brake problems..(warning light)

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caferacerx said:
it is a pressure differential switch, it is designed to sense an imbalance between the front and rear brakes, the switch needs to be centered in order for the light to go out, after you replace the master cylinder and bleed the brakes, have someone open one of the bleeders (front of you bled the back last) and very gently press the brake peddle until the light goes out, if you go to far or nothing happens go to the other end of the car (back to front not right to left) and try again
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what order do I do this then? got a little confused reading your post..
 
caferacerx said:
it is a pressure differential switch, it is designed to sense an imbalance between the front and rear brakes, the switch needs to be centered in order for the light to go out, after you replace the master cylinder and bleed the brakes, have someone open one of the bleeders (front of you bled the back last) and very gently press the brake peddle until the light goes out, if you go to far or nothing happens go to the other end of the car (back to front not right to left) and try again
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Like mentioned above, have someone step on the brake while you crack a bleeder slightly, if the light goes out your done, if not go to the opposite end of the car and do the same. Your trying to move the switch to a non ground position.
 
SGBARRACUDA said:
Like mentioned above, have someone step on the brake while you crack a bleeder slightly, if the light goes out your done, if not go to the opposite end of the car and do the same. Your trying to move the switch to a non ground position.
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it was unclear in caferacerx's post though as to which one to start on. I start on one of the rear ones, and them move to one of the front ones?
 
fredsmedina said:
alright. well hopefully the master isn't my problem. any idea how i'd know if it did have an internal leak? because if you hold the pedal at a certain point, the pedal will "loose pressure" meaning my foot will just keep going down.
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Sorry for not getting back to you but it looks like the other guys are getting you to a solution.
Just to clarify the internal leak thing for future readers - the behavior of the pedal will be something like it will slowly go all of the way to the floor or it may stop and get firm again if the seal finds a good spot on cyl bore.
My symptom was that the pedal would start to fade if I held it at a particular point then firm back up when it got further through the travel. It then quickly deteriorated to total loss of pressure within a couple of days where the pedal would just completely fade to the floor ( couldn't pump up the system at all like with air in the lines ) I never did get to tear that one apart to see what the problem was...just returned it for a different one.

As for the parking lever not turning the light on...I'm looking through the wiring diagram and it appears that the switch for the parking brake does not rely on the wire from the prop valve. Maybe the parking brake switch isn't touching the arm.
 
player1up said:
Sorry for not getting back to you but it looks like the other guys are getting you to a solution.
Just to clarify the internal leak thing for future readers - the behavior of the pedal will be something like it will slowly go all of the way to the floor or it may stop and get firm again if the seal finds a good spot on cyl bore.
My symptom was that the pedal would start to fade if I held it at a particular point then firm back up when it got further through the travel. It then quickly deteriorated to total loss of pressure within a couple of days where the pedal would just completely fade to the floor ( couldn't pump up the system at all like with air in the lines ) I never did get to tear that one apart to see what the problem was...just returned it for a different one.

As for the parking lever not turning the light on...I'm looking through the wiring diagram and it appears that the switch for the parking brake does not rely on the wire from the prop valve. Maybe the parking brake switch isn't touching the arm.
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thanks for that clarification. I don't think that this is my problem now, but it should help out future readers like you said..
and as far as the parking brake, i'm not too worried about that light turning on for the park brake. I know when its in and when it isn't. thanks for looking into that though. I've got my wiring diagram and service manual on the way to me in the mail right now too..

64conv65hard said:
Well, was the problem found? Fixed? What did you find out?
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I'm pretty sure the problem is the prop valve. and should be fixed by resetting it as stated above. just been real busy with work though. and haven't got a chance to get to work on it yet..

tomorrow is my 1st day off, but i'm going snowboarding for the very 1st time. Then I work saturday sunday monday, so definitely next tuesday i'll be getting out there and figureing it out!
will update post as soon as i do it..

thanks everyone so far for all your help!

one last thing, the warning light will every once in a while blink off every since I stomped on it like 64conv65hard had told me earlier..so does this mean anyting? This still means it could be the prop valve being stuck to one side right..?
 
i'm confused..The light has been on since I bought the car. It just turned off today randomly when I started up the car leaving work. it stayed off for about 10 mins. and then turned right back on..still haven't had the time to try bleeding it to reset the prop valve..i need to do that asap though
 
fredsmedina said:
i'm confused..The light has been on since I bought the car. It just turned off today randomly when I started up the car leaving work. it stayed off for about 10 mins. and then turned right back on..still haven't had the time to try bleeding it to reset the prop valve..i need to do that asap though
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Seems like it is trying to center. If after bleeding you still have a problem you may need to replace the switch or the whole valve.
 
Just a thought, did you bench bleed your master cylinder prior to installing it in the car?
 
SGBARRACUDA said:
Where the wire plugs onto the valve, the switch unscrews.
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oh alright. thanks..will update thread once i bleed it..

halfhemi said:
Just a thought, did you bench bleed your master cylinder prior to installing it in the car?
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and I don't believe so. I actually was planning on power flushing the entire system, so when I went in for the power flush, I brought a new master cylinder with me, and had them instlall that as well. So I just had the shop do the power flush and master cylinder swap all at once. didn't want to swap the master cylinder myself and contaminate it with the old fluid..
 
so i was all set to spend all day tomorrow working on the satellites brakes, and when i started up the car today, no brake light on!

soo did it fix itself? or did the switch go out? brakes seem to be working great still...
 
There is a possibility that it did "fix" itself. If the piston inside the proportioning valve was stuck with crud from the old fluid, it might have freed up from the new fluid flowing past....
 
player1up said:
There is a possibility that it did "fix" itself. If the piston inside the proportioning valve was stuck with crud from the old fluid, it might have freed up from the new fluid flowing past....
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thats what I was thinking..wasn't sure if that made sense though..we'll see if it turns back on. seems like this whole thread would be a waste if problem is fixed now..

i learned quite a bit though about prop valve and stuff..
 
Glad to hear that it freed up without having to tear to many things apart. Sometimes you get lucky like that.
 
Thanks for the info here guys. I started a thread last year about my light turning on when I applied the brakes. I need to take another look at it. :angry7:
 
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