hey Zeus of the almighty powermaster?

[300kGN]

how tired are you from all these power master q&a's?
Mine's been on the brink for awhile. sat in storage for some years, during which the accumulator bled down pouring fluid over the assy. started popping fuses. pump runs after one brake apply. now it can't keep a fuse at all.
in a moment of brilliance, I jumped the fuse with a momentary switch, trying to let the smoke out I guess. the pump strains to a hault just after the brake warning light goes out. ever heard of the actual pump rotor corroding/siezing? or could it all be the ball is requiring too much force to pressurize? went through the spec test when this all started, seemed kind of inconclusive.
also, still has an iron prop valve. is brass still available or still applicable?

props on the 200k milestone!
Andy.

 

[zeus87gn]

Yes, I am the PowerMaster!

The poor ol Powermaster system...
How I wish I could punch the GM designer in the face for not telling the service guys how to take care of these things! I guess they just wanted to keep replacing them. Had to be a $$ issue. GM is all about service, its a big $$ maker for them.

If you're popping fuses, you definetely have a problem. The motor heats up from running too much and pops the fuse every time.

Have you timed it with the diagnostic procedure yet? Brake System
--->Tell me the time to pump up the acc, and the time until the motor self cycles and I can tell you more. I could guess you have a combination of a dying acc and a leaking cylinder. May be on it's last leg, but I won't say anything until you can give me some times.

P/M's dont like to sit. They like to be used. Your acc bleeding all over was simply that the bowl was overfull. They will bleed down over time if not used (it's not a "perfect" system), and if the bowl is full when this happens you will see just what you did. The fluid has to go somewhere.

The pump motor could sieze if it get's too hot. It isn't designed to run for long. If the system is up to par, it doesn't have to.

I think the prop valve is a matter of choice. I believe the brass ones are available. I still have the original iron one (just figured it out) and don't have problems....yet. I will change to the brass at the next service interval. It is really a better design.

Are you really up to 300k miles? Or is that $300k?

 

[300kGN]

when I followed the test, I think it was about 8-9 sec for the pump cut-off(8mos ago). This weekend I had to put the momentary switch in place of the fuse, they pop immediately. Yesterday I could hold the switch on til the light went out. Today, it won't even turn the light out. I can hear the motor struggling towards the end. Then it sounds like a relay clicks the motor shuts off and the light is still on.

I've had the car about 8yrs, I think I replace the acc once-although that may have been on a customers Plymouth mini-van- can't remember.

When I bought it, the original owner claimed 250k miles and handed me a 3" thick folder full of every paper for every little piece/thing he put on the car/did/happened to the car. 6 trany overhauls, 1st 2 under warranty. Theft recovery in KY. yadda-yadda.
We ended up going to the GS Nats together (he bought a T-type), where he confessed it was probably closer to 275k when he sold it to me. He never intended to sell the car. Several VDO speedos later...the mileage, unlike everything else, is really undocumented.
Andy

 

[zeus87gn]

300,
I had to think about this one for a while...

If you are blowing fuses right off, even with the motor in a cool state, it's probably gone. With all the possible miles, it's most likely worn the brushes out which are now shorting and blowing the fuses. Won't even begin to build pressure because it won't spin enough before popping the fuse. Otherwise the short could be in the wiring. You can test this theory if you have a DMM.

Your time from a few months ago says your acc was just beginning to get old. Not a big deal.

Your vehicle has many many many many many many miles (I feel your pain). Do you know if the P/M has ever been changed/serviced? Maybe a note or receipt in that stack of paperwork? Have you ever changed/flushed the fluid?

As much as I hate to say it, it may be time to bite the bullet and do an all out replace. There is another thread that a fellow has said he has found a rebuild kit for $20. If that pans out, you may can rebuilt for less than an entire unit. Just rebuild the cylinder and replace the motor.

Z

 

[300kGN]

the pm was replaced in 1989 with an entire unit supplied by the other owner, I don't know where he got it. Only found 1 acc reciept. I've never flushed it. Somewhere I saw a site that sells new motors, somewhere else the rebuild parts.
At any rate, the gremlins vacated. Not blowing fuses today with a pump up time of 15 sec. I'm going to look into some parts 1st.

Thanks for the help

 

[zeus87gn]

15 seconds is too long. Should be half that.

If the 15 seconds is relatively consistent, try an acc first. If that puts the pump up time back down under 10s, you should be good for a while.

BTW, your PowerMaster likes clean fluid.
As you haven't changed it in 8yrs, you may have to change it again in 6 or 8 months after changing it this time. Vaccum pumps are fabulous for flushing in your situation. Keep that fluid clean!

Good Luck!

 

[GNRick]

I realize I'm not Zeus, grandmaster of the powermaster but if a new accumulator isn't readily available in the parts box, I wouldn't pay the $189 for a new one. Given the history of this powermaster, I would splurge for a new one with a lifetime warranty. Just my .02.

 

[zeus87gn]

Rick,
Thanks for the compliment. I hope I am actually helping others.

From my experience, and from what I have seen on the P/M's that I have worked on, and from the multiple brake systems that I have worked on throught the years, and give the condition and problems that 300 has had, I will agree with you. But without actually putting my hands on his particular P/M, it is really a diffucult call. The decision is completely up to 300.

Brakes are not something to guess with. They MUST be in top condition.

Z

 

[300kGN]

researching availabilty of the cardone remans. seems they have jacked the price to meet our demands, $350 for the whole unit. Judging by the sound of my motor just before it shuts down, and the possibility of brake fluid intrusion into the windings after the accumulator bled down, the reman unit is sounding pretty good. Probably going to switch to the s10 cyls and the brass valve at the same time. It's getting WAY too difficult to hold 10psi at the line.
Z,
Also noted in older post's you state to use DOT3. DOT5 not ok for the bladder? Or sticking to what's known to work properly?
Thanks for the input,
Thanks for the input,

 

[GNRick]

researching availabilty of the cardone remans. seems they have jacked the price to meet our demands, $350 for the whole unit. Judging by the sound of my motor just before it shuts down, and the possibility of brake fluid intrusion into the windings after the accumulator bled down, the reman unit is sounding pretty good. Probably going to switch to the s10 cyls and the brass valve at the same time. It's getting WAY too difficult to hold 10psi at the line.
Z,
Also noted in older post's you state to use DOT3. DOT5 not ok for the bladder? Or sticking to what's known to work properly?
Thanks for the input,
Thanks for the input,

And, don't forget if you buy from Kirban, he gives $75 credit or cash. I think he is higher than $350, though. Did you get that price from Autozone or Advance?

 

[zeus87gn]

Kirbans is $419.95 by thier web site.
$75 core for your old one

419-75= $344.95 (+shipping I'm sure). D@mn good deal. I may have spent that much rebuilding mine when all was said and done. But I got my rebuild kit for $40. Spent a good afternoon doing the rebuild to the letter. This one is ready to go.

300,
DOT4 is my recommendation. Works great and will mix with the old #3. I have been using the Valvoline synthetic for years with no apparent ill effects. If you have the old #3, you really won't see the best performance until you flush the next time. After you install your fresh P/M, do your bleed/flush. Drive it for 6 months and do it again. Then you are good to go for a year or 2. Done it many times.

#5 is silicone and isn't very compatible for automotive braking systems. It doesn't mix with 3 or 4 and is rediculously expensive...like $20/qt. You have to flush your entire brake system with alcohol to remove all the leftovers if you want to switch to it. I remember reading somewhere that the additives in that fluid don't do well with the material in the seals . Not worth the bother in my opinion.

 

[GNRick]

Who has the rebuild kits?

 

[zeus87gn]

Karps in California says they have them but want over $200 for them.
A fellow in another thread says he found them at the AutoZoo for $20. He hasn't come off with a part number yet but was supposed to have picked it up yesterday. We'll see.
GM discontinued them a couple of years back. It's been a problem ever since.

 

[GNRick]

Kirbans is $419.95 by thier web site.
$75 core for your old one

419-75= $344.95 (+shipping I'm sure). D@mn good deal. I may have spent that much rebuilding mine when all was said and done. But I got my rebuild kit for $40. Spent a good afternoon doing the rebuild to the letter. This one is ready to go.

So did you just rebuild one with an old kit that you bought years ago for $40?

 

[zeus87gn]

So did you just rebuild one with an old kit that you bought years ago for $40?

I honestly don't remember the price, but basically yes.

Would you like to hear the whole story?


If I can remember.....7yrs ago I had the hard pedal symptom - replaced the accumulator, all is well. A short time later (like a month) I had problems with the hard pedal again. Sometimes firm sometimes so-so, never really consistent. Replaced the pressure switch thinking it may be bad and it changed nothing. The P/M gave up on me totally pulling into my driveway and I just about cr@pped my pants from almost putting my wife's GN in the ditch because I couldn't stand on the pedal hard enough. Coincidentally I was returning from the local Buick dealer that told me the brand new pressure switch was bad. (No more stealerships for me)

Got on the internet, found GNTType.org information. Ran the diagnostics, found the internal leak. Bought the thick book (that doesn't seem to be in circulation any more) and the cylinder kit and went to town. Found a completely blown apart oring on the power piston. Came out in 3 pieces.

Got it back together and still wouldn't time out. Only thing left in the high pressure side was the motor so I got one of them from Hank and haven't had a problem since. Ended up a total rebuild (new pump) except for the orings that attach the bowl to the cylinder and the hose on the pump.

I now have a backup acc ball on my shelf.
I still have to replace the prop valve.
My P/M and stock brakes are still better than any other vehicle I own...or have ever driven...under normal driving conditions.

I never did add it up to get a total price, but with the cost of the acc now the Kirbans price isn't too bad. My acc only cost $70 and I think Hank was ony charging $120 for the motor then.

Yes, been there - done that.

 

[GNRick]

Interesting story. I also had a hank Terry pump and a new accum., but my master cylinder was leaking out the back by the firewall. I bought a new one on Ebay for $130 and all is good for now.