The brake light came on and off the last time I drove my 87 T. So, I did the accumulator check -
depressurized the brake system by pumping the brake pedel 10 times, then timed the required time for the brake light to go off with the key turned to the on position. The standard is 2 to 7 seconds. My brake light remained on for 10 to 12 seconds (I tested it a couple of times). I believe this indicates a bad accumulator. I left the key on for an additional 2+ minutes to see if the system self-cycled indicating an internal leakage in the powermaster itself. The system did not self-cycle in the two minutes but right after the 10 to 12 seconds after the brake light went out I heard an electrical clicking a few times. The motor/pump never went through a self-cycle. I guess this was the relay inside of the motor for the pump? Any suggestions of what the electrical clinking is and is it of any concern? Any suggestions on what to replace first? I replaced the original accumulator with a new style back in 94.
Thanks for any suggestions, Craig Powell
Well, I changed the accumulator and that cured my brake light. I also checked for the clicking sound. I heard the clicking a few times after the brake light went out while performing the accumulator test. So, I swapped in a know good brake switch from a friend (thanks DDAy). The clicking never happened again with his switch. I reinstalled my switch and performed the test 4 more times. The relay clicking never happened again. So, I am just going to monitor the clicking of the relay. If it happens again I will replace the switch.
Craig
Where would be the best buy on that accumulator.
I think mine is shot also.
Check the TR vendors and discount GM parts sources listed on the site.
http://www.gnttype.org/vendors/
http://www.gnttype.org/vendors/gmparts.html
I have similar problem. Right when I put the brake on just for an instant the brake light comes on and goes right back off. I have not had the car but for a couple of months and only been able to drive it a few times but this happens every time I hit the brakes.
I just bought an 87 GN and the brake light goes on whenever I press down the brake pedal and braking is very reduced. Should I bleed the system to see if there is air in it? Could it be the accumulator?
You need an accumulator ASAP. Don't drive it until you replace it. The max run time on the pump motor is 30 seconds and then a long rest. Longer run time will burn it up.
Ok, hate to add to the mayhem, but my 87 GN was making noise like it had a vacuum leak somewhere around powermaster unit. 130 miles later, brakes went out and brake light came on. Now brakes come and go...but whenever brakes don't work, brake light always comes on. Sometimes they don't work for a few minutes...sometimes longer.
Oreilly's salesmen were a bunch of idiots. Powermasters rebuilt online listed for $389.00 plus $100.00 core charge. What should I buy or try first? If so where should I get it? Gregg
I've been reading all the recent messages about brake problems, and now I have my own. I am rebuilding an '87 T-Type I had bought with a blown engine. I recently finished putting another engine in it and started it first time a couple days ago. I had bled the brakes before - till clean fluid with no bubbles came out the bleeders, and the pedal was hard with the engine off. But when I got it running, and applied the brakes, the brake light came on and the pedal slowly went down to the floor, at which time the brake light went off. I did this repeatedly, same thing each time. I do have some braking; I took the car out my drive to check the transmission, and could stop the car, but the pedal always goes slowly down to the floor. When I turned off the engine, the pedal is hard again.
I did the check of pumping the pedal 20-30 times, then turning on the key. The brake motor ran only about 5-7 seconds before shutting off, so does that mean the accumulator is OK?
Also, there is a connector coming out the top of the power brake unit, and it is gray; is this the thing that had a recall notice on it that I have read about? Can someone explain to me what the recall was for and how I can tell if this unit has had it replaced?
Any help on these two items would be appreciated.
Thanks
My brake red light comes on for a second when I press the brake pedal, then turns off. Pedal feels normal, no other signs of problems, but the car is now parked until I figure it out. Any ideas? Please e mail me if you don't mind helping a fellow "Girl" GN Owner/Do it yourselfer! stevens66@aol Thank You!
I moved the preceding article here, since it just didn't seem to belong in the "Oil in my intercooler" thread.
Parking it is a cautious, but safe bet. Likely to be a worn-out accumulator bulb on the Powermaster brake system. Easily fixed. See http://www.gnttype.org/techarea/brakes/brakespage.html Looking at all the info we've assembled on this site over the past dozen years, you just might find a few answers. There are some simple diagnostic procedures (really no more that counting how many seconds the pump motor runs between applications while parked, etc.) to test the system. Parts available from many sources on our vendor pages.