Last week I took my car our of the shed and noticed the powermaster did not start up. I followed the gnttype.org steps on diagnosing it. The switch had resistance between all the terminals. I then check the fuse and it was good. The motor terminals between b and d did not have resistance. I purchased a used motor, after installation the fuse now blows after startup. Does this mean my new motor is bad, or is there something else I should look for?
powermaster question
- Thread starter skidlid
- Start date
My fuse kept blowing. It was caused by the pressure switch. I replaced it and it's been good for almost 2 years now. Knock on wood!!
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BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
The switch is supposed to turn the motor on and turn the motor off based on pressure. If the switch does not shut the motor off when it's supposed to, the pump might continue running until the pressure became so high and loaded the motor so much that it blew the fuse. Never seen one do that, but it could potentially happen. If that were happening, I would expect to hear the pump working very hard pumping against very high pressure along with a lack of "click" from the switch when it's supposed to turn the pump off. Then "pop" goes the fuse.
BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
see attached. look for symptom "pump motor runs does not shut off in 20 sec"
If you intend to keep the powermaster, I recommend you try rebuilding it and get to know it. Kirban carries most of the parts needed. O-rings, switch, accumulator.
when parked for more than a day or so, de-pressurize the system by gently pumping the brake pedal with key off til the pedal gets hard. I think relieving the pressure is much easier on the seals and the parts compared to leaving it sitting for days or weeks on end with several hundred PSI pressure in it.
swap in clean fresh fluid in the reservoirs every spring. do not overfill the pump sump side.
If you intend to keep the powermaster, I recommend you try rebuilding it and get to know it. Kirban carries most of the parts needed. O-rings, switch, accumulator.
when parked for more than a day or so, de-pressurize the system by gently pumping the brake pedal with key off til the pedal gets hard. I think relieving the pressure is much easier on the seals and the parts compared to leaving it sitting for days or weeks on end with several hundred PSI pressure in it.
swap in clean fresh fluid in the reservoirs every spring. do not overfill the pump sump side.
BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
I keep a few switches in my stash, but 8 or 10 years ago I started de-pressurizing when I parked the cars and since then I've never had another pressure switch wear out on me. I also listen for the pump run and shut off when I key on, then start the engine after the pump is done.
