Bleeding a Powermaster for 87GN

J

Jeff Moore

Member
Joined
Apr 26, 2007
[Does someone out there have a procedure to bleed a Powermaster]

I hope this is the only problem ..I have!

Anyway this week ..I just installed a used PM ..(seller says it was good)

..I have brakes..However the Press Sw keeps klicking on-off..(I did change

Sws..but still klicks) also the PM motor runs longer than it should..

The brake pedal ..initially is good > however ...if you hold the pedal

down (long enough) it will go to the floor..

there is no fluid leaks..

Any Ideas.. not bleed completely ...? thanks!
 
Sounds like the master cylinder needs a rebuild. It has an internal leak. If the pressure switch keeps cycling and the motor ran for a short time I would say it's the accumulator. With the motor running for a long time and your pedal going to the floor, I would say you have an internal leak. Time to rebuild.
 
+2
Pedal sinking to floor is a classic sign of a dying cylinder. I hope you didn't pay for that used unit. If you did, get your money back.

If I may offer a word of advice, NEVER place used brake components on any vehicle. If you are going through the trouble to replace any portion of the PowerMaster, it better be either NEW or at least FRESHLY REBUILT.

Your clicking is the switch turning the motor on and off at the set pressure levels. As your internal leak is allowing the fluid to bypass the seals, the switch senses the low pressure and turns on the pump. It runs to pump up and the switch turns it off. That motor will soon be toast if you allow this to continue.

P.S. I have to tweak the procedure...and going to get pics. Hope to do this soon. Very busy right now...on lunch break. If you have a specific question, feel free to ask.
 
Thanks for the info..I will start rebuild...of the MC...where is best place to get a kit..? and yes I did pay for it! However if the Accum is good!....the deal wasn't so bad.. I do agree with your advice ..paying the price ..and repairing the other guys problem..isn't any fun... Work with me! ...
 
PM Brakes

How good can these brakes stop? I put in a new Acc ball to stop the hard pedal issue, however; the car really doesn't stop all that well. I can push the pedal to the floor and eventually it stops. I certainly can not get it to come to a screaching halt. I know the cars are now 20+ years old, but how good did they stop new? Any input would be great, didn't mean to hiJack the thread, there just seems to be a lot of knowledge in it.

Thanks!
 
PJ,
My Powermaster will throw you through the windshield.
And my system is completely stock...even down to the original proportioning valve. I did replace the calipers and rear cylinders, but they were AutoZoo cheapos. Only problem I run into is brake fade due to undersized front rotors. So I just don't drive fast until I can upgrade.

A 20yr old neglected braking system will never work as good as a fresh system, regardless of style or design. Powermasters don't deal well with neglect. They have to be maintained. If your pedal is going to the floor, either your cylinder is gone, or you have air somewhere. Old fluid won't help either. You have to replace it once a year or two.


Jeff,

Good luck on finding a kit. Last place I found them was Welcome to Karps Brake Service And they were proud of them. I lucked out and had to rebuild before the kits were discontinued a couple of years ago. You may could find a board member who is willing to part with one.
 
Thanks for the reply. I bleed and replaced the fluid this weekend, to no avail. I see a person on ebay whose selling new cylinders for around $140. There are also whole PM systems on there for $450, OUCH!~ Could I start with the rebuild cylinder and go from there? I have a newer ball, worst case is I would still have to replaced the motor and the switch? Any input would be great.

Thanks!
 
IF you get the right cylinder, $140 isn't too bad being NEW.
IF the motor is going, it's pushing $200.
IF you know your acc is good, you can save $200.

In round figures, $450 for a complete, all brand new (partially rebuilt) Powermaster assembly that you bolt in and comes with a warranty....???? Do you see what I am getting at? You would still have a good acc ball for a spare. You can start taking care of it right out of the box.

Rebuild kits are hard to find for a good price. From what I have researched, Kirbans has the best deal right now. $420 with a warranty, and they give you $75 core for your old P/M.

The powermaster is good, it is just unfortunately expensive. Rare breed. Just remember that air is NOT your friend when it comes to brakes. Proper bench bleeding is REQUIRED for the powermaster. Cycling the acc to get the air out is a necessity.
 
Hey ..I found a kit (listed under turbo 3.8) $20, @ Autozone..will pick up 5/2...@ that time I will know for sure if it is the right one.. I will be pulling PM out today.. Will keep you posted...>Also thanks for continued guidance...
 
Say What??

Surely you jest??
Do you have a part number?
I have to go and find this out for myself.
Did you find it on the internet?

Please clue me in!!!
 
Welllllllll Autozone finally got the Kit in...and guess what!...It's not the right one..they misguided me / waisted my time!..... So > back to the drawing board...I tore the master cylinder down and found that one of the 3 (plunger) large "O" ring seals was broken.. The rest of the seals look pretty good..

Now.. next humble question...is there a kit out there? or any large "O" ring seals available? for the PM....

Sorry> if I raised anyones hopes of getting a cheap kit over the counter..
 
End Of Powermaster Story (87 GN)

Finally... the soft pedal to the floor was solved with a rebuild kit from Karps ($85, 909-987-0800) ...Then after this (cylinder) repair... another problem appeared; the switch and brake light kept coming on and off...and motor seemed to run more than normal....

So.. I checked accum for charge..it was... too low .., I replaced ...it and now have perfect brakes.. Thanks for help.!

Last note; I ended up investing $290 and a whole lot of labor...from a PM purchased off Ebay.....If you don't have the time / special tools / extra pair of hands / patience ..required for the job..I would suggest a rebuilt unit..for ($385-450)...
 
WOW.............no PM bashers. Must be a new and improved generation of GN/TR folks! Nice thread.

Hank
 
How much did you pay for the accumulator and where did you get it? Also, how was the PM rebuild if you have real good mechanical ability?
 
You can buy accums @ Kirbans and seals @ Karps...The PM rebuild was very time consuming and needed some special tools like; pliers, clamps, etc.. NOTE; if you have rebuilt a master cylinder before..then you can probably do it.. HOWEVER..if you know the accum and seals are both bad..(especially PMs with 65K miles plus) then I would advise purchasing a rebuilt unit...
 
brake problem s

i have a 87 gn thats been resting for 13 years when i say resting i mean fresh motor that hasnt been crunk . any ways the powermaster looks brand new but did not run so i took it apart eveything seems to be in working order but we got it to spin but it still seems week and has hard petel had dosnt really stop , o yea the power swich was stuck but we got it unstuck could it still be weak. what about air in the lines or the accumalator be bad cause the brakes stay hard all the time and wont hardly stop:mad:
 
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