Bleeding clutch slave cylinder

[sagekh]

So around the time I bought my car about a year ago, my clutch would stick sometimes and I’d have to pull it back up with my foot when I shifted, then one day I went out and it just stuck to the floor. No big deal, bled the clutch slave cylinder and the clutch felt great again. Fast forward to almost a year later and thousands of miles, clutch is sticking about half way through again, no biggie time to bleed again. Only this time, I opened the bleed valve and some fluid dripped out, then ceased. Now the clutch pedal forces itself back down to the floor when pulled up every time, although every time it’s depressed I can hear air being relieved through the slave cylinder bleeder screw, but no fluid yet after hundreds of times pumping the clutch and opening and closing this damn screw. Nothing even happening in the clutch fluid reservoir, whole time full. I went out and rented a brake vacuum bleeder kit although I’m not sure how to use it to bleed my clutch I’m sure it can speed up this process. Would an excessive amount of air in the system cause the pedal to force itself to the floor without being touched?

[mwolvinm]

I wouldn't think air in the line would force the pedal back down, but a bad master or slave cylinder might.

[sagekh]

I wouldn't think air in the line would force the pedal back down, but a bad master or slave cylinder might.

Went ahead and replaced the slave cylinder again to no avail. I did however make some progress today.
It seems as if I won’t need the brake bleeder after all, as today after opening the clutch reservoir, the slave cylinder valve, and pumping fluid through the system I’m finally getting fluid bleeding through the slave cylinder, and it’s partially engaging again. The clutch has risen a little and goes up and down a couple inches or so but still forces itself back down as far as it goes which I simply don’t understand what would cause this. A new master cylinder was also put in last year already. Gonna keep trying this tomorrow and hopefully will have a running car.

[mwolvinm]

I read on one of the Z31 information pages last night that a blocked master cylinder will cause these symptoms. I think you need to change that. Since the master cylinder is relatively new, you may want to clean or change the lines as something is causing a blockage.

[albionwanderer86]

Have you tried bleeding your clutch dampener? Follow the line from your clutch slave cylinder up to the frame rail, and you should see it there.

[tcfs]

Have you tried bleeding your clutch dampener? Follow the line from your clutch slave cylinder up to the frame rail, and you should see it there.

Or delete the clutch dampener altogether. That's what I did when I was having trouble bleeding a new slave cylinder. You can replace the clutch dampener with a 280zx brake hose. I don't remember which year or position of the 280zx brake hose, but it is a plug and play deal.

[sagekh]

I ended up deleting the dampener with a 240sx clutch line that runs directly from the master to the slave however my clutch pedal still forces itself about half way to the floor and I have to hold it up with my foot while driving.

[Dunkine]

Did you replace or rebuild the clutch master cylinder? Sounds like it's bad.

[sagekh]

You could be right however as far as I’m aware the previous owner put a new master cylinder in not too long before I purchased the car. Might totally be worth a shot though