Tell tale signs that a PowerMaster is about to fail?

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pkschul

Member
Joined
Jul 23, 2002
Hey all.
I just got my car up and running last year after sitting in the garage for 13 years.
While driving around I've been noticing that the brake pedal has a strange vibration while stopped at red lights. It feels mechanical and it's choppy feeling. Not really sure how else to describe it. Is this something I should worry about or is that normal? I'm very tempted to switch over to a vacuum brake system. I don't want to have the kids in the car when/if it fails.
 
Sounds like my previous powermaster, it happens every other, or every third, braking? I think it's the electric motor pressurizing the system. Eventually it turned on and never shut off - that's a sure way to burn up the motor if run too long. You should not be feeling it through the brake pedal.
 
pkschul said:
Hey all.
I just got my car up and running last year after sitting in the garage for 13 years.
While driving around I've been noticing that the brake pedal has a strange vibration while stopped at red lights. It feels mechanical and it's choppy feeling. Not really sure how else to describe it. Is this something I should worry about or is that normal? I'm very tempted to switch over to a vacuum brake system. I don't want to have the kids in the car when/if it fails.
Click to expand...

The surest indicator that your Powermaster is about to fail is that it hasn't failed yet.

They aren't safe. Unless your car is a concourse show car you drag around on a trailer, get rid of it.
 
I was looking at the Kirban's vacuum kit. $400 seems a little steep but I'll do it for peace of mind. Is there a less expensive route?
 
A bad pressure switch can cause the motor to turn on/off quickly, like a faulty connection. This will cause a vibration sensation in the pedal. This will quickly kill the motor. If you're in Florida, bring it over and I can diagnose it.
 
toomanymodz said:
A bad pressure switch can cause the motor to turn on/off quickly, like a faulty connection. This will cause a vibration sensation in the pedal. This will quickly kill the motor. If you're in Florida, bring it over and I can diagnose it.
Click to expand...

Thanks for the offer but I'm in Virginia.
 
Turbo6inKY said:
The surest indicator that your Powermaster is about to fail is that it hasn't failed yet.

They aren't safe. Unless your car is a concourse show car you drag around on a trailer, get rid of it.
Click to expand...
Agreed. Getting rid of that pos was my first mod. vacuum brakes work flawlessly. A booster is $80 and the master is $28 at parts store. All you need to find is a pedal, and some tubing.
 
I met a guy over the weekend who just drilled a new hole through the firewall to accommodate the power master pedal. I'm not sure if I want to go that route. Should I look for any G-body pedal from a car with vacuum brakes?
 
I'm not finding booster an master cylinder for that cheap. Where do you guys buy your parts? NAPA has the booster/cylinder combo for $143 plus $17 core... no core so $160.
Advance has it at $137 plus $25 core charge.
 
The powermaster (and manual) pedals have the clevis high up on the pedal and require an angle bracket on the firewall to keep the pushrod in line with the master cylinder. Vacuum pedals have a lower clevis, so to keep the pushrod inline, just remove the bracket. This thread has some pictures showing the different pedals and you can see the angle bracket between the firewall and mc as well: http://www.turbobuick.com/threads/manual-brakes-brake-pad-selection.419704/page-2

Drilling holes in the firewall... :rolleyes:
 
Advance auto. Use code trt30. eBay is a little cheaper. I used the kirban vacuum block but some have teed off the pcv valve line.
 
- Spend the $160 at the auto parts store
- Buy the billet vacuum block from Kirban
- Go to the junkyard and remove a vacuum pedal from any G Body, or browse the "for sale" section on this forum
- Buy the incidentals: brake fluid, 3/8" rubber / thick wall silicone hose ( 2ft. )
- Remove Driver side seat, and get to work
- Bleed the brakes, starting from the wheel furthest from the master cylinder, and work your way to the closest
- Enjoy peace of mindf
 
There's a pedal on eBay for 69 obo. Email intercooled88s. He might have one. His email address is in for sale section. There's a write up on gnttype website on procedure.
 
Pkschul.. If I was you I PM Sydwyndr Clint at RCG ... Richard and John Norton have written a book on just the Powermaster Brake
system, and I'm pretty sure it addresses that issue you having. Good Luck..
 
Thanks all. I'll be doing the swap. I'll look in to that pedal on ebay. I already posted a request for a pedal to an online junkyard group.
 
Since I am not a good scrounger and my time is often limited, I just got the complete kit from Kirban plus the brake pedal. Saved a lot of time. I also chose to upgrade the old brake lines from the wheel cylinders to the tees. It was a pretty straightforward swap. No worries about braking anymore. Yes , maybe a little more $, but for me it was well worth it.
 
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