1998 Pontiac Grand Am Very hard grabbing brakes

LOSTDAYWALKER

MEMBER
1998 PONTIAC GRAND AM
4 CYL
FWD
AUTOMATIC
141,000 MILES

I have read previously asked questions and I would like to make sure I'm on the right track. I have a 98 grand am gt with 141000 miles and have had zero problems with it until now. (Besides usual wear parts) The rear brakes would grab after sitting for a while. Pump the brakes a few times before you take off and they behave fine. Today, in only in drive, the rear brakes grab so hard that the rear of the car will squat down until released. This happens only in drive and not reverse. GM service manual does not cover this situation. Am I on the right track by replacing the rear shoes, drums and adjusting hardware. Its all original minus shoes. Since I'm there should I replace the rear wheel cylinders as well? Will this solve the problem? Rubber o-ring for vacuum to the booster needs to be replaced as well (slight leak). Thanks Sean

4 Replies

SERVICE WRITER

MECHANIC
9,123 POSTS

HEy Sean,

I'll bet that when you pull the drums your going to find the wheel cylinders have started leaking and the shoes are now coated. My guess is the brake fluid is down a bit.

Get a couple cans of brake clean to spray them down so you don't have to work in the muck.

Shoes, hardware, machine or replace drums and wheel cylinders is what I would anticipate. GO out and spray the line going into the wheel cylinder with penetrating fluid ASAP so it has a fighting chance of coming off.

Buy a set of high quality shoes, not the mid grade or cheap ones.

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Tuesday, August 19th, 2008 AT 5:30 AM

LOSTDAYWALKER

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2 POSTS

Thanks for the response. PB Blaster is my best friend. Since I've never had this happen before, I wounder if it relates to a part that I've never had to change before. The power brake booster. My daughter had reported that the brake pedal had been very firm at times. Since it appears to be both rear brakes grabbing hard enough to squat the rear end down, I'm beginning to think there may be a cause other than the usual leaking brake cylinders. I'm going to do the rear brakes anyway but would like to be sure ( if you ever can be), I solve the problem.

Thanks Sean

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Tuesday, August 19th, 2008 AT 1:16 PM

STILLNMONTANA

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1 POST

Sean, I feel your pain. My car has the same set up but with 122,000 miles on it. I have been fighting the exact same scenario since i've owned the car with 28,000 miles. I've cleaned every thing with brake clean and installed new shoes with no luck.

I think there are two possibilities: one being the automatic adjusters. I noticed that right after I did the brakes that they worked perfect for about a month, but it's back to squatting at a stop. Try backing up and repeatedly firmly braking. (This forces the automatic adjusters to rachet the brakes tighter to the drums.) Or its supposed to.

Second problem may be air in the system. My wife is terrible in the garage and with her help, I can't say that i've completely bled the air out properly. I just read that the ABS module may also need bled, so that will be my first try tomorrow night. I'll keep posting to let you know what I've found.

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Monday, August 25th, 2008 AT 10:58 PM

SERVICE WRITER

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9,123 POSTS

Just to emphasize, I have run into this with low end shoes. Our solution was Wagner or Bendix riveted shoes. Their top end ones. And hardware.

Wouldn't hurt to check the master cylinder for swolled rubber, this can be a sign of contamination that can affect wheel cyls and brake hoses.

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Tuesday, August 26th, 2008 AT 8:04 AM