Recenly replaced my wheel cylinders do from one popping, my pedal has never been stiff on the car and always has a whoosh sound when i press it to the floor. Well anyways lastnight the driver side wheel cylinder blew again So what are some ways to tell if the master cylinder is my problem?

Thanks

 

Look at what part failed.

Q: Did the wheel cyl fail?

A: The wheel cyl is the problem.

No the master cyl isn't your "problem"... although of course, that's no guarantee it's not bad.

About the only way for the wheel cyl to "pop" is for the rear brakes to be assembled inadequately. Put the cyl back together (probably nothing wrong with the parts, but for $10, what the hey, you could replace it again anyway, if you want) and this time when you put the drum back on, adjust the shoes out as far as you possibly can and still be able to get the drum to go back on over them. Do both sides that way. Might make an AMAZING difference in how hte brakes feel. And who knows, your parking brake might even start working.

 

I had already done the rear brakes and adjusted them properly, E-brake does work so im not to sure whats causing the brake pedal to be spongy and go to the floor. But what are some ways to test the M/C??? Also no matter how many times i bled the brakes the brake light would not shut off. I disconnected the wire on the p.valve and the light shut off.

 

It sounds like either there is still air in the line or a leak. Since there's fluid on the new wheel cylinder and it's not likely a new one would pop, I'm guessing the brake line isn't on tight enough.

Have someone press down on the brakes while you are looking at the back of the brake fitting and see if you can find the leak. Note the brake drum should be on/installed else the cylinder will get over extended and it will pop.

 

I'm guessing that there's some history behind this that you haven't admitted to yet. Which makes a difference; asking the question in a vacuum, without teling how you got to where you are, will make just about anything we can guess out out here on the other side of your monitor, just a guess.

Specifically, did the MC ever run dry? EVER? Honestly? ... If it did, it has air in it, above the points where the lines attach. So, you can bleed a gallon of fluid through it every day from now til Doomsday, and twice on Sundays even; and that air trapped up in the top of it in there will NEVER EVER come out, until you "bench bleed" the MC.

 

That did happen because i had to drive it home and ran dry. Would that trip the brake warning light? Its never been the same since.

 

Of course it would....

The brake warning light switch is operated by pressure difference between the fronts and the rears; i.e., when one produces pressure, and the other does not. Most likely, your MC has air in the front half, which is the half that drives the rears; with air in there, it can't make pressure, while the fronts (rear half of the MC) evidently do; so, the switch gets tripped.

Which incidentally, also indicates that the MC can't "blow" a WC; it's not even building up pressure.

As said, the ONLY WAY for a wheel cyl to "pop", is for the shoes to be inadequately assembled, and not adjusted up high enough. Protest as much as you like, but the parts and their actions don't lie.

Bench bleed your MC to get ALL the air out, and adjust your rear brakes as I described. Then the next time you step on the brakes hard, the switch will be reset by the EQUAL pressure in the front and the rear systems.

 

would a rusted out backing plate cause the wheel cylinder top pop out the piston? It seems really loose.

 

Probably not; unless it was SO rusted that the WC could about fall out.

IIRC the WCs in these cars are sort of D-shaped, and are held in by a big round clip. With those, they don't ever fit real tight, and can always wobble around a little bit even when everything is brand new.

 

Well on the driverside i didnt even have to take the clip off to get it out

 

Well it sounds like you need new backing plates then.

 

That has to be it then, because it wheel cylinder is sitting to low thus causing it to pop off. Well thanks for the help guys