Another brake problem

jasonrush · April 26, 2009, 06:37:12 PM

After scouring the forums for an answer i've decided to just ask. I have the red(orange to some people) brake light which stays on all the time and the anti-lock brake which flashes after a few minutes of the car being on. When I turn the ignition to on(engine off) I can hear the pmIII unit continulously hum. I am still able to brake but does not feel like I would be able to stop in an emrgancy. An suggestions on which part might need to be replaced?

R Dubya · April 27, 2009, 01:57:07 PM

blinking anti lock means that you have brakes, but no anti lock. the red light usually means something worse. you are looking at replacing or repairing/remanufacturing your current powermaster ABS master cylinder.

there was a thread around here recently about a place to have it done or something on ebay I think. you should be able to find it but I'm sure someone can point you in the right direction.

Prospeeder · April 27, 2009, 03:43:57 PM

Have you checked the fluid level? the pump doesnt stop ever? Could be stuck relay? Better stop driving it like that, youll burn up the pump. Maybe even a completly dead accumulator?

TGP Nick · April 27, 2009, 08:01:47 PM

The red BRAKE light means your parking brake is stuck on. Your parking brake mechanism is likely gunked up and/or your cable(s) are rusted.

mfewtrail · April 27, 2009, 10:24:20 PM

Quote from: TGP Nick on April 27, 2009, 08:01:47 PM
The red BRAKE light means your parking brake is stuck on. Your parking brake mechanism is likely gunked up and/or your cable(s) are rusted.

The red brake light doesn't only indicate that the parking brake is on, it indicates other faults with the braking system such as a bad pressure switch, accumulator pressure below a certain level, low brake fluid, etc.

Jason, here's a page with a little more brake information: http://www.kazmotorsports.com/tpsgarage/ - click the powermaster link there.

Prospeeder · April 28, 2009, 07:05:22 PM

Quote from: TGP Nick on April 27, 2009, 08:01:47 PM
The red BRAKE light means your parking brake is stuck on. Your parking brake mechanism is likely gunked up and/or your cable(s) are rusted.

Yea go out and pump your brake pedal with the key on 5-10 times really fast, the red brake light will come on and the pump will run. Or depressurize the unit and see how many seconds it takes before the red light goes off. Or overpressurize the system, itll set off the red brake light, get the level too low, light comes on, leave the parking brake on, sets off the light, ect....

jasonrush · April 29, 2009, 02:05:37 PM

Recently we have been having some hot weather here and i had the brake problem but today it was 60 degrees out and no lights came on. The pump comes on after every brake press but it stops now. I know the red brake light had nothing to do with the parking brake because it wouldnt come on until you first pressed the brakes then it would stay on. Both of the resivoirs in the master cylinder are full. From what people have been telling me i either need to bleed the brakes or replace the accumulator. I guess i'll try bleeding first. Thanks for the help.

jasonrush · April 29, 2009, 02:22:08 PM

Do you think the heat could be causing a relay to stay open? If it is the relay are they still available?

jerry455 · April 29, 2009, 03:33:33 PM

when my relay was sticking on the car would be off and the pump would still be running. I used to keep a long screw driver in the car and if it did stick on I would tap it with the screw driver to stop it. I bought a new relay last winter and from what I was told they are no longer available, I must have got one of the last few.

Prospeeder · April 29, 2009, 11:14:40 PM

the relay is the only part of this system completly unavalible i belive

jasonrush · April 30, 2009, 07:09:58 PM

at gmpartsdirect.com under the abs section there is a motor relay...that should be it right?