Rear brakes locking up

[Ceeker]

Start from scratch. change fluid and bleed calipers. check the caliper boots-peel them back to check for corrosion on the piston. I suspect your rears are gradually seizing up while driving. they are probably hanging up when cold but as you drive, the rotors heat up due to friction causing them to grab more and finally lock them up. as they cool off they loosen off. just my theory.. :-)

[S62]

Start from scratch. change fluid and bleed calipers. check the caliper boots-peel them back to check for corrosion on the piston. I suspect your rears are gradually seizing up while driving. they are probably hanging up when cold but as you drive, the rotors heat up due to friction causing them to grab more and finally lock them up. as they cool off they loosen off. just my theory.. :-)

I did that before but it help with anything, I also replaced the brake lines. I was already planning on getting new calipers so those are coming in tomorrow along with new pads ( I ordered these things before I posted this thread)

[Vtec?lol]

Just let the car get completely cool, like next day cool.

to do the test I post earlier you have to have the car on. Just follow those steps.

The reason I said it could be bearings is it's happened on my 325e. It had the 2.93 LSD and even if one bearing is seized, with the LSD it will lock both wheels up. I too thought it was the brakes but it wasn't but it could be. That's why you should try the method I post.

Let the wheels spin for a while and listen for rubbing or grinding. Then use your finger or a laser thermometer to see if the rear rotors are cool. If they're hot, it's the brakes. If it's cold, it's one or more of the bearings in the rear end.

[S62]

Just let the car get completely cool, like next day cool.

to do the test I post earlier you have to have the car on. Just follow those steps.

The reason I said it could be bearings is it's happened on my 325e. It had the 2.93 LSD and even if one bearing is seized, with the LSD it will lock both wheels up. I too thought it was the brakes but it wasn't but it could be. That's why you should try the method I post.

Let the wheels spin for a while and listen for rubbing or grinding. Then use your finger or a laser thermometer to see if the rear rotors are cool. If they're hot, it's the brakes. If it's cold, it's one or more of the bearings in the rear end.

Ah that makes perfect with LSD. And I do this with the car on when its on jack stands? I just wanna make sure im doing everything right. The brakes only lock up like 1 to 2 times a week and I drive a lot so I doubt the rotors will heat up when I do this test. You know what I mean?

[AndrewBird]

If the clevis on the booster rod that attaches to the brake pedal is screwed too far out, it will just slightly engage the brakes and the booster will slowly force the brakes on. It may have come loose and moved. Something simple to check. You should have just a tiny bit of play in the brake pedal. If there isn't any, this could be your problem.

Another way to check it is to pull the vacuum line off the booster when it does it and see if it fixes it. Releasing the pressure in the booster should free it up.

[S62]

Fixed the brakes, ended up being the rear calipers

[S62]

Nope nvm

[fronton]

Did you ever figure this out? sounds like it was working fine a for a few weeks then bad to problems? I have the similar issue.