they move smooth, great, if catchy, rebuild or replace. Don't worry, can't push them all the way out, there is a plate to prevent that from happening, it isn't numbered in the diagram because it is a fixed piece to the backing plate.
 

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This is completely off-topic, but where did you get that exploded view that looks like it's part of an IPL? I've never been able to find those.
 

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