Ok. so I'm driving with no problems on Friday when I go to stop at a red light and the brake pedal gets really hard and it gets hard to stop. I went home and this is what I've figured out so far. Both front brakes are working but both rear aren't. I disconnected the brake fluid hose off the rear calipers and they aren't getting any brake fluid. Can this be the rear brake relay? What exactly does the relay work for? Is it the master cylinder again? Someone told me it could be the ?proportioning valve?, i'm not sure exactly what it is but what do you guys think.
Please help guys..I'm kinda stomped. :roll:
Welcome to the forum. That was me that told you proportioning valve. Hope you get it figured out.
I really doubt its the proportioning valve. What you describe is the lack of accumulator/boost pressure. The rear brakes get pressure from the same circut that provides brake assist. You have no assist, and not surprisingly no rear brakes. You are correct in assuming your front brakes are working, albeit with no power assist.
I need a flow chart for this...
Turn ignition on, is the Powermaster running? Do the solenoids click a few seconds after turning the key on? If the unit is running but making no boost there is a serious internal leak. If its not running, we need to determine why.
Possibilities, bad relay, bad fuse, bad motor, bad pressure switch. Its not super easy to determine which is which. I have to look up to remind myself of the colors, but the only way to know is to check the wires, while they are still plugged in. Not super easy. But most of the checks can be at the relay. I'll try to get around to the wires, but don't have time tonight.
Chris
I am about to order my ABS from prior...I still gotta test my motor relay, hopefully it isnt bad (more headache) :x I believe the price the guy quoted me was 464.50, now my question is is that price including the core rebate, or not including, thanx!
Well, thanks for the help and advice guys.
I went home yesterday and changed the relays, fuses, and the pressure switch (Luckily one of my buddies gave me new ones about a year ago and I kept them in case of an emergency, so I didn't have to spend a dime doing this) and it still did the same thing. I also checked the proportioning valve and that was ok. All the wires were hooked up ok and the unit was running.
So, I had a spare unit my buddy also gave me. I got so frustrated I went to my dad's house and suprisingly it took us 2.5 hours to do the job. :D
Now, I don't think we bled the unit right because this is what happens. Car brakes ok but when you brake too hard/fast the brake pedal goes down a bit and then comes back up by itself. The BRAKE light also comes on when you hit the brake pedal. Theres no easy way to explain this but that's the best I can do. Is this a bad unit also or are my suspicions correct and I didn't bleed the unit correctly?
Thanks for any help you can supply.
I just got my unit rebuilt from Prior. The Price they quoted yuo is with the core rebate. I had an extra PMIII that I sent to get rebuilt while I left the one in the car. So it was only around $465, but if I did not have one to send them, it would have cost me $565. And if they have no cores there, then you have to send them one like I did.
I have to say that Prior did a GREAT job with the PMIII. It only took about a 1 1/2 weeks from when I sent it to get it back. And I have had no problems at all. Good luck with it.