powermaster question

[grocerygetter]

My car has had the brakes (rotors, pads, s10 wheels cyl and new shoes) rebuilt. It stops like a champ with no flukes under normal driving. If you get in an emergency situation, and hammer the brake, the pedal is stiff as crap for about 1.5 seconds and then it brakes like a hammer. Is that an accumulator issue?

 

[aminga]

The accmulaor us usually acompanied by the brake light coming on breifly when you initially apply the brake. Andd it would happen at every first brake application because because there isn't enough fluid volume to keep up with the pedal moving forward.

 

[grocerygetter]

if kyou ease into the brakes it isn't a problem. Anytime you hit them HARD or the first time you hit them in the morning when starting the car the pedal is rock hard. I'm not getting a light though...wonder if my idiot-light-bulb is burned out LOL.

 

[aminga]

Still it sounds like the accumuator is the most likley culprit.

Check a few things.

1) Does the motor run for about 15 seconds when you turn the key on?
2) Does the hard pedal go away when you hear the motor kick on?

Also turn the switch on let the systme pressurize and sit. An internal leak in the master cylinder will show up as a motor that runs perodically when no one has hit the brakes.

 

[grocerygetter]

1 & 2 both yes.
and...I don't remember the motor running again after initial.
so....me bidding on this accumulator is a good thing then?

 

[zeus87gn]

Accumulator is typically the first to go in these systems. They are not too deadly expensive and simple to replace.

I had the same symptoms as you, replaced the accumulator and trouble went away....for a while. I ended up having the internal leak and doing an entire rebuild. You really need to be sure what's happening.

Check the troubleshooting here...
http://www.gnttype.org/techarea/brakes/brakespage.html

It's a good guide to make a proper determination of what's at fault.
Know the system as best you can if you want to keep it alive.

 

[aminga]

And if it turns out to be an internal leak don't just replace the PM unit. It can be rebuilt in an afternoon for < $50.

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

 

[grocerygetter]

I'm bumping this...I put an accumulator on when I did this thread and everything has been fine. over the last few months I can feel the PM pulsing through the pedal when at a stop and yesterday this whole stiff brake pedal at an emergency stop happened. If you ease into it, it works fine...but if you hammer it you have no brakes for a couple of seconds...then its alright.
so...suggestions? I'm an inch from putting a hydroboost set up on there.

 

[grocerygetter]

bump...for those that search...through the help of Brian Weaver I got it licked this time.
Once again, accumulator. This time I got a new one instead of one off of a 130k mi car. So I really think the acc. balls have about 125-150k life. Also, my system was sucking in air through the prop. valve. I had the iron one...I now have a nice brass one.

 

[Red Regal T]

How much do they run, and does Brian have more? I have a friend who gets a brake-lite flash everytime he hits the brakes. He figures it for the ball, and I guess it is.