Power Master Issue

[TurboWh1]

I have a odd situation.... the 30a fuse blew on the last drive in my GN. The power master motor was making a humming noise, none like I’ve ever heard. Motor was very warm to the touch. This went on for 20 minutes or so. I was being extra cautions as I was assuming the brakes were about to fail. No brake light was on when the motor was humming. The Brake light finally came on and I had about 10 stops left. I ended up limping the car home. So I replaced the 30a fuse and the motor started working. At First, the brakelight was still on. So I replaced the accumulator and brake switch with known good parts. The power master seems to be working now but not as I feel it should. The brake light is off and there are no external leaks but the power master runs every time I hit the brake pedal. Roughly 2-3 seconds. The brake light never illuminates on or off the pedal. I don’t feel this is normal. Anyone ever experienced this? Motor bad or internal failure? I’ve reviewed the info on gnttype.org. My scenario doesn’t fit the flow chart.

 

[mikestertwo]

Sounds like a bad accumulator

 

[TurboWh1]

Sounds like a bad accumulator

I wish Tried two known good ones.

 

[williamsGN]

Same issue with the fuse, sometimes fuse last for weeks... if its not the switch (swapped mine out), its the motor I believe.

 

[salvageV6]

Internal leak perhaps?, try to dig up the old threads on how it all works, leaking check valve in master?

 

[gsgnnut]

Time to ditch the pm and go hydroboost or vacuum. You won't regret it and you can put all the money you save to better use and it might even save your life. The power master is the devil

 

[TurboWh1]

I’m going to swap the power master motor and hope I get lucky. If not time for vacuum!

 

[Dennis Kirban]

kirban 2 cents worth....

Based on sales its about 50/50 pm units versus vacuum that we sell pm have become a real nite mare due to age and neglect I am having to have the windings in the motors rebuilt at another source before cardone can do them as many are now burnt up.

I can forsee units soon approach almost a grand....we are behind due to all these on going issues with them....when I was in the GTO business I never was in the brake business like I am with turbo regals....

key with vacuum is the pedal needs to be changed which is part of the kit we sell.

denniskirban@yahoo.com

 

[captndave737]

If it's running every few seconds and the accumulator is known good then it's most likely the check valve. All it takes is almost imperceptible contamination to take them out. If the motor is running it's probably not the motor.

I had a newly rebuilt unit which worked fine for a week. Then after a few days in stop and go traffic the motor started running like yours and the brakes were getting worse. Pulling into a parking garage I almost wrecked the car when they went out completely. If i had been going more than a few MPH I would have. Stopped the car with the ebrake.

I've had all 3 systems and nothing comes close to hydroboost.

 

[Ttype6]

The brake light is off and there are no external leaks but the power master runs every time I hit the brake pedal. Roughly 2-3 seconds. The brake light never illuminates on or off the pedal. I don’t feel this is normal.

You have a Powermaster that is operating as it should. Does the motor still make the unusual noise or get hot? Does the motor start with the car sitting for 15 minutes with the key in the run position?

 

[TurboWh1]

You have a Powermaster that is operating as it should. Does the motor still make the unusual noise or get hot? Does the motor start with the car sitting for 15 minutes with the key in the run position?

It’s hard to tell if the motor is getting hot. The roads are salty here in Ohio so I don’t drive either one of my Turbo Regals. I’m hoping it warms up and rains some to clean the roads off. The noise seems to be normal when the motor runs. I’ll have to test the motor running with the key on in the coming days... I do wonder about contamination, during multiple swaps of the accumulator and switch, I’m getting tiny dirt particles in the reservoir. I clean them out each time the system is pumped down but I’m curious if the hose that runs from the motor to brake cylinder is bad or something inside the motor itself is deteriorating. I’ve never experienced the motor running every time I push the brake pedal but if the light is out, then the system says it’s ok?!?

 

[Ttype6]

It’s hard to tell if the motor is getting hot. The roads are salty here in Ohio so I don’t drive either one of my Turbo Regals. I’m hoping it warms up and rains some to clean the roads off. The noise seems to be normal when the motor runs. I’ll have to test the motor running with the key on in the coming days... I do wonder about contamination, during multiple swaps of the accumulator and switch, I’m getting tiny dirt particles in the reservoir. I clean them out each time the system is pumped down but I’m curious if the hose that runs from the motor to brake cylinder is bad or something inside the motor itself is deteriorating. I’ve never experienced the motor running every time I push the brake pedal but if the light is out, then the system says it’s ok?!?

It is within the normal operating parameters. If I install an original/smaller accumulator,my motor runs with every depression of the brake pedal. When I install the newest/biggest accumulator,it turn on after 2 depressions. The acceptable range is 1-3 depressions. There could also be slight differences between the different switches as far as turn on and off pressures. The accumulator that you currently use could also be partially discharged. You can test for a leak buy turning the ignition switch to the run position to see if the motor starts on its own without depressing the brake pedal. If there is a leak,you should be able to watch the fluid rise in the passenger side reservoir.

 

[captndave737]

It is within the normal operating parameters. If I install an original/smaller accumulator,my motor runs with every depression of the brake pedal. When I install the newest/biggest accumulator,it turn on after 2 depressions. The acceptable range is 1-3 depressions. There could also be slight differences between the different switches as far as turn on and off pressures. The accumulator that you currently use could also be partially discharged. You can test for a leak buy turning the ignition switch to the run position to see if the motor starts on its own without depressing the brake pedal. If there is a leak,you should be able to watch the fluid rise in the passenger side reservoir.

He's saying it runs every time he hits the brakes not after 2 or 3 applications.

 

[Ttype6]

He's saying it runs every time he hits the brakes not after 2 or 3 applications.

I know. I quoted him saying this in post # 10. It is functioning within normal parameters. I suspect that his accumulator is partially discharged. I would re-install the original accumulator to see if that makes a difference.