I have a power master system that was taken off one of my turbo buicks in the past. I dont know which part of it failed, I think just the accumulator, but it could be the power master. At the first signs of brake failure, we pulled it off and replaced it with vacuum brakes. It has the original switch and original all black accumulator still on it. When we pulled it off the car the brakes worked but it felt like a bad accumulator (have changed them in past), but I can't guarantee the power master will work or not need to be rebuilt. It is what it is. The brakes worked good when I first got the car. ha ha im sure thats what everyone says. Sorry to those of you who were interested in buying it before, I lost all my messages on here so I don't remember. Ill take the best offer for it... start the bidding at...50 plus shipping anyone?