Bleeding a Powermaster for 87GN

[Jeff Moore]

Need more info; WHAT happens when:

1)you initially turn the key on..> elec mtr noise, sw noise, brake pedal, etc?
2)you hit the brakes when driving> elec mtr noise, sw noise, brake pedal, etc?

 

[zeus87gn]

Jeff's questions are valid. This information will certainly help with the dianosis, but just right off I will bet your acc ball is gone. An acc that hasn't seen pressure in 13yrs most likely blew the diaphram on the first revolution of the motor. They have a short shelf life. They don't like to sit.

I will guess - the motor either just clicks on an off briefly (less than a second or so) and the pedal stays hard all the time.
Do I win?

My curiousity has gotten the better of me.
How did you unstick the pressure switch?

 

[WINDMILL]

powewrmaster

I've been helping ike on his gn. we took my pressure swith off my gn and it worked on his to make his motor run. hi pressure switch i hit it with a hammer a time or two and put it back on and it worked then. the motor dont seem to put enough air to make the brake feel right(still hard), and the motor run all the time. the motor was stuck at one time too. any help would be nice. thanks

 

[ike]

brakes

yes when i turn the key on the motor runs but dosnt stop . but i still think the motor is week just dosnt hum like monks does . thank s for the help:smile:

 

[Jeff Moore]

Sounds like you have two paths for your 13 year old PM (mileage unknown);

1) Start Replacing Parts>accum-$160, mtr/pump-$150,... note; if fluid is dark black your seals-$90 are going bad.., & finally your Labor-$xx..

2) Purchase a rebuilt unit> around $400 with guarantee and peace of mind..

 

[buzzman]

guys.....where to purchase? checked autozone, advanced, federated, kirban says back order due to lack of cores...even went to the local buick dealer....all no avail....need one......help!!!!

 

[GNRick]

Email Cardone and maybe they can help. Also check E-bay.

eBay Motors: 86-87 Buick Grand National Powermaster Brake Unit (item 260159218369 end time Sep-18-07 10:24:44 PDT)

 

[buzzman]

thanks, didn't think of contactiing cardone direct

 

[Jeff Moore]

Also, compare.. turn around time..from the rebuilders ..if you send them a core....

Patience! Brother!

 

[buzzman]

who are the rebuilders? i wouldn't mind sending for a rebuild. have zero experience with these although i am a longtime gn owner.....what is the take-off procedure. i also see a small amount of seepage under the switch and my reservoir doesn't seem to sealed well to the master...it kind of rocks back and forth.....see some wetness under rear attachment point....any advice much appreciated

 

[GNRick]

Just Kirban as far as I know.

 

[ike]

brakes

tbird is the man on the powermaster if he has any left

 

[buzzman]

t-bird???? help me out.....how can i contact etc. my car rarely comes out of the garage but it drives me nuts when it is just not right. thanks

 

[hvyresq]

PM Problem

Recently replaced the entire PM with one off E-bay. Installed the unit, Benched bleed it and still and a hard pedal with little brake and the light is always on. Turn the ign on and the unit runs for about 3 seconds then shuts off. Any idea??

 

[Jeff Moore]

Ok.. more info..
1) Does the pedal go to the floor with constant foot pressure?
2) When driving..(if brave enough), does the motor run a few sec.s
after you apply the brakes?

Let me know...??

 

[zeus87gn]

Recently replaced the entire PM with one off E-bay. Installed the unit, Benched bleed it and still and a hard pedal with little brake and the light is always on. Turn the ign on and the unit runs for about 3 seconds then shuts off. Any idea??

Is this a fresh rebuild or a used unit?
If it's used, you have installed a bad unit and you need to run diagnostics to find out where your problem is.

If it's fresh, have you bled the accumulator?
See link in my sig for proper bleeding on a fresh installation.
Bench bleeding takes care of the main cylinder portion of the P/M, but the high pressure side is a different story.

 

[2toneNV]

Jeff Moore, where is the best place to get a rebuilt PM? Also, I have replaced the Pres. Switch but I get the hard pedal feel with the brake light coming on, would you say rebuilding the Master Cylinder is a good idea? I just don't want to invest alot of money in trying to fix this one and still end up in the end having to buy a rebuilt unit.

 

[Jeff Moore]

Ok...I don't have much info to go on..but I'll try!!!

- Sounds like you might have an Accum problem.. 160-$200(Ref Kirban)
- If you think you need a total rebuild.. pending car has 70K+ miles and
has dark blackish fluid.>.suggesting master cylinder seals are bad..
then I would go with ..a rebuilt unit ..(Auto-Zone>$475) / (Kirban>$??)..

If you are thinking rebuild ..I would recommend not doing it yourself..I went this route ..and it cost me $390 not counting my labor..Plus I had to get very creative with special..tools.. However...(when working) the PM brakes are excellent........and would never go to a vacuum!!!

Hope this helps!!

 

[Jeff Moore]

Also try Advanced Auto !!..they show they have them on the Web..today..

 

[2toneNV]

I heard that the one from Kirban's which is a Cardone unit that it doesn't have the proper psi? That it is around 160psi when the original was 300-400psi. The fluid is not black, the motor doesn't run anymore than indicated in the other threads (around 6-9 sec.) The fluid levels fluctuate properly when car is off and pedal is pumped. The switch was replaced and the system pump bled and a new wheel cylinder put on. I just want to get this thing fixed b/c I am tired of driving a car that makes me say "Oh, sh*^!!!" all the time.