Think my PowerMaster may be dead, couple of questions

[cdub]

I had lost all breaks due to a mechanic overfilling the P/M Reservoir by not knowing to depressurize the acc before filling the bowl. I also had a leaking wheel cylinder at the right rear wheel, so I replaced the wheel cylinder, then followed zues' procedure to bleed the acc, the master cylinder, then vacuum bleed the brake lines to each wheel following the Right Rear, Left Rear, Front Right, Front Left order from gnttype.com's instructions, replacing all fluid in the system with valvoline synthetic. While I was filling the reservoir on the passenger side I pressurized/depressurized the system several times and although it did not always shut off within 20 secs after being depressurized, it always got a point where it was and shut off on the 2nd key on. Now the P/M motor is not shutting off at all. When I went to test drive it, the pedal was soft and was close to bottoming out, the brakes do work, I'm able to slow down fairly fast and come to a complete stop but the pedal does feel soft.

When I followed the gnttype diagnostics - Powermaster Diagnostics

The acc runs for more than 7 seconds so I go to step 2:

Step #2 - After accumulator Operation Test indicates seven seconds of more of motor operation.
A. Depressurize system with 10 brake applies with ignition off. Fluid level must be within gauge marks on the reservoir.
B. Turn ignition on and wait until motor shuts off.
1. If motor doesn't self cycle in 2 minutes without brake apply, proceed to (C).
2. If motor does self cycle, an internal booster leak requires replacing the PowerMaster assembly.

The motor does not cycle after running for 2 minutes after depressurizing the acc ball.

C. Install J35126 Tool and test to determine if fault is in motor and pump assembly or in the accumulator.
1. Remove pressure switch and install J35216 into switch port.
2. Reinstall pressure switch into J35126 and reconnect electrical connector.

I don’t have, or know what J35216 is. Is this something I have to order from a dealer or I can I get this at a regular auto parts store?

Also this is from the end of the same article:

Special Bleeding Instructions
A problem may be encountered in bleeding the PowerMaster if for any reason the pump has not been properly filled with brake fluid. If after any servicer new installation the pump does not circulate fluid after the motor has run for 20 secs, it may be necessary to reprime the pump. In order to reprime the system, the following steps should be performed:
1. Turn off ignition
2. Apply the brake pedal with medium pressure 10-15 times with ignition off to discharge pressure from the accumulator.
3. Clean and remove reservoir cover.
4. Disconnect the booster tube and nut assembly from the casting boss at pump outlet. Refer to illustration.
5. Wait for brake fluid to gravity bleed from the disconnected end of the tubing.
6. When brake fluid begins to flow, reconnect the tube and torque to 13 ft lbs.
7. Check the fluid level in the reservoir and add new brake fluid if needed. Reinstall the reservoir cover.
8. Turn on the ignition. The pump should properly circulate the fluid to the accumulator. The fluid level on the inboard side of the reservoir should diminish if the pump is working properly.
9. Continue with service manual bleed and fill procedure.


So my questions are -

1 - Could this be my issue, and reprimeing the pump will fix it?

2 - If I do this, do I have to rebleed the system? If yes from where? Start with the acc, then the Master Cylinder, then the lines? Or can I start somewhere farther down the line.

3 - If I do need a new P/M, where can these be purchased?

Thanks in advance for your help.

 

[buzzman]

i won't be much help, i have many of the same questions, mine went out last week, i did get bone from kirban, they said they just got six units in from cordone. cost was about 500 including shipping.

 

[cdub]

was that $500 for a reman'd PowerMaster?

 

[buzzman]

yes, and it does not look that good....hope it works, supposed to rebuilt by cardone which is what you want. Hey, have you ever tried to disconnect rod from brake pedal? Looks impossible.

 

[chopped39]

I would convert to vacuum for cheaper.This is my opinion but cardone sucks.I have replaced more rack and pinions and power steering pumps which all came to quality issues.I brought this up at a meeting my company put on with cardone.As soon as i brought it up they said 99% of returns were inproperly installed parts. So i walked out and grabbed 2 pumps that i had installed on a trans am that day. they installed new seals on rusted shafts.The guy was ready to kick my azz. they could not explain this to me. hopefully the parts you get are good.I myself converted to vacuum after wrecking my car because of that unpredictable pos .Just my 2 cents good luck with whatever you go with

 

[cdub]

How does the braking power of the vacuum conversion compare to a good working Power Master?

 

[49-blues]

I have a good used pump section if you need it.

 

[zeus87gn]

cdub,

If the fluid is going down on the ps of the bowl when the pump is running, you don't need to reprime it. It's pumping all it can.

Considering that you are not allowing the pump to run more than 20seconds, how long would you estimate that the pump would run if you let it go until it stops on it's own after that pump down of the acc? Do you feel this time would be consistant?

I can tell you this - if your motor isn't self cycling, the problem ins't in the main cylinder. If the time is consistant, it's most likely the pump. The special tool that is mentioned isn't available. I've tried to buy one outright from GM and they won't sell it. Most run of the mill auto parts stores don't know what a TR is...much less a PowerMaster.

Also, 7 seconds is the "perfect" guidline. Mine actually runs about 12 seconds now, but has no problems that I can detect. I have tested this with my old acc, and with one of the new style that is being sold now. Same time on both. I have no internal leaks...I have waited for over 10 minutes before.

Your soft pedal is most likely air still in the system. It's not easy to get it all out sometimes. That tech you mentioned probably got some in the main cylinder. Have you tried to bench bleed it?

Z

 

[chopped39]

How does the braking power of the vacuum conversion compare to a good working Power Master?

my car is not running yet so i do not know how mine is going to be.But a couple of guys i know did conversion and they love it. there is a lot of people that like power masters and hydaboost setups.After what i went through when i wrecked my car. I cant believe there was no warning .A guy pulled a u turn in front of me.I was doing 40+ mph. I hit the brakes and pedal was a rock.Needless to say i hit the guy. The hydraboost system is kinda the same .I hate when you have to rely on electric pumps or power steering pumps for stopping .I had a power steering pump go out on a big bread truck when i worked for chevy . I was going slow around a turn and shaft broke on pump and there was nothing .no steering or brakes.I know cars are smaller but at a 100+mph. your done.I cant imagine driving that gnx that was on here about a month ago.130mph and nothing.Can you say soil your shorts.

 

[cdub]

cdub,

If the fluid is going down on the ps of the bowl when the pump is running, you don't need to reprime it. It's pumping all it can.

I thought this was prob the case and the motor is pumping fluid from the p/s of the bowl to the acc so obviously this wasn’t the issue.

Considering that you are not allowing the pump to run more than 20seconds, how long would you estimate that the pump would run if you let it go until it stops on it's own after that pump down of the acc? Do you feel this time would be consistant?

I was not allowing the pump to run for more than 20 secs at a time, except for when the Powermaster Diagnostics said so let it run for 2 minutes and see if it self cycled, it ran for 2 mins without self cycling and then I shut it off.

The time for the motor to fully pump up the acc has been inconsistent, sometimes taking 2 20 second runs of the motor even without depressurizing the acc, and other times running past 2 mins after depressurizing the acc.

I can tell you this - if your motor isn't self cycling, the problem isn’t in the main cylinder. If the time is consistent, it's most likely the pump. The special tool that is mentioned isn't available. I've tried to buy one outright from GM and they won't sell it. Most run of the mill auto parts stores don't know what a TR is...much less a PowerMaster.

Yes I tried every place I could with no luck. The diags did provide and alternate method if the tool was unavailable which I did follow

E. NOTE: J351226 tool in (2C) is the best method; however, if it is not available, an alternate method will help to determine fault between the pump and motor assembly and the accumulator.
1. Depressurize the system with 10 brake applies with the ignition off. Turn ignition on, and check the time from motor start to motor shut off.
2. If time to motor shut off is more than 15 seconds, replace motor and pump assembly, and then retest accumulator per Accumulator Operation Test. If time is seven seconds or more, also replace the accumulator.
3. If time to motor shut off is less than 15 seconds, replace accumulator, and then retest motor and pump per Accumulator Operation Test. If time is seven seconds or more, also replace motor and pump.

Given the long times my motor is running it looks like I need to replace the unit to me.

Also, 7 seconds is the "perfect" guidline. Mine actually runs about 12 seconds now, but has no problems that I can detect. I have tested this with my old acc, and with one of the new style that is being sold now. Same time on both. I have no internal leaks...I have waited for over 10 minutes before.

Good to know that over 7 secs isn’t an automatic dead unit. When you say you "have waited over 10 minutes before" what exactly do you mean? Was this after servicing the unit? Or was this just a random occurrence of the pump taking a long time to pressurize the acc?

Does the fact that I still have decent braking mean my unit might be ok?

Your soft pedal is most likely air still in the system. It's not easy to get it all out sometimes. That tech you mentioned probably got some in the main cylinder. Have you tried to bench bleed it?

Yes this may be the case, I did bleed and flush the entire brake system, did the acc 1st, then bench bleed the Master Cylinder, then the brake lines using a vacuum pump. One issue I did have was the right rear bleeder screw was completely inaccessible so I skipped this wheel rationalizing that the rear brake lines split on top of the diff housing and the likelihood of any air being in the lower line to the right wheel cylinder was low, of course air may have been forced to this part of the line I know.

I have purchased a new wheel cylinder for this wheel too, and will be replacing it today so that I can properly bleed all wheels.

I have ordered the parts for a vacuum conversion as well, should be in today. At this point I'm loosing confidence in the P/M due to the multitude of issues I see people having with it. I have had the GN since 1998 and never once had a brake issue, it always stopped on a dime for me. But now it seems it is my time to deal with a flakey P/M, possibly caused by myself, or my mechanic, leaving the pump running for too long without knowing about the 20 sec rule.

 

[zeus87gn]

Sorry for the late response. Been hectic. Had to think a bit.

I was not allowing the pump to run for more than 20 secs at a time, except for when the Powermaster Diagnostics said so let it run for 2 minutes and see if it self cycled, it ran for 2 mins without self cycling and then I shut it off.

So the actual motor was humming for 2 minutes?! Are you sure you dont mean that it was just sitting there not making a sound waiting for the switch to kick it in when the pressure got low?

The time for the motor to fully pump up the acc has been inconsistent, sometimes taking 2 20 second runs of the motor even without depressurizing the acc, and other times running past 2 mins after depressurizing the acc.
...
Yes I tried every place I could with no luck. The diags did provide and alternate method if the tool was unavailable which I did follow

E. NOTE: J351226 tool in (2C) is the best method; however, if it is not available, an alternate method will help to determine fault between the pump and motor assembly and the accumulator.
1. Depressurize the system with 10 brake applies with the ignition off. Turn ignition on, and check the time from motor start to motor shut off.
2. If time to motor shut off is more than 15 seconds, replace motor and pump assembly, and then retest accumulator per Accumulator Operation Test. If time is seven seconds or more, also replace the accumulator.
3. If time to motor shut off is less than 15 seconds, replace accumulator, and then retest motor and pump per Accumulator Operation Test. If time is seven seconds or more, also replace motor and pump.

Given the long times my motor is running it looks like I need to replace the unit to me.

Wow. Even with an inconsistant time, that sounds like a dead pump to me.

Good to know that over 7 secs isn’t an automatic dead unit. When you say you "have waited over 10 minutes before" what exactly do you mean? Was this after servicing the unit? Or was this just a random occurrence of the pump taking a long time to pressurize the acc?

Does the fact that I still have decent braking mean my unit might be ok?

When you do the leakdown test, you let the acc pump up and then let the unit sit still with the key on. If there is an internal leak, the pressure will bleed down and the motor will turn on/off by itself. If this happens in less than 2 minutes (by the book) you have an internal leak and the main cylinder needs repair/replacement.

It is this sit still time that I have waited for over 10 minutes with no motor activity. Get it?

Your unit may be Ok if your "sit still time" doesn't have any motor activity. BUT, considering it might be original to the car, you may want to replace/rebuild it anyway.

Yes this may be the case, I did bleed and flush the entire brake system, did the acc 1st, then bench bleed the Master Cylinder, then the brake lines using a vacuum pump. One issue I did have was the right rear bleeder screw was completely inaccessible so I skipped this wheel rationalizing that the rear brake lines split on top of the diff housing and the likelihood of any air being in the lower line to the right wheel cylinder was low, of course air may have been forced to this part of the line I know.

I have purchased a new wheel cylinder for this wheel too, and will be replacing it today so that I can properly bleed all wheels.

I have ordered the parts for a vacuum conversion as well, should be in today. At this point I'm loosing confidence in the P/M due to the multitude of issues I see people having with it. I have had the GN since 1998 and never once had a brake issue, it always stopped on a dime for me. But now it seems it is my time to deal with a flakey P/M, possibly caused by myself, or my mechanic, leaving the pump running for too long without knowing about the 20 sec rule.

Keep in mind that PowerMasters are a high maintainence unit. If not properly cared for over it's life, it will fail. Many of the horror stories you have read were probably caused by improper maintainence. Most don't change thier brake fluid. Mistake #1.

There is also another theory that I have in that the PowerMaster was just not design to last that long. 20yrs is longer than the typical designed lifespan of most vehicles. Ask any GM engineer and he will tell you. They don't make cars to last that long....intentionally. Because they want to sell you a new car. Food for thought.

 

[davidgn214]

just like chopped39 said i would convert to booster its easy less problems... all you need is the booster and pedal off ahy 87 88 monte carlo and vacum block im sure you can find a booster for under 100