The PowerMaster Bleeding Procedure

[gordyzx9r]

Replacing my Powermaster this weekend with a rebuilt one. This is the fluid that came out...I'm a little surprised seeing as how I had all new SS lines, aluminum drums, S10 upgraded rear brakes, and a complete SSBC system up front; and it was all put in around NOV and I haven't driven the car more than a few miles since then.

Look at the gunk in the bottom of that:

Getting the pushrod off the brake lever was allot easier when the plastic retaining ring broke hpbbt;

I was surprised how easy it is to take the whole thing out.

Bled the master cylinder...bleeding the rest of the system and putting the Russel speed bleeders on the rear. Taking a break right now.

 

[noneed4nos]

help!!

Ok so i have been reading this forum for about an hour since this is so much info here but i can really tell you are very good at these brakes systems, so i could use your help. OK so i bought my GN a couple of months ago and my acc. bowl was pissing out so i changed that out and my brakes worked good for about a week, then it sat for a little while and when i went to move it, the brake pedal was hard and very hard to stop as well without even touching the gas pedal just rolling. So this past weekend i just chaged all the drums, shoes, pads, rotors and brake lines to braided ones, i also had my buddy test my p.m pump to makes sure it was still working. There was/is no brake light on but not sure if the gauges are working correct.
So my two questions now are:
1) What else can be the problem if my pedal is still hard after i bleed my lines tomorrow? I am going to empy the resovoir out completely and put new fluid in and let it cycle but what can fix this problem?
and two
2)How can i bleed the rears, The fronts have the bolt that i can just take off let it bleed out and put it back in, but the rears have a flat,rould head that i dont know what/how to take it off. And if i do finallly get it out to bleed the rear drums, am i going to have to buy a new cylinder for just for that bolt? So basically how i correctly bleed the rear drums?
THanks for all the info you have posted and if you or anyone else can help me with these problems i would greatly appreciate it. THanks

 

[Swt_86]

Nasty

Wow - Zeus will probably chime in here in a short time but by the looks of your brake fluid in the system... I would look for a rebuilt PM and change out or rebuild your wheel cylinders and calipers. A hard pedle really has not much to do with the condition of shoes, wheel cylinders brake lines or calipers - it is usually the sign of a failed or failing PM unit and/or switch. I would recommend the rebuild of the cylinders and calipers only due to the way the brake fluid that came out looks - lots of junk in there which could cause accelerated wear.

 

[noneed4nos]

Yes i know the hard pedal and the bleeding of the rears drums are totally seperate problems, i just need both answers haha
I need to know how to either get off the bolt/head on the rear drum cylinder, to bleed it or do i change the cylinder out? After i figure that out, i can clean the system out and see if my pedal is any better, That is after i bleed the brakes of course, and if they are still hard, then i guess my only next option if their is nothing else to fix it easy, i will have to get a rebuilt one

 

[Pronto]

The rear brake cylinder has a boss around the bleed screw that makes bleeding a little difficult. You can get a new set of wheel cylinder for something like $10 a piece. They are held on with a funky spring. There is a tool to get that off. It's cheap too.
Did you do the test proceedures for the hard pedal? Doing the brakes is great but if the pedal is hard because the pressure switch (one possibility) is not working, doing the brakes won't help.

 

[noneed4nos]

Yea my buddy just told me how to get it off, its an odd shaped circle head to bleed the rear drums, but if i have too i will just changed the cylinders. And i had to change the brakes anyway, they were medal to medal but i clean my lines out and my pump and have a new acc. bowl so im going to try cleaning it all out bleeding the lines and putting fresh **** in and seeing if the pedal is still hard.

 

[zeus87gn]

Hey there,
I'm running late as usual, it's the story of my life now.
I'm ready for this moving business to be over....anyway, on with the issues.
I'm guessing you have done some work on your system, but I will still answer your questions because I don't know if you got them going again.

There was/is no brake light on but not sure if the gauges are working correct.

That being said, don't count on it. Mine doesn't work either so you are going to have to do the full diagnostics routine. You can look into the wiring of the brake light circuit easy enough. If it comes on when you press the parking brake, the light is working. It's either the switch malfunctioning or your wiring isn't connected.

So my two questions now are:
1) What else can be the problem if my pedal is still hard after i bleed my lines tomorrow? I am going to empy the resovoir out completely and put new fluid in and let it cycle but what can fix this problem?

If you have done all you can think of, you need to check for internal leaks. Read the Diagnostics Procedure and pay attention to the 2 minute test for self cycle.

and two
2)How can i bleed the rears, The fronts have the bolt that i can just take off let it bleed out and put it back in, but the rears have a flat,rould head that i dont know what/how to take it off. And if i do finallly get it out to bleed the rear drums, am i going to have to buy a new cylinder for just for that bolt? So basically how i correctly bleed the rear drums?
THanks for all the info you have posted and if you or anyone else can help me with these problems i would greatly appreciate it. THanks

Recessed in the middle of that flat round head is the bleeder screw.
You bleed them like ay other slave cylinder.
But I would imagine you figured that out already.

Let me know.....
Z

 

[captndave737]

GN Brakes suck!

I've hated my brakes for 23 years. When the original powermaster died I replaced it with a vacuum system thinking it would be better. It was cheaper but didn't stop the car any better.

I then went to Hydroboost. Awesome! I could actually lock the brakes if I wanted to but the whine drove me crazy. Yes it was bled properly. Replaced the PS pump and no relief.

After reading this thread I decided to put in a rebuilt PM from Kirban's figuring things had just never been set up right even when I bought it new.

Installed, bled fluid changed etc. and it sucks:

First-there's about 3" of pedal travel before anything happens.

Second- it's almost impossible to lock the brakes. In fact I can't if I apply the brakes gradually. I can lock the backs if I jump on the the brakes and not lock the fronts at all. Just like when I picked it up from the dealer.

Third-It holds pressure great. I can have it charged at night and in the morning it hasn't bled down enough for the motor to run when I turn it on. I've left it with the key on for over an hour and it's never bled down until I use the brakes.

It seems to me that it takes too much fluid and travel to overcome the limits of the combination valve and there isn't enough travel left for the fronts to be as effective as they should be. I have adjusted the backs so the shoes are slightly dragging and that hasn't helped. I think the Master cylinder is poorly sized for the car, both vacuum and powermaster.

All the other cars I've had during this time all stop without me getting wide eyed! 2 BMW's a 2 Toyotas and a VW!! Maybee I have to go back to Hyhdroboost and wear earplugs.

 

[Vancopbs]

If the pump and hydroboost are of good quality and installed correctly there should be zero whining. It's not something to deal with, but something that needs fixing.

 

[zeus87gn]

I've hated my brakes for 23 years. When the original powermaster died I replaced it with a vacuum system thinking it would be better. It was cheaper but didn't stop the car any better.

I then went to Hydroboost. Awesome! I could actually lock the brakes if I wanted to but the whine drove me crazy. Yes it was bled properly. Replaced the PS pump and no relief.

After reading this thread I decided to put in a rebuilt PM from Kirban's figuring things had just never been set up right even when I bought it new.

Installed, bled fluid changed etc. and it sucks:

First-there's about 3" of pedal travel before anything happens.

That's normal. Mine does the same thing.

Second- it's almost impossible to lock the brakes. In fact I can't if I apply the brakes gradually. I can lock the backs if I jump on the the brakes and not lock the fronts at all. Just like when I picked it up from the dealer.

If you ever meet a GM engineer, punch him for me.
They put too small of rotors on the front wheels to accomodate the stupid steel rims they designed. Go for some 11 or 12" rotors and you won't believe it.

Third-It holds pressure great. I can have it charged at night and in the morning it hasn't bled down enough for the motor to run when I turn it on. I've left it with the key on for over an hour and it's never bled down until I use the brakes.

It seems to me that it takes too much fluid and travel to overcome the limits of the combination valve and there isn't enough travel left for the fronts to be as effective as they should be. I have adjusted the backs so the shoes are slightly dragging and that hasn't helped. I think the Master cylinder is poorly sized for the car, both vacuum and powermaster.

What are the condition of the pads on the front and did you bleed them until you were blue in the face? Your calipers could be on thier way out.

All the other cars I've had during this time all stop without me getting wide eyed! 2 BMW's a 2 Toyotas and a VW!! Maybee I have to go back to Hyhdroboost and wear earplugs.

BMW's are in a different class. GM can't keep up.
Toyotas - well, lets not go there.
VW's are a good machine.

 

[zeus87gn]

If the pump and hydroboost are of good quality and installed correctly there should be zero whining. It's not something to deal with, but something that needs fixing.

Agreed. Somthing was wrong.

 

[captndave737]

Everything in the system was new when I put it in. Now I've been through 2 hydroboost units and 3 PS pumps trying to fix the whine. When the PS pump was new it was slightly better. There are NO air bubbles, It's been bled to death, I drive it several times a week and the conversion was done 2 years ago.

It stops on a dime with this setup and I love it except for the whine. Maybee I'm particularly sensitive to this sound since I'm on the highway so much. There's no change in sound while turning or braking, it's constant and annoying.

 

[t-topflyer]

Please make this a sticky

Sticky x 3

 

[Jerryl]

TTT

 

[zeus87gn]

Always interesting to read back on some of these issues.
Thanks for the props!

 

[TurboBuRick]

Great thread. Consider it stuck.

 

[monkeyy337]

I have a power master on my 84 Regal (not GN) race car. The brake light comes on when you first push on the brake pedal but will go out if you pump the pedal a few times, the car stops great whether the light is on or off. The light has always come on when I engage the line lock and do a burn out, but used to go off when I pumped the pedal a few times after the burn out. Last week I changed out the complete front brake spindles, rotors, and calibers for a Wilwood set up but the light still comes on. The car had been setting for about a year since last raced (brakes used) if that matters. Thanks for any help.

 

[TurboDave]

If it is truely a Powermaster (on an 84? are you sure it's not a hydroboost?), then the most likely culprit is the accumulator ball.

 

[monkeyy337]

It is a power master, its a Regal not a GN, it of course didn't come on the car, I added it so I could run a motor that didn't produce much vaccum but still have good brakes.

 

[zeus87gn]

If it is truely a Powermaster (on an 84? are you sure it's not a hydroboost?), then the most likely culprit is the accumulator ball.

Agreed.