serious brake problems in 98....lock up/skid

[zachzchw]

My wife has a 98 grand am se.......
The ABS system is messed up, when you brake, and stop, it lets up, so you coast forward a bit.
So her dad unhooked that, so its just using regular (non abs) braking.
When stopping, it locks up, and you skid a little ways- sometimes worse than others. Sometimes youll slide up to 10 feet. It happens on wet pavement, dry pavement, doesnt matter.

Pads, rotors, and drums have all been replaced.
Any thoughts on what it might be? Im very worried about my wife and my three month old baby in that car, I dont want the brakes to just like completely fail.

Thanks for any help.

[GTP Dad]

Take the car to a mechanic and have it repaired. The antilock brakes are not completely disabled and causing the brakes to lock for a period of time. I know it may be expensive but there is a possibility of complete brake failure if you don't. I also don't know what he unhooked but it may have been just the light and the antilocks are still active. Get them checked by a professional.

[zachzchw]

Originally Posted by GTP Dad

Take the car to a mechanic and have it repaired. The antilock brakes are not completely disabled and causing the brakes to lock for a period of time. I know it may be expensive but there is a possibility of complete brake failure if you don't. I also don't know what he unhooked but it may have been just the light and the antilocks are still active. Get them checked by a professional.

The antilocks are definitely unhooked.
Theres a very big difference when it is hooked up and when it isnt.
I really cant afford to take it to a professional, I can just imagine the bill. My father in law and I can usually do most things ourselves, we just need to know what to look for.

Thanks for the help!

[GTP Dad]

If you can't afford to take it to a professional then check to make sure the lines to the brakes aren't pinched or twisted. That can cause locking also make sure that you are getting equal pressure to each side of the brake system. With antilocks the pumps restrict flow. If the sytem has unequal pressure due to the system being disengaged then you can get locking from one caliper or the other or front to rear.

[Slade901]

It's probably the ABS itself and need to be checked out at a dealership. You can get a diagnostics for it first and then see how much it will cost you. Some repair shops will wave the diagnostics fee if you have them fix it.

One thing you can check is the ABS wheel speed sensor. Either that speed sensor is full of crud where it is blocking the speed sensor ability to check if the wheel is locked up or not. It's usually have a magnet on it and over time it will accumulate some metal shavings and just try to clean it. Check the wires on the ABS speed sensor to make sure it's not nicked or rubbing in a metal/ground.

[zachzchw]

Originally Posted by GTP Dad

If you can't afford to take it to a professional then check to make sure the lines to the brakes aren't pinched or twisted. That can cause locking also make sure that you are getting equal pressure to each side of the brake system. With antilocks the pumps restrict flow. If the sytem has unequal pressure due to the system being disengaged then you can get locking from one caliper or the other or front to rear.

My father in law did mention that- but he said to replace the other stuff first- so I guess Ill go to autozone and pick up the brake lines.
Should I only do the ones that are faulty, or should they all be done at the same time?

[GTP Dad]

The first thing to do would be to pull each wheel and make sure that none of the lines, rubber, are kinked or twisted. This can happen when you put on new brakes. If one is kinked it could cause the problem you describe and will not cost anything to fix. As for the lines they can be blocked or damaged but I would start with the front, probably easier to replace. The rear lines will be harder to get to and will take a lot longer to replace.

[zachzchw]

Bringing this back up in hopes of more suggestions.......we have now tried the brake lines.
Its been in three repair places, none of them can determine the cause of the problem. Each time, they have "adjusted" the brakes, and it works fine for a week or so, then starts doing it again.
Any other thoughts on this?

[zachzchw]

It was suggested that the backing plates be checked. They are fine.
What else to look at?

[xeroinfinity]

Has either of the rear wheel cylinders been replaced?