Powermaster support thread!

[Keller]

Why did GM go from the hydroboost to the Powermaster in 1985?

Weight savings, perhaps. I would say to reduce parasitic losses, but the power steering is still there, and I doubt they used the brakes during normal HP/TQ tests or EPA fuel economy tests.

 

[wbrophy]

PM= Good Stuff

After 20 years my OEM unit started a slight leak at the rear of the master were the rod goes in. Sooo

I replaced it with a rebuild master cylinder with a brand new Kirbin top reservoir, a larger volume German made accumulator ball and a brand new motor; than I filled the complete system with DOT 3/4 synthetic brake fluid, added the brass proportioning valve along with all Stainless Steel brake lines through out with braided SS flex lines front and rear along with the Dual Caliper S-10 front brakes and new S-10 rear cylinders.

The complete PowerMaster system looks brand new or even better from stem to stern and with those S-10 dual caliper front disk brakes it stops like never before and even after the car sit's for a month I still have "POWER" brakes without putting the key in the ignition.

The PM system has an electric motor for the pump which produces more pressure than a vacuum system for better stopping power and does not run directly off the engine like the Hydro-boost. Hell; your engine can stall all day long but as long as you have juice you have "POWER BRAKES".

PS: The synthetic DOT 3/4 Valvoline brake fluid that I used exceeds DOT 3/4 specs. but will mix with all DOT 3 and 4 brake fluids.

Edit: Car stops with no problems "what so ever" at 130+ mph on a short shut down area. Forgot to mention that I have the 4 larger brake shoes in the back aluminum drums too along with a line lock. PIC OF CAR AT MIR BELOW.

 

["Turbo-T"]

It's still a pump with pistons and rubber seals. What the heck you going to do when it fails?

Use your e-brake, and hope it works (which any street car should be mandatory to have a working e-brake)

Yes I am aware a master cylinder is nothing but a pump and seals, that is irrelevant to the topic.

The topic isn't about the master cylinder itself. It's about the power brake assistant. Be it vacuum, non power assist (manual), powermaster or hydroboost.

If the master cylinder itself failed, it wouldn't make a bit of difference if you were running vacuum brakes, or manual brakes or powermaster brakes or hydroboost brakes. You'd not have brakes. At all. period.

I would imagine had the PM been available a few more years the geniuses would have figured out how to work the bugs out of them, so that they were less prone to failure.

 

[GNX243]

What to do if master cylinder failed

Use your e-brake, and hope it works (which any street car should be mandatory to have a working e-brake)

If the master cylinder itself failed, it wouldn't make a bit of difference if you were running vacuum brakes, or manual brakes or powermaster brakes or hydroboost brakes. You'd not have brakes. At all. period..

If you want to know what to do if the entire system failed, go to http://www.turbobuick.com/forums/ge...d-you-do-brake-failure-downshift-reverse.html
I've had this bookmarked for some time but haven't tried it out.

 

[Alky V6]

If you're in a braking emergency and you turn off the engine, the pump in the transmission will no longer be turning, the line pressure in the transmission will go to zero, and without line pressure you will have no gears. You can shift all you want. You will only have neutral in all positions, except park.

 

["Turbo-T"]

In drivers ed they taught us to downshift a little at a time, use the engine to help slow the car down.