Replaced master/slave cylinders - still no pressure

[kegworth]

So I replaced both my master and slave this morning... filled the reservoir and pumped the clutch. There is def fluid in the lines. But i can't get any movement out of the slave. The master is connected to the clutch properly. I'm just wondering if i installed the slave incorrectly. When i installed it, the push rod was depressed, it seemed to be the only way for it to fit. So re attached the return spring and all that biz. tightened the adjust nut to where it pushes lightly against the tranny lever. i just don't know what's going on... could the pressure plate in the clutch be busted? any help greatly appreciated.. see pics

[Bruce Palmer]

Did you bench bleed the MC first? If you have air in the MC you can pump til your eyes cross and nothing will happen down below regardless of how what is hooked up to what.

[kegworth]

How do i bench bleed it?

[Bruce Palmer]

Pump and crack the bleed screw on the side of the MC. This will allow hydraulic fluid to replace the air in the cylinder resulting in some push down below...... eventually.....

Treat this process like you would if you were treating the whole system only look at it as one system upstream from there. Pump up some pressure and crack the bleeder and close when the pedal is down repeat until all the air is evacuated. Repeat at the slave until all the air is out of the whole darn thing..

[kegworth]

you are talking about bleeding the clutch master right? So just slightly unscrew the hydraulic line on the side of it and pump the clutch?

[Zed Head]

You don't want to "pump." Press down, hold down while releasing the bleed screw, tighten bleed screw, then release pedal. That's why an assistant helps. If you let the pedal up with the bleed screw open, air will suck back in to the lines, whether working at the master or the slave. Things will get worse because you pump fluid out and let air in.

[kegworth]

Ya i understand the bleeding process now. So i engaged the clutch pedal... locked it into place. unscrewed the bleed nipple. no fluid comes out. is it possible one of the parts (themaster or slave) are bad that i got from the auto parts store? i even unhooked the hydraulic line from the master and pumped the clutch, couldn't even get any fluid out of the hole with the hose disconnected... should i? or does it have to be tapped in order to flow fluid?

really freaking stumped. i appreciate you help.

[doradox]

Ya i understand the bleeding process now. So i engaged the clutch pedal... locked it into place. unscrewed the bleed nipple. no fluid comes out. is it possible one of the parts (themaster or slave) are bad that i got from the auto parts store? i even unhooked the hydraulic line from the master and pumped the clutch, couldn't even get any fluid out of the hole with the hose disconnected... should i? or does it have to be tapped in order to flow fluid?

really freaking stumped. i appreciate you help.

Check the adjustment of the pedal free play. If the rod from the pedal to the MC is too tight it will hold the piston in the MC too far forward, covering the hole that lets fluid into the cylinder, and the fluid in the reservoir will not fill the cylinder.

If everything is OK you should actually just be able to loosen the bleeder screw on the Slave and eventually fluid will run. Gravity bleed. I always do it that way.

Steve

Edited October 9, 2010 by doradox

[kegworth]

i completely took the master out.. and pumped it by hand with the reservoir filled.. couldn't even get fluid out the hole for the hardline. should i?

[doradox]

i completely took the master out.. and pumped it by hand with the reservoir filled.. couldn't even get fluid out the hole for the hardline. should i?

Yes, it should just run out without even pumping. Sounds like something blocking the port between the reservoir and the cylinder. Is the piston returning all the way back up against the clip that holds it in? You'll have to remove the boot to see.

Steve

[kegworth]

FIXED IT!

i had taken everything back out preparing to take the master back to the auto store... when it hit me. First of all, as we all know you have to use the old push-rod for the master cylinder cause the new one is too short. But upon further inspection, the old rod has about a 1/2 inch extension on the piston side of the rod. So when its hooked up and the clip is in place, it wouldn't let the piston fully return "home" even though it appeared that it did. So i dremeled it off so that it sat flat at the head of it. And what do you know... fluid a flowin. So i bled the system about 4 times myself (pita) and voila. it works. only thing i think i'll need to do is adjust the slave nut. the engagement/disengagement is a little close to the floor. That's where i would fix that correct?

thank you very much for all of your help guys.

[sblake01]

I guess you could adjust the free play at the slave if the slave is adjustable. The later cars don't have a provision to adjust it there so you must be working on the 71. I always adjusted the free play at the push rod head/lock nut behind the clutch pedal. And I use a power bleeder which makes clutch bleeding as well as brake bleeding so much easier.