Help!!30 Amp Pwrmstr Fuse keeps blowing

[KevinG]

My Gn has only 11000 miles and probably all original brake parts. The pressure switch is the upgraded gray not black. The car ran and stopped fine( for a buick anyway!) then the brake light flashed on for less than a second each time the pedal was depressed relatively hard. I had a shop look at it and they said it was fine and a momentary flash is OK. I returning from the track one night and lost all power assist and the brake light came on and stayed on. I nursed it home and got out my GM diagnostic manuals and first thing was to check the 30Amp fuse. It was blown. I replaced the accumulator anyway and replaced the fuse but after the booster pressurizes the system the brake light will go out and all is well until I put the pedal all the way to the floor. It will blow the fuse. I have tried four fuses and blew them all so there must be an underlying problem that is way beyond my limited powermaster knowledge. Help

 

[REDS HOT AIR]

unplug the delay relay
its the bigger of the 3 relays on the drivers fender

it allows the fan to run when the car is not running
unplugging it wont affect normal operation oof the fan

the powermaster runs off the same power wire the delay relay does and them relays are know to go bad and it may be shorted


its worth a try atleast

 

[KevinG]

30 Amp Fuse

Thanks, I will give it a shot today, hope for the best

 

[Chuck Leeper]

PM??

Most likely the motor and/or the pump is toast.. If the Sw and the accum is good to go, then the power consumption by the motor is blowing the fuse.

 

[KevinG]

30 amp fuse blowing

Well, I tried disconnecting the hi-lo relay and doing so only increased the time it takes to blow the fuse. I have pretty much resigned myself to the fact that I have to replace the piece of @#$% powermaster, but is there a test to make sure that is the problem. Also, where to get a powermaster. Are the rebuilt units as reliable as a GM factory unit. Would a Buick dealer even have a technician trained to do this. Basically, I can live with cost to replace the unit but I want to make sure it is done correctly. Buick powermaster shop in Metro detroit? Thanks

 

[tpabayflyer]

Check out my thread about the completing the vacuum brake conversion...I had the exact same symptoms as you a few weeks back and I have great brakes now!!! get rid of the powermaster as it is at least 15 years old and it's continued reliable operation is very questionable.... I replaced my M/C in mine about 10 years ago and was on my 3rd accumulator ball so these damn things are nothing but trouble... I figured the cause of my failure was the electric motor as it was getting old and going bad.. it would generate lots of heat when running and would get very hot to the touch. It was not running continuously but would just get very hot very quick and pop the fuse regularly.. after popping 5 40 ampers, I bit the bullet and went to the junkyard and ripped a vacuum setup from an 84 regal.. works like a champ!!!!! TBF

 

[EFFNQWKWE4]

I had the exact same problem with my WE4. I was blowing 30a fuses like they were going out of style. I had board members tell me that the motor was probably toast and I too, thought that replacing the PM system was the only way out, but here's what I did. There are 2 plugs on the actual unit itself. I unplugged both and found a buttload of corrosion and gunk. I cleaned out both plugs, and did the same with the switch. After that, I popped one more fuse. When that fuse went, I disconnected both plugs again, cleaned out what was left, and haven't had a problem since. That was 6 months ago. Did I just get lucky? Maybe, But I battled the 30amp fuse thing for a month while trying to figure out what to do with my powermonster. I was replacing fuses 2 or 3 times a day in my car. HTH

 

[jj86gn]

Same thing kept happening with my 86GN. Was going to convert to vacuum but decided to keep it original and went with a rebuilt from Auto Zone. Believe it or not for $260.00 I got a totally rebuilt system, new accumulator, new pressure switch, rebuilt MC.

Don't know how they do it but it was well worth it. And they offer a lifetime warranty. Can't beat it! Might be the way to go. Good Luck.