Powermaster problems.

[LT1ThirdGen]

Question for you Powermaster gurus.

Background: Just got my 87 GN back from a local shop after spring cleaning was done. Flushed everything, all fluids replaced, including brake flush/fluid. When I pulled the car into my garage and shut it down, I saw smoke coming from the drivers side of the hood. Popped it open and literally watched brake fluid drip out of the master cylinder, hit the manifold, and catch fire. Put it out without (hopefully) any damage. Upon inspection, I noticed that the master cylinder was filled damn-near to the top. I seem to remember that these units didn't get filled all the way up, so I pumped the brakes with the key off 10 times to depressurize the system, and took the reservoir cover off. The rubber gasket was soaked on top with brake fluid, so I assume it was overfilled and leaked out while I was driving. I siphoned out about 1/3 of the fluid from each reservoir and reinstalled the gasket and lid. Reservoirs are about half full now. Put the key in the ignition and fired it back up for a few seconds. Brake light stayed on. Shut it down and depressurized again, took off gasket and lid, and the reservoir on the passenger side had the same volume as when I closed it up, but the fluid looked milky as hell. I let it sit, and it returned to normal brake fluid color within ten minutes.

So, question: did I screw something up by pulling that fluid out? Should I put more back in, or am I in over my head jacking around with this POS Powermaster and just leave the damn thing alone and tow it back to the shop and let them deal with it?

Comments and advice would be greatly appreciated.

Thanks in advance.

 

[Venus]

There are two sides to the reservoir, driver side is for the circuits going to the front and rear brakes. The passenger side is for the accumulator ball. There is a marker inside of the reservoir that shows where the brake fluid level should be depending on if the system is pressurized or not I would recommend buying Richard Clarks PM book from kirban, every TR owner with a PM should have it IMO.

 

[BEATAV8]

When fully depressurized the levels should be at "max", near the top. Fully depressurized means keyed off and pedal pumped as many times as it takes to use up all power assist and get a hard pedal. Might be more than 10 pumps.

When you key it back on you can watch the reservoir side drop as the pump sucks the fluid down and pumps it into the accumulator. A good unit will suck down more than half of the fluid in the reservoir side, then it will shut off and stay off until you use the brakes again

 

[LT1ThirdGen]

When fully depressurized the levels should be at "max", near the top. Fully depressurized means keyed off and pedal pumped as many times as it takes to use up all power assist and get a hard pedal. Might be more than 10 pumps.

When you key it back on you can watch the reservoir side drop as the pump sucks the fluid down and pumps it into the accumulator. A good unit will suck down more than half of the fluid in the reservoir side, then it will shut off and stay off until you use the brakes again

Thank you both for the quick replies.

Passenger side is the one that turns milky. I just went through the depressurization process again.

Fill, turn key on until it drains out of passenger side, key off, fill some more. Pump only stays on for a few seconds, so I take that to mean that the accumulator is reaching its capacity.

This time, when I started it up, the brake light DID NOT come on, so I guess that's progress, but when I took the lid off, passenger side was milky again. Air? Not enough fluid on accumulator side? I put back almost all of what I took out.

 

[626gn]

The milky look is just air bubbles in the fluid. Normal.

Not sure if I'm understanding correctly, but, if you fill the passenger side reservoir up to the proper fill level with the system depressurized, you should not be adding more after that or it may overflow again. Once the system is pressurized the proper fill level (for passenger side only) should be no more than about a half inch from the bottom of the reservoir. Driver side reservoir should remain full. Looks weird to those not familiar with this particular system but that is the proper level.

 

[Buckshot G/N]

Fire... That is not good ,the shop definitely overfilled the reservoir. I'm wondering why you had a white milky substance on the reservoir side,
unless the brake fluid that was in your lines was contaminated,and when you depressurize the brake system it integrated with the new fluid.
You mention the brake light went out the second time you restarted the engine , that is good to hear .I would double check that brake switch that
plugs into the P/M ,an make sure no fluid is not near the plug in area.I would pump all the fluid out and refill it with a quality Dot4 fluid.
Venus mention to purchase Richard Clark and John Norton P/M Book .. { Spot ON }

 

[BEATAV8]

Do not add any more fluid after the pump runs.

If the accumulator is worn out or bad then it will not charge up with the correct volume of fluid. An empty fully depressurized accumulator in good condition will consume about 3/4 of the fluid volume from the reservoir side when the pump charges it up. The pump will need a good 15-20 seconds to charge up an empty accumulator with all that fluid.

If you see less than half of the volume of the reservoir being pumped in to the accumulator and the pump run time is very short then you need a new accumulator OR the switch is bad and it's turning off the pump at a lower pressure than its supposed to.

I would install a new switch and a Hydac accumulator. If it already has a Hydac accumulator on it then try just a new switch first. The Hydac accumulators have proven to be very reliable, much better than the original GM parts

 

[TurboDave]

Ya, the shop screwed you on that one. No shop should ever be allowed to touch the Powermaster system unless they have specific knowledge of its workings!! And the number of qualified shops to do that in the country can probably be counted on one hand. There's a thread somewhere here with pictures I posted on proper fill levels but I can't find it right now. I'll keep looking.

 

[TurboDave]

Here's some pictures to help you out. The first picture is what it would look like after you completely depressurize the system.

A few minutes later the air bubbles will disappear and you are left with clean liquid. Notice the fill levels. SYSTEM DEPRESSURIZED

Here's the proper fill levels when you key on and the system pressurizes its self.



Hope this helps

 

[TurboDave]

For some reason it's not putting the pictures in the way I posted them. Hopefully you can make some sense of it.