Clutch Slave Cylinder

[SuDZ]

Ok,

I finally got the hose that I was waiting on to replace my clutch slave cylinder. I removed the old cylinder and hose and reconnected it with the new one. I had a few leaks that were taken care of when the hose was not connected tight enough. But now when I pump the clutch pedal it does not seem like anything is happening. The rod does not move that sticks out of the slave and no fluid seems to be leaving the resevoir.

I am trying to figure out why this would be happening. Does anyone know of a reason? There does not seem to be leaks anywhere else now.

SuDZ

[ZmeFly]

what year is your vehicle?

did you make sure to bleed the mc and the slave?

let me know

[Bambikiller240]

You only need to bleed the slave cylinder on a stock 240/260/280Z as there is no bleed screw on the clutch master cylinder.

[Salacious Crumb]

You might want to remove the mc and bench bleed it before reistalling and bleeding the system at the slave.

[Bambikiller240]

Originally posted by Salacious Crumb

You might want to remove the mc and bench bleed it before reistalling and bleeding the system at the slave.

there is NO bleed screw on the clutch master cylinder!!

[Zs-ondabrain]

Hey Carl,

Is that steam coming out of your ears?

[Salacious Crumb]

I didn't say bleed the mc from a bleed screw on it. I said remove it and BENCH BLEED it. This is a standard practice when installing a brake or clutch mc and ensures that no air is trapped in the mc bore. It would simply be wise and methodical to perform this action in this situation since bleeding at slave was stated as not having worked.

[SuDZ]

To answer a few of the questions...

It is a '74 260Z.

I did not do a bench bleed.

How do you go about doing a bench bleed? Is there much more to remove from the MC to do the bleed that just undoing the rigid cable under neath and then the two bolts that hold it into the body itself?

SuDZ

[mwz]

How do you go about doing a bench bleed? Is there much more to remove from the MC to do the bleed that just undoing the rigid cable under neath and then the two bolts that hold it into the body itself?

You're right, and then there is a pin that secures to the clutch pedal assembly. You'll need to stand on your head to see this under the dash.

Personally, IMO unless you replaced the MC I don't think it's necessary to remove it and bench bleed it. It all sounds quite normal to me (that you replaced the slave and now pumping the pedal shows no "action" at the slave). It will take quite a few pumps and some time spent bleeding the air out before the slave will start acutally moving. Air will not let the slave piston move, you'll need to get the air out by bleeding (the conventional way should work).

Hope it helps.

Chloe

[Bambikiller240]

"Bench bleeding" is not really bleeding, it is simply filling the cylinder bore with fluid. You mount the cylinder in a vice and add fluid and actuate the cylinder until fluid pumps out of the fitting for the hard line. It does not ensure that no air is trapped in the cylinder, as there is very little pressure build up to force out trapped air. It can help (can't hurt) but normally is of little benefit IMHO. Bleeding at the slave is normally sufficient 95% of the time. After "bench bleeding" you will still need to bleed the system at the slave cylinder. Good Luck

[SuDZ]

Just figured I would update this thread a bit. I was still having problems getting pressure through the lines. So here is what I did and maybe it will help someone else.

I just removed the slave cylinder and left the hose hanging. Then I would cover the hole on the tube with my thumb and have my helper pump the clutch. Eventually it would build pressure and blow my thumb off the hose. Then I would have them stop, recover it with my thumb and do it again. I did this over and over until there was fluid flowing out the hose with every pump. I was never so excited to be gettting myself covered in clutch fluid in my life.

SuDZ

[MikeW]

Originally posted by SuDZ

Then I would cover the hole on the tube with my thumb and have my helper pump the clutch. Eventually it would build pressure and blow my thumb off the hose. Then I would have them stop, recover it with my thumb and do it again.

I wonder why that method worked but the normal bleeding procedure didn't. It doesn't seem all that different to me - using your thumb instead of the bleed screw.