New Powermaster Problems

[bob86gn]

I got a remanufactured PowerMaster, installed it last weekend and all appeared to be ok on the ride home. Drove the car yesterday and after about a half and hour of stop and go driving the pedal started to go away. I would sit at a light and with constant pressure the pedal the car would start to creep.

The powermaster was bench bled on installation and then the wheels were all bled when the PM was installed. I put the car on jack stands today, gravity bled the entire system with 48oz of fluid and did a final bleed with a Mighty Vac. The pedal will still slowly go to the floor. I rebled the PM and get no air out at the fittings. I literally have been bleeding brakes since 8am (1PM now) and there is no change in the pedal.

Think I got a bad PM? Why would be run ok and then loose the pedal? I am stumped, frustrated and just about out of brake fluid.

 

[Steve Wood]

Sounds like the master cylinder died....so called remanufactured PMs may not be all that reman'ed. Take it back and get another one.

 

[bob86gn]

Steve that was my thought. I may try to swap in my buddies and see what happens.

 

[turboman38]

Check two things before you pull it off. I have one of these issues happening to my car right now and the other happened to me when I put my "rebuilt" power monster on.

Look at the proportioning valve for leaks which mine is doing right now. I found a recall bulliten on this that said the cast iron proportioning valve (on my car now) should be replaced with a GM brass unit.

Look at the rubber hose coming from the bottom of the master cylinder going to the pump. Mine on my "bran new rebuilt" unit was sliced making the pedal go to the floor every time I hit the brakes regardless of how much bleeding I did.

My advice and humble opinion: GO TO VACUUM!!!!!

 

[bob86gn]

Turboman, I replaced the proportioing valve with the brass unit when I did the powermaster, the hoses all appear to be dry. The only place that looks a little wet is the back seal between the reservoir and the cylinder. The reservior moves a lot.

 

[turboman38]

Sounds like the master cylinder has an internal leak. I'd go with Steve Wood's advice on getting another one.

 

[drew666]

Powermaster

Could be accumulator. Raise hood - turn ignition on without starting - listen for electric pump running with brake pedal pushed. Pump should run for about 10 seconds and turn off. If it runs longer or doesn't turn off after about 10 seconds, it could be a bad accumulator (the ball on the side of master cylinder). With a bad accumulator brakes will still work but not very good because they need the pressure from the accumulator to modulate. Part#18038507. Got mine from GM, but is made in Germany. Hope this helps. Drew

 

[Roger]

I got a lifetime warranty with my PM & so far, I haven't had to use the warranty. If I have problems as you describe, I'd be checking out the warranty ( the accumulator ball is included in the warranty).
I tried vacuum conversion & had so many problems with it, I went back to the PM. Pm with warranty was cheaper than the vacuum conversion.