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-   -   Brakes stay engaged and grind after releasing brake pedal - any ideas? (http://forum.e46fanatics.com/showthread.php?t=952888)

OoiRingo 10-28-2012 01:02 PM

Brakes stay engaged and grind after releasing brake pedal - any ideas?
I can't see that something like this has been discussed before, but maybe I'm not using the right search terms. Here's what happened.

I was driving downhill on a slight slope and stopped at a light. When I lifted my foot from the brake pedal, and before pressing the gas, the car started rolling forward, but one of brakes, I think the front driver side, continued to hold and made a grinding sound, then it would release then grab again with the grinding sound, 2 or 3 times, for about 10-20 yards.

I turned right and drove around the block to test the brakes, and they seemed fine until I got back to the slightly sloped stretch. The same thing happened three times on the same slightly sloped part of the road.

I had the car towed to the shop, and I'd appreciate any ideas you guys might have that I can discuss with the mechanic on Monday.

2004 330xi, automatic, no mods
As for maintenance, new front pads and rotors, and a brake fluid flush were done in July 2012.

Thanks for your help.

Zell 10-28-2012 01:05 PM

Seized caliper. Either rebuild it yourself or go to AutoZone and get a rebuilt one for $50. IMHO the price-to-labor ratio of buying a rebuilt caliper vs. doing it yourself is completely worth it. That'll solve your problem.

You should do both since they're a pair, but you can get away with one if you want.

jdstrickland 10-28-2012 01:16 PM

You are describing a binding caliper. You have an xi, so you could have an unrelated problem to the brakes that is really about the front drive train. An inspection of the front end of the car should uncover the problem.

I'm not in complete agreement with Zell, I think that if you replace one, you should replace the other.

Having said that, cleaning the pins that the calipers ride on, and cleaning the holes that the pins go into will go a long way to correcting a sticky caliper most of the time. If the problem is the brake caliper or the front drive train, it will require taking the tire off to see. Since the car went to the mechanic, there's not very much you can do with it now.

sammk 10-28-2012 02:44 PM

A lot of the times it could be the hose supplying the fluid to the caliper. If the hose is degraded from within, the fibers will act as a sort of valve and block the return of the caliper.. So that's the next item to replace if the calipers don't fix it..

WALKD U 10-29-2012 12:29 PM

caliper need to be rebuild or replaced...

OoiRingo 10-30-2012 01:17 AM

Well, the mechanic hasn't been able to recreate the issue, and they say that the brake system checks out. One suggestion they have is that a rock or other obstruction caused the issue and the obstruction is now clear.

It seems to me that an obstruction would continue to cause the problem on the uphill and flat part of the road as well, not just the downhill part. I can't figure out why the one downhill part consistently caused the grabbing and grinding sound.

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