Please help me!
My 93 Brake pedal started to get spongy and would go all the way to the floor. The ABS light was intermittant but now is on all the time.
I bled the rear brakes (black guk came out). Havn't done the fronts yet because I need two new bleeder screws ( I stripped them).
I read related posts and:
- tried the paper clip trick on the EH valve unit, test OK.
- Unplugged the connector to the RABS unit, no change.
- Tried adjusting rear brakes adjusters braking backwards, no change, I also had a shop adjust them 5 months ago. When I got it back the pedal was nice and hard, maybe only two inches of travel. But now it seems to have diminished.

I tried to find the connector to get codes but could only find one behind fusebox that had four wires going to it like a black box. Am I looking in the right area? How can I tell if the MC has failed? or what other componant it might be. Anything you folks think that I have overlooked? Please help me
Andrew

 

Since you have residue in the system, the first place to start is a thorough flush and bleeding of the brake system. Replacement bleeder screws are usually available at most parts stores. You need to bleed the system to establish a baseline before pursuing other problems.

 

Well Andrew are you ready to work? The connecter your looking for I believe is behind the passenger side kick panel. Single connector with red wire on 1 side and black with red strip on the other. Disconnect and with key to on position, ground black w/red strip wire briefly. ABS light should flash, count the flashes and that is the code.Let us know. To clear code, turn off ignition while connecter is unplugged, plug it back in. #2 usually if a MASTER CYLINDER FAILS there will be fluid leaking at or wet looking at the mounting area of the booster. Underneath the cylinder. Not always the case though. Manually adjust the rear brakes (by hand). tire up in the air and slight drag when you rotate the tire. Let us know how it goes and we'll help some more. Good luck ok.

 

afcro,

Did you find out what was causing your brake problem?

Ron

 

Well Ron, the weather hasn't been co-operating and time is tight before Christmas, so I took it to my local mechanic today.
He found a few problems. One of the front pads was cracked in half (overheating) and the rear adjusters weren't properly connecting.
He also flushed out the old fluid and replaced the bleeder screws that I rounded. The brakes feel great now. The pedal only travels two inches and not all the way to the firewall. Oh, and yes, the gosh darnn abs light is still on after all that. He ran a diagnostic test and found code 12. The "ABS controller". I kind have suspected to be this. So I'm going to the local bone yard close to me to get a replacement. I have a question though. Is it the black box mounted to the left of the tranny hump, driverside, just under the dash? And will one from a 93 or newer matter or should it be the exact one?

Thanks Ron & Aerocolorado!!!!
-Andrew.
P.S. Merry Christmas to all!!!!

 

Thanks to you also Luckild!!!

 

afcro,

I'm glad that you finally had the system flushed and, if you had a front pad that overheated enough to crack, then you probably are not using your rear brakes at all. In this event, you either have a major problem with the rear brakes (ie a leak in the system, a bad rear cylinder, etc.) or your controller is bad. First, I would check the rear brake system to find out if the problem lies there.

The reason I say this is because I have not seen a post here that ended up being the ABS controller. Therefore, I'd check the pressure being delivered to the rear system before I trashed the controller. You might have a clogged line causing excess pressure being reported to the controller and cutting off the brake pressure to the rear brakes. Also, you could have air trapped in the controller making it appear to the system that a low pressure condition exists thus cutting off pressure to the rear brakes. (Especially since you had trash in the system)

Please remember that the code reported by the system is only an indication of what MIGHT be causing the problem. It is a place to start troubleshooting from. Before I changed the ABS controller, I'd check the following:

1. The pressure being delivered to the front and rear brake systems, and
2. The condition of the proportioning valve. (It could be stuck in a position that doesn't allow pressure to the rear brake system)

I don't want to sound like I don't trust your mechanic, but I've learned over the years that most of todays mech's are parts changers and not system troubleshooters.

LOL and Have a Merry Xmas to you and yours.

Ron

 

afcro,
While at the boneyard you should also pick up the RABS solenoid valve assembly from the same vehicle. As rimdad noted, the controller has, to date, never been found to be the problem. Generally, in neglected brake systems, the water contaminated fluid causes valve corrosion in the solenoid assembly which in turn can generate all sorts of error messages.

 

I will let you all know as the SAGA continues....Thanks again!-Andrew