What's wrong w/ my brakes?

[Ken Cunningham]

My master cylinder has been making a whining/groaning sound for a couple of months now. No loss of braking and the dash light does not stay on. I don't know much about our 'Power Monster' system, but I believe that the accumulator ball fails silently so I suspect the pressure switch.

After I depressurized the system w/ 10 pedal pumps (key off) I checked the fluid. The fluid in the inboard section of the m/c (the long chamber, don't really know how else to describe it) was cloudy with tiny bubbles. It cleared up in a few minutes. The fluid in the two outboard chambers was clear but below the dividing dam, so I brought the level up a bit.

Does my description help anyone with a guess about what's failing on my Power Monster?

 

[Steve Wood]

did you follow the trouble shooting links provided under brake maintenance on this page?

http://www.gnttype.org/techarea/brakes/brakespage.html

 

[Ken Cunningham]

Thanks for the link, Steve. Actually I did follow the troubleshooting chart as best I could. But my ignorance of brake systems in general and the PM in particular is enormous. F'instance, when the diagnostic says "Recheck fluid level on booster side" I'm not even sure which side is the booster side. I see 3 chambers in the master cylinder, one inboard and two outboard (which connect through a low dam).

Anyway, I didn't see any diagnostic for an intermittant whine or groan. If my brake light doesn't stay on (which it doesn't) then the diagnostic chart just drops me off at the "System OK" node. But I know that my system is not OK, and I'd like to fix it before the brakes turn rock hard as I approach a red light

 

[Steve Wood]

Might be getting time to replace the pump/motor?

 

[Ken Cunningham]

Guess it's time to see if Autozone still carries those 'lifetime' guarantee master cylinders!

 

[86underboost]

When i throw them monsters in and turn the key on for the first time, the motor sucks fluid outa the passenger-most resevoir. I'm gonna say that's the booster side. I still don't understand how these things work (or don't work), but i know i can have em out and in lickity split!!!!

 

[Ken Cunningham]

According to the Autozone web site, they do not have any of our Power Monsters in stock (52-9702). I'll try a store to see if the story's any different, but it doesn't look good.

 

[wallballs]

Guys,
Thanks for all of the information. My car has suffered from a soft pedal for ever. Long enogh so that I never ran it hard. I know the combinatin valve and power switch have never been changed by a dealership. I still have the cast iron valve on my car. I assume from looking at the recal information that a dealership will still perform the recall. Correct?

 

[Chuck Leeper]

Originally posted by wallballs
Guys,
Thanks for all of the information. My car has suffered from a soft pedal for ever. Long enogh so that I never ran it hard. I know the combinatin valve and power switch have never been changed by a dealership. I still have the cast iron valve on my car. I assume from looking at the recal information that a dealership will still perform the recall. Correct?

You tell the difference on the switches by the color. The early sw is black body, while the replacement is gray. If the car has the gray sw, then it's the latest.
As for the combo valve, there's some confusion as to what cars get that change.. A search in the archives should produce some added info.

 

[wallballs]

The recall information states for all cars to be inspected. Cars with the old switch should be repalced. Cars with the cast iron conbination valve are to be replace with a brass combination valve. That sounds pretty cut and dry. What gives?

 

[Chuck Leeper]

Cut and dry this!

If that's what it says, have the car inspected and be done w/ it....