Why did GM decide to use the powermaster setup on our cars, Was it originally better than the vacum boost or did they just want to try something different, I really dont understand how it is worse, or is it that it just gets worse the older it gets?
general brake question
- Thread starter Haynesie
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from a mechanical veiw it offered great braking power that didnt give a driver the hard pedal feel thatcould possibly come with low vac on a vacuum booster system (not looking to debate which is better) only problem is they installed them without evaluating their long term reliability, and Im sure they had plent of mechanics billing under warranty for their repairs , in 89 they apparently saw the error in their ways and went with conventional vac booster in the turbo TA (dont hear them having troubles and if they had drumsinstead of discs they probably hold lots of boost )
when the PM system works they work good and are capable of high line pressure but they are probably responsible for the demise of more turbo cars than time , elements theft or bad driving combined.
when the PM system works they work good and are capable of high line pressure but they are probably responsible for the demise of more turbo cars than time , elements theft or bad driving combined.
Red Regal T
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Nothing wrong with a powermaster except the price of replacement parts and some would cite reliability. 
If you can swallow throwing lots of money at the powermaster that you wouldn't have to with a vacuum brake system, that means your financially independent. 
If you can swallow throwing lots of money at the powermaster that you wouldn't have to with a vacuum brake system, that means your financially independent. Interestingly Enough
Ford uses its version, I think its called Hydraboost braking, on its Power Storke equipped trucks. It was used because of it being a turbocharged diesel. In Ford's case it was the only choice since diesel motors do not create vacuum, eliminating the possiblity of vacuum asisted brakes. However in turbo applications the myth is that vacuum brakes are BAD
Nevertheless, Ford's Hydraboost is problematic, leaks and is very expensive to repair/replace. My point, even newer technology remains unable to fix the problems with PowerMaster style braking systems.
Ford uses its version, I think its called Hydraboost braking, on its Power Storke equipped trucks. It was used because of it being a turbocharged diesel. In Ford's case it was the only choice since diesel motors do not create vacuum, eliminating the possiblity of vacuum asisted brakes. However in turbo applications the myth is that vacuum brakes are BAD
Nevertheless, Ford's Hydraboost is problematic, leaks and is very expensive to repair/replace. My point, even newer technology remains unable to fix the problems with PowerMaster style braking systems.
GM trucks have used Hydroboost for 20+ years
And they have proven to be quite reliable. I have replaced a couple of units, but only after 180K to 250K of hard (parking lot sweeper) service. 4 to 8 hours a night of driving around parking lots at about 3 MPH. I'd say that's pretty reliable.
And they have proven to be quite reliable. I have replaced a couple of units, but only after 180K to 250K of hard (parking lot sweeper) service. 4 to 8 hours a night of driving around parking lots at about 3 MPH. I'd say that's pretty reliable.
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Why a Powermaster in a GN?
There has been lots of opinions, comments and conjecture about the Powermaster being used on the turbo cars and why?
The only thing close to a factual accounting I have been able to obtain was from a GM engineer working on the T-R program.
Back in 1986-7 many of these cars were at the GM Desert Proving ground here in Mesa, AZ for evaluation and testing. I was fortunate enough to know a few engineers working on this project.
I asked this question also. The response was GM was developing the ABS systems for various model and wanted pilot program to field test the electro-hydraulic power assist system being readied. The limited, relatively small run of turbo cars [and a few station wagons] seemed to fit the bill.
The credibility of this "story" can be verified by later GM vehicles [the 1989 Cad for example] that used the ABS system that looks almost identical to our PM.
There has been lots of opinions, comments and conjecture about the Powermaster being used on the turbo cars and why?
The only thing close to a factual accounting I have been able to obtain was from a GM engineer working on the T-R program.
Back in 1986-7 many of these cars were at the GM Desert Proving ground here in Mesa, AZ for evaluation and testing. I was fortunate enough to know a few engineers working on this project.
I asked this question also. The response was GM was developing the ABS systems for various model and wanted pilot program to field test the electro-hydraulic power assist system being readied. The limited, relatively small run of turbo cars [and a few station wagons] seemed to fit the bill.
The credibility of this "story" can be verified by later GM vehicles [the 1989 Cad for example] that used the ABS system that looks almost identical to our PM.
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