Powermaster cycling every 10 seconds

Hey guys, the powermaster in my turbo t cycles every 10 seconds it seems like. No brake light, and it stops great... I can hear a small hiss under the dash while the car is on, and goes away with a touch of the pedal. Also, if I turn the car off I can hear the hiss slowly go away, which I assume is it depresurizing. Is there some sort of vacuum line that may be faulty?

Thanks
 

turbo nasty

Turbo Dojo / MNTR
Key off. Press and release brake pedal 10 or so times until it gets hard.....Make note of fluid level in engine side brake reservoir...turn key to on position with engine off...powermaster pump should turn on and pull the inboard level down to about 3/16" in 10ish seconds and shut off....level should stay there. If it starts to slowly rise back up then the check vale (as mentioned) isnt sealing and when this happens typically you can take valve out and wet sand it back flat with 800 or 1k grit.
 

BEATAV8

The Engine Whisperer
Needs a new seal kit. Kirbans sells the kit.

A new switch and a new style accumulator (if you have an original still) also recommended.
 

KC87

Well-Known Member
Key off. Press and release brake pedal 10 or so times until it gets hard.....Make note of fluid level in engine side brake reservoir...turn key to on position with engine off...powermaster pump should turn on and pull the inboard level down to about 3/16" in 10ish seconds and shut off....level should stay there. If it starts to slowly rise back up then the check vale (as mentioned) isnt sealing and when this happens typically you can take valve out and wet sand it back flat with 800 or 1k grit.
Maybe he'll be lucky and just a speck of dirt, especially if the fluid hasn't been changed often enough.
 
I will check it out tomorrow. The car takes 7 seconds for it to stop pumping with the key off, but never watched to see if fluid level starts to rise. The car sat for at least 8 years before I bought it november of last year and the brake system was gone through with hoses/cylinders and completely flushed as it was in dire need
 
Tore into it today and this is what I found

Polished it up with some 1000 grit cleaned it and slapped it back together. It quit cycling all the time and all is good now! Thank you for the advice fellas
I bought the car in November and did tons of reading before I approached anything, turbo Buick specific and this site is extremely helpful
 

Attachments

  • 15620283885350.jpg
    15620283885350.jpg
    162.8 KB · Views: 65

Darkstar72

Active Member
Tore into it today and this is what I found

Polished it up with some 1000 grit cleaned it and slapped it back together. It quit cycling all the time and all is good now! Thank you for the advice fellas
I bought the car in November and did tons of reading before I approached anything, turbo Buick specific and this site is extremely helpful

Where is this check valve? Did you have to remove the Powermaster unit from the car to get it out?

I have a similar issue with the motor cycling and my fluid will flow back up into the master. Some days it is worse than others. Lately it has been OK.
 

Darkstar72

Active Member
its in line with the hardline with the big fitting underneath the accumulator valve on the drivers side of the powermaster

any chance you could show the location in a picture? What I am understanding then is that it is in line from the hard brake line going into the master then? The front line or the rear line?
 
any chance you could show the location in a picture? What I am understanding then is that it is in line from the hard brake line going into the master then? The front line or the rear line?
not the front or rear lines, its the line directly below the accumulator ( big black ball) on drivers side of powermaster
 

Darkstar72

Active Member
not the front or rear lines, its the line directly below the accumulator ( big black ball) on drivers side of powermaster


Got it. OK. I will take a look tonight when I get home. Thanks.

Did you end up replacing the o ring as well before you reinstalled yours?
 
Top