Powermaster brakes diagnostic information

robzombie

Well-Known Member
if you cut the key on th motor starts like it should
What part of the south are you from??

I'm not trying to pick on ya, but yankees don't say cut the power on or cut anything on.

Just asking because if there are any members in your area that own/know these cars, it would be of more help than any mechanic who has never seen one let alone worked on one,would be of more help to you.

The powermaster system wasn't very well known back in the day let alone today.

Anyways, what I'm trying to say is find someone who owns one of these cars in your area and you will save both money and frustration when things get diagnosed right the first time.

If you fill out your sig, someone near you might offer to help by actually looking at your car.

OH YEAH!, my favorite thing to cut is a good light!!

RZ
 
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robzombie

Well-Known Member
I just read the whole thread and from what you describe it sounds like you have a leak at the rubber hose fitting or in the hose itself.

First get that leak fixed and maybe you will stop popping the fuse.

I'm not confident that will solve the fuse issue though. It sounds like the motor windings are shorting out and the best fix is to get another powermaster unit installed that will come with everything new, switch/$100, accumulator/$200 and motor/with master cylinder. To buy all those parts individually would be over $600.

You can buy the whole unit complete for under $450.00 reman with warranty or used on the board here for about $200 or less, or your final out would be vacuum setup like you already stated, but you will need to get the brake pedal from a vacuum equipped car also as the powermaster pedal setup won't work.

Hope this helps you out.
 
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TurboDave

RIP DAVE
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May 24, 2001
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Dav here is a few pics some are blurry but I have my hand where and on wha is leaking.


OK, down there where your hand is, is the pump end of the high pressure hose. It can be replaced if you can find someone with some used powermaster parts laying around. It just unscrews from the pump assembly, but has to be disconnected at the other end of the hard line where it connects to the master cylinder on the drivers side because the whole hose assembly spins as you're unscrewing it from the pump. DO NOT try separating the rubber half from the hard line half. It takes some special tooling.
The way to do it without removing the motor/pump assemble is to...
1. Depressurize the system with 10 key off pedal pushes.
2. Completely empty the reservoir. Turky baster or vacuum pump, or whatever method works.
3. Disconnect high pressure hardline from driver's side of master cylinder.
4. Put something under pump to catch fluid spill and then disconnect/unscrew the end of hose (where your hand is) from the pump

Threads on either end of the high pressure hose are NOT a seal, but rather the tip of the pump connector and hard line tip on the other end.

You can replace the Powermaster with a vacuum system if it's more to your liking, or repair the line if you want to keep the PM for stock appearing purposes.
Since you're probably not big on drag racing and don't need the boost holding power of the PM, a vacuum system might be more to your liking.

If you do decide to go with a vacuum system, don't forget to get the vacuum system pedal also. They're different.
 

robzombie

Well-Known Member
OK, down there where your hand is, is the pump end of the high pressure hose. It can be replaced if you can find someone with some used powermaster parts laying around. It just unscrews from the pump assembly, but has to be disconnected at the other end of the hard line where it connects to the master cylinder on the drivers side because the whole hose assembly spins as you're unscrewing it from the pump. DO NOT try separating the rubber half from the hard line half. It takes some special tooling.
The way to do it without removing the motor/pump assemble is to...
1. Depressurize the system with 10 key off pedal pushes.
2. Completely empty the reservoir. Turky baster or vacuum pump, or whatever method works.
3. Disconnect high pressure hardline from driver's side of master cylinder.
4. Put something under pump to catch fluid spill and then disconnect/unscrew the end of hose (where your hand is) from the pump

Threads on either end of the high pressure hose are NOT a seal, but rather the tip of the pump connector and hard line tip on the other end.

You can replace the Powermaster with a vacuum system if it's more to your liking, or repair the line if you want to keep the PM for stock appearing purposes.
Since you're probably not big on drag racing and don't need the boost holding power of the PM, a vacuum system might be more to your liking.

If you do decide to go with a vacuum system, don't forget to get the vacuum system pedal also. They're different.

Now that there is some accurate instructions!!
 
Sep 28, 2013
57
2
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Shenandoah Virginia
Thanks so much you guys this really helps out alot.Just really confussed,I know it's been a problem for a few weeks and a little dangerous.I take my beauty to work and maybe a car show or two but haven't tried the racing thing yet.:) Why have it if ya can't drive it.I think the guy that had it before me just didn't drive it enough and stuff is a little worn out. Really low miles though 70,000.I think it will be ok though with the help of others opinions. Thanks you guys!
 

86GN-JT

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Nov 18, 2013
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Hello...just picked up an 86 with 15K from original owner. Power master wasnt working so I just had it rebuilt by Cardone (big $$), and then I changed the brake conversion (proportioning) valve as recommended by Cardone to brass one (from Highway stars). Filled master with fluid, followed directions from Cardone, but cant get a pedal, just goes to floor. Pump is working fine.... Anyone have any idea or information abut bleeding the brake system on these things? Is it same as usual; start from furthers wheel and work your way up? No sure what to do at this point.... any help or info would be greatly appreciated... thanks.
 
Sep 28, 2013
57
2
8
51
Shenandoah Virginia
Hello...just picked up an 86 with 15K from original owner. Power master wasnt working so I just had it rebuilt by Cardone (big $$), and then I changed the brake conversion (proportioning) valve as recommended by Cardone to brass one (from Highway stars). Filled master with fluid, followed directions from Cardone, but cant get a pedal, just goes to floor. Pump is working fine.... Anyone have any idea or information abut bleeding the brake system on these things? Is it same as usual; start from furthers wheel and work your way up? No sure what to do at this point.... any help or info would be greatly appreciated... thanks.
I converted mine to vaccum brakes this is the way to go .But you may want yours stock just a suggestion.
 
Jun 24, 2008
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86 GN i had the same issues. The first thing i had to do was bench bleed the master cylinder first. The next step was then starting at the furtherest wheel and work forward. It was good after that.

ImageUploadedByTurboBuick Mobile1385653698.645548.jpg


Theres a pic of bench bleeding MC setup. This may or maynot work for you, but i had to do it to fix some pedal travel issues.


Posted from the TurboBuick.Com mobile app
 
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chopped39

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Aug 30, 2004
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To bench bleed it properly the master has to be off the car.There will be air trapped at top of master if not. It has to be horizontal to get all air out. I use to flush my fluid sometimes twice a year and my master never gave me any problems until it went out at 40mph when someone through a u-turn in front of me. The system is to unpredictable. Gm should have converted these cars to vacuum . Why do you think they didnt use it on the 1989 turbo trans am. For a show car thats not driven a bunch I would stay with the power master. The biggest thing is converting the car to stainless lines and flex hoses. This will keep the copper out of the system and keep it a lot cleaner.
 

86GN-JT

New Member
Nov 18, 2013
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Thanks for the feedback. I did bench bleed the master while off the car in a vice. I think the fact that I changed the proportioning valve as well has added extra air in the system, hence no pedal at all. I will try bleeding them fully starting from the rear and see what I get. thanks...
 

Joe 1320

Torqueus Maximus
Feb 28, 2002
890
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Florida
Any chance the original poster can change the font color? Since. He new background color change, all of the original post is unreadable
 

GNguy198687

New Member
Jul 24, 2014
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Hi guys, Dan from Scranton Pa. New here, is this where and how I ask questions about the power master system? My question is, does any one sell a complete rebuild kid for this unit? Both the pump and master cylinder? I had my pump apart onece already and fabricated a seal spacer for the pressure end cap seal so I can use a readily available square quad "O" ring instead of the rectangular quad "O" ring that was original. That mod is fine and not my problem. I recently developed a leak from the motor and my guess is it is the seal between the motor and pump. So before I take it apart again, I'm wondering if anyone offers a seal, o ring, gasket, cup seal kit? Thank u
 

Turbo85

Member
Mar 8, 2006
254
3
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70
Calif
To properly bleed the brake system on a PM system do you have to de-pressurize the system first? Or just pump the brakes with the ignition on?
 
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