Bad brakes.

Guest · Post by **Guest** » Wed Sep 27, 2006 12:37 pm

Hey Guys,

My name is Justin. I just bought a 1994 Baretta from a friend of mine so could have a winter car. Its red with the 3100 V6, and automatic. The car has all the power options including ABS brakes.

So, that brings me to my questions. The ABS system is pretty screwed up. When the car is at idel speed, and the brakes are applied, the rear drums lock up and the back tires screech. I took the drums off and checked the shoes but my friend was right, the brakes were changed only about a year ago. The front rotors work fine. I have had the car up in the air several time trying to see what happens. Also, then the tires screech and lock up the rear end of the car sinks down. And when in revears the rear of the car rases up when the brakes apply. Another interesting thing is the brakes don't lock driving backwords.

I am a decently sound guy when it comes to working on cars. I do all the work on my 5.0 Mustang GT, but I have to admitt, has me stumped.

Any help, or ideas would be appreciated.

chevythunder · Post by **chevythunder** » Wed Sep 27, 2006 7:40 pm

make sure the shoes were put on right . Short linning on front and long linning on the rear. Is the ABS light on ?? That can cause the same problem.

Guest · Post by **Guest** » Wed Sep 27, 2006 10:04 pm

Yeah the Shoes are fine. Done by a mechanic my buddy says he always uses. I dunno. The ABS light is not on. It works though we disconected the abs sensor and it went on, we put it back on, it went off. Im stumped still.

Thanks though.

docrodg · Post by **docrodg** » Thu Sep 28, 2006 12:11 pm

sounds like the rear brakes due to the reverse working ok. rear drums are direction-specific in that they are really activated by the wheel turning. Sounds like they are applied hydraulically all the time. Look for a problem in the pipes or master cylinder valve. Also try checking the brake booster, the internal spring and baffle could be bad causing a vacuum lock up. If just the rear brakes are locking that explains the butt rise in the car. If it is just the rear you can verify by opening the bleeders and then trying it, that will isolate a hydraulic issue. Also check the p brake adjustment, could be a little tight, giving it pressure to activate the shoes when turned.

Full diagnostic (off the top of my head, and without coffee in me):

Get the car up in the air and wihtout the engine on try spinning the wheels, there should be no drag on the rear and front. Place the key in run but don not start the engine and check again, problems there are in the ABS unit. Then start the engine and check yet again, problems are now abs or vacuum boost. Disconnect the abs system to see if it locks up while running and in drive and try again and if ok the abs is fried. Shut it off, apply the brakes and start it, pedal should sink from the vacuum boost.

Another thought, if the master cylinder was changed it could be too close to the booster and need shimmed, this will cause a full lockup as the pin presses the cylinder piston.

stang&2Birds · Post by **stang&2Birds** » Sun Oct 01, 2006 5:28 am

What year Stang?

It's very unlikely the ABS! To be sure, with the ignition off, disconnect one of the wheel sensors. This will light up the ABS light and disable the ABS.

Another problem could be the TIRES! For just about ALL ABS systems, ALL FOURS TIRES MUST BE 100% EXACTLY THE SAME! Same size, type, wear, etc. If not, ABS problems can occur.

At *what* speeds do the rear brakes lock up? I assume they let go when you start again. Can you do 10mph and the slow down very gradually with the brakes without a lock-up?

Decipha · Post by **Decipha** » Mon Oct 16, 2006 10:41 pm

check your brake lines for the front brakes, i wouldn't doubt if they are rotting, i remember my car used to dip in the rear when i hit the brakes, i changed my front brake line off the caliper which i noticed was starting to crack but wasn't leaking... needless to say no more rear dip

docrodg · Post by **docrodg** » Thu Oct 19, 2006 9:59 am

You likely had an internal rot on the line too, Decipha. A small piece of hose flaked inside but was still attached on the bottom and when you pressed on the brake it caused a block in the line, thus preventing more fluid to that caliper. Release the brake and the sliver allowed fluid back up. This can happen with rotting lines or lines that are damaged by hanging the caliper by them or other goofs during maintenance, not often, but it does happen.

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