Powermaster break problems

JoeMastro

New Member
Well, ive been having some problems with my 1987 buick grand national powermaster brake system, as many people do, and I have been looking everywhere for similar problems, but I finally caved and decided to ask someone here. So, whenever I turn the ignition on, the motor pump doesnt stop running, and ive noticed that the fluid in the reservoir doesnt get pumped out, it just stays at one level. The brake light also doesnt turn off at all, even when the engine is on. We tried putting on another switch that we had from another powermaster, and the pump would run properly, but there would be this hissing sound coming from around the accumulator and the master cylinder. I really hope someone can help me out, these brake systems are so strange to diagnose. If anyone has any questions I would be happy to answer.
 
I wish I could be a help but, like most, my knowledge of powemaster brakes is extremely limited. Of course, the hissing sounds like a leak. You might need to replace the accumulator?
 
Yeah, I should have mentioned we did replace the accumulator, and it did help for the most part but for the time being, the main problem is that the motor isnt stopping on startup. I'm thinking it might be a faulty pressure switch, but I want to get some more information before I spend the money on something that wont even fix the problem.
 
Yeah, I should have mentioned we did replace the accumulator, and it did help for the most part but for the time being, the main problem is that the motor isnt stopping on startup. I'm thinking it might be a faulty pressure switch, but I want to get some more information before I spend the money on something that wont even fix the problem.
Take the problem off the car and put it in a box and put it under the bench in the garage where it belongs. Its a shit system. Wrecked my car because of it.I never had a warning until someone threw a u turn in front of me. I bent the brake pedal and steering wheel trying to stop the car. There are people rebuilding them and I have seen two rebuilt ones fail within minutes of starting the car . I put vacuum on my car. Works fine. They say the GN needs the power master.Why didnt the 89 Turbo Trans Am have it? Hydratech makes a great system but very expensive. This is just my 2 cents. Do lots of research. Good luck
 
whenever I turn the ignition on, the motor pump doesnt stop running, and ive noticed that the fluid in the reservoir doesnt get pumped out, it just stays at one level.

If the fluid level on the passengers side of the reservoir doesn't go down the pump is not pumping. Sounds like the pump is bad or possibly the bottom of the reservoir has debris blocking the pump feed line. It's the black rubber hose attached to the underside of the reservoir. You may try taking off the reservoir lid and feel around where the hose connects for any debris.

Mine got blocked by a piece of foil from a brake fluid container lid. It has worked for a few months now but it seems as if the pump is getting weak and will need replaced anyway.
 
Take the problem off the car and put it in a box and put it under the bench in the garage where it belongs. Its a shit system. Wrecked my car because of it.I never had a warning until someone threw a u turn in front of me. I bent the brake pedal and steering wheel trying to stop the car. There are people rebuilding them and I have seen two rebuilt ones fail within minutes of starting the car . I put vacuum on my car. Works fine. They say the GN needs the power master.Why didnt the 89 Turbo Trans Am have it? Hydratech makes a great system but very expensive. This is just my 2 cents. Do lots of research. Good luck

X2 on that
 
If the fluid level on the passengers side of the reservoir doesn't go down the pump is not pumping. Sounds like the pump is bad or possibly the bottom of the reservoir has debris blocking the pump feed line. It's the black rubber hose attached to the underside of the reservoir. You may try taking off the reservoir lid and feel around where the hose connects for any debris.

Mine got blocked by a piece of foil from a brake fluid container lid. It has worked for a few months now but it seems as if the pump is getting weak and will need replaced anyway.

I could try that, the thing that throws me off is that when I press down the brakes real hard with the ignition on, the pump starts to work and drain the fluid out of the reservoir but thats when the hissing/leaking starts. at this point im just considering taking that piece of junk out and put a hydroboost on it or something. its just a pain.
 
seems I am uploading the powermaster service manual and diagnostic chart often these past few months. maybe search is not pulling up the other recent threads on powermaster or accumulator service?

before you switch braking systems...read through these below. You can always send yours to Mr. Clark for a rework at RCG. And get your specific powermaster unit back in the car if you have an orginal, unmolested survivor.
 

Attachments

  • PowerMaster_Flowchart Diagnosis.PDF
    39.7 KB · Views: 128
  • PowerMaster_Service Manual.PDF
    701.6 KB · Views: 117
Internally leaking most likely, or the pump isn't pumping. If the pump is pumping, you can expect to see the fluid flowing to the return port in the bottom of the reservoir side. That means the pump is moving fluid, and it's just leaking through the booster and right back into the reservoir. Also look for info on cleaning and polishing the check valve.
RCG and Kirban sell a decent seal kit to rebuild the booster end of the unit as well as replace the reservoir gaskets. A larger Hydac accumulator and a new switch and it'll be back in shape (as long as the pump is still OK). Easy to rebuild at home if you find the exploded diagrams and tech manual, and keep it all clean and lint-free during reassembly. (use compressed air)

Fresh fluid once a year, and store the car with the unit de-pressurized (pumped down) and it will last a very long time.
 
.
 

Attachments

  • powermaster.jpg
    powermaster.jpg
    152.1 KB · Views: 165
.
 

Attachments

  • powermaster power valve applied.png
    powermaster power valve applied.png
    105.5 KB · Views: 127
  • powermaster power valve released.png
    powermaster power valve released.png
    204.5 KB · Views: 108
Take the problem off the car and put it in a box and put it under the bench in the garage where it belongs. Its a shit system. Wrecked my car because of it.I never had a warning until someone threw a u turn in front of me. I bent the brake pedal and steering wheel trying to stop the car. There are people rebuilding them and I have seen two rebuilt ones fail within minutes of starting the car . I put vacuum on my car. Works fine. They say the GN needs the power master.Why didnt the 89 Turbo Trans Am have it? Hydratech makes a great system but very expensive. This is just my 2 cents. Do lots of research. Good luck

X2 on that

X3. I’m sure they can work properly but I almost crashed my first turbo Buick many years ago when that damn thing decided it would fail with no warning. A few years ago I bought my GN with 40k miles and all stock so I figured I would try to keep the power master. Same thing happened. If you’re not going to drive the car keep it but if you’re gonna drive it then I would find another brake system


Sent from my iPhone using Tapatalk
 
Well thanks for all the info guys. I'm going to try out some of these things this week and see if anything works itself out.
 
I'm still trying to figure this out, but I had an idea. I was going to ask if anyone had the time to post a video or something of their Grand National's brake pump working properly so I can hear and see what its supposed to sound and look like. Maybe just putting the car in the run position for a minute so I can get some more info. I'm not sure how posting videos works on this forum but if its possible, I would really appreciate it.
 
OP, I applaud you for trying to get this worked out. I've been there. But after the PM tried to kill me a few times, including once with my son in the car, I decided it was more useful as a boat anchor. Went hydroboost.

Good luck. You'll get it fixed. I pray when it goes out again, and it will, you're just backing down your driveway.


Sent from my SM-G965U using Tapatalk
 
OP, I applaud you for trying to get this worked out. I've been there. But after the PM tried to kill me a few times, including once with my son in the car, I decided it was more useful as a boat anchor. Went hydroboost.

Good luck. You'll get it fixed. I pray when it goes out again, and it will, you're just backing down your driveway.


Sent from my SM-G965U using Tapatalk
I hear that.
 
If your car is close to stock a vacuum setup will work fine and you can switch over for about the same as any one part of the power master. 1/2 or 1/4 the price of some of the parts. The 1989 TTA came with vacuum brakes and for a street car vacuum is the cheapest option. The hydro boost is a better upgrade but more expensive. If you have a big cam that doesn’t provide a lot of vacuum then hydro boost would make sense. If you are not going to drive the car at all then it makes sense to keep the power master and try to fix it. The last time mine went out it gave me no warning at all and the idiot light “brake” only came on after the power master failed and I almost ran into the car in front of me. It had worked fine for 6 months with zero issues on a 40K mike car before this incident. 20 years ago I had one do the same thing but the car had 100K miles. I bought pressure switches, accumulator balls and finally a car done unit with a lifetime warranty. The lifetime warranty unit failed and when I took it back they said they didn’t make them any more so they refunded my original purchase amount. If you’re going to drive one of these cars with a power master make sure you have full coverage insurance with a agreed upon value policy.


Sent from my iPhone using Tapatalk
 
Top