Why is my powermaster running all the time?

VeesGN

Member
Joined
Jul 2, 2001
My brakes have worked fine until a couple of days ago. The brake light on the dash came on a couple of times, so I looked at it a little closer and noticed the powermaster motor is running all the time. I pulled the plug on top by the accumulator and the motor quit running. I don't want to burn up the motor, so I won't drive it until I figure this out. Any ideas?
 
I looked at a powermonster diagnosis article in the tech section of www.gnttype.org awhile back when I had the same problem. Of course the obvious is does it have enough fluid, about half full when the car is off I believe. Mine still runs more than it should at startup, but is still hanging in there. Good Luck
 
This is usually one of two issues. Either the accumulator ball is bad or the pressure switch is bad. Usually the ball is what goes. If you know of someone try their ball. It is easy to remove. depress pedal at least 10 times. remove ball install new one. Turn ignition on. It will take a bit to pump up but afterwrds test by stepping on the brake. You can usually go one to two times before the the pump will kick on. Hope this helps.
 
OK--I read a gazillion posts on the PM vs Vacuum debate and decided to dump the PM for now. I went to the junkyard yesterday afternoon and bought a booster,m/c and pedal and installed it last night. Hopefully I'll bleed the brakes and have it back on the road tonight. If it works good, then I'll be happy. If not, I'll try to repair the PM and re-install it later.
 
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