Brake Question

[RJolly87]

I have noticed that the left rear brake loves to lock up. It doesn't do it under casual braking conditions, but if something is slippery, or i have to jump on the brakes, it is almost always the wheel that triggers the ABS. Is this normal? Do these cars have a little bit stronger rear bias? Any suspicions as to the cause? Master cylinder was replaced in April, and the rear brakes were last adjusted then, and all 4 corners were bled as they should have been.

Ideas?

[myfirstbonnie]

Possibly not adjusted even with the other side. The automatic adjusters on the rear drum set ups are known for getting stuck and not adjusting properly.

[teleplayer]

I don't think it is an adjustment problem.

If the wheel cylinder has even a very small leak, it will get on the shoes and cause the wheel to lock up. You won't see this leak from the outside. In fact, even with the drums off it may not be apparent. Check for wetness near the rubber boots on the wheel cylinders, and check for excessive rusting of the backing plate.

Some other signs that you have a brake fluid leak are: 1) Wheel locking up on the first couple of brake applications, and then ok after that. 2) Wheel tending to lock up more easily on a damp / rainy day.

If you are not sure, completely wash everything under the drum. You can do this outside using a garden hose. Just blast it all clean, let it dry and put the drum back on. Drive for a week or so, then open it up and see if brake dust is hanging onto (wet) areas around the wheel cylinder.

Grease leaking onto the shoes will also do this, but this was more of a problem on rear wheel drive axles, and not with the sealed bearings.

[Roadtech195]

Possibly not adjusted even with the other side. The automatic adjusters on the rear drum set ups are known for getting stuck and not adjusting properly.

Xs2 agrees 100%
Also check the adjustment by jacking up the rear of the car, now spin the wheel by hand a few times. There should be a slight and steady drag as you spin the wheel, barley even noticeable drag is perfect. Any change in resistance while spinning would suggest your drums are out of round and need to be turned or replaced.

[teleplayer]

If one rear brake is adjusted differently from the other, you will not get any braking until both sets of shoes (left and right hand) touch the drums, at which time the pressure in the lines will then increase enough to put some force against the drums. At that point, the adjustment is out of the picture.

[Bugsi]

Possible rusted / stuck parking brake? At least check it. I've had the parking brake cables bind up from rusting before in previous cars.

[RJolly87]

I don't think it is an adjustment problem.

If the wheel cylinder has even a very small leak, it will get on the shoes and cause the wheel to lock up. You won't see this leak from the outside. In fact, even with the drums off it may not be apparent. Check for wetness near the rubber boots on the wheel cylinders, and check for excessive rusting of the backing plate.

Some other signs that you have a brake fluid leak are: 1) Wheel locking up on the first couple of brake applications, and then ok after that. 2) Wheel tending to lock up more easily on a damp / rainy day.

If you are not sure, completely wash everything under the drum. You can do this outside using a garden hose. Just blast it all clean, let it dry and put the drum back on. Drive for a week or so, then open it up and see if brake dust is hanging onto (wet) areas around the wheel cylinder.

Grease leaking onto the shoes will also do this, but this was more of a problem on rear wheel drive axles, and not with the sealed bearings.

Interesting, because that describes the issue pretty accurately. Especially the first starting out part. That wheel locks up coming down the driveway at work when leaving. Makes for an interesting show.

[wjcollier07]

I don't think it is an adjustment problem.

If the wheel cylinder has even a very small leak, it will get on the shoes and cause the wheel to lock up. You won't see this leak from the outside. In fact, even with the drums off it may not be apparent. Check for wetness near the rubber boots on the wheel cylinders, and check for excessive rusting of the backing plate.

Some other signs that you have a brake fluid leak are: 1) Wheel locking up on the first couple of brake applications, and then ok after that. 2) Wheel tending to lock up more easily on a damp / rainy day.

If you are not sure, completely wash everything under the drum. You can do this outside using a garden hose. Just blast it all clean, let it dry and put the drum back on. Drive for a week or so, then open it up and see if brake dust is hanging onto (wet) areas around the wheel cylinder.

Grease leaking onto the shoes will also do this, but this was more of a problem on rear wheel drive axles, and not with the sealed bearings.

Agree 110%. This is also sometimes evidenced by finding dried puddles of goo in your wheels...and usually this is what appears when the problem becomes large enough to make lockups happen.

Change wheel cylinders, bleed and adjust brakes and you should be golden. Leisurely done, its about a 1.5-2 hour job, but done under time, could probably be accomplished in about 45 mins

[LeSabre in Buffalo]

Good time to get a pressure bleeder.