Problems bleeding hydraulic clutch

[Stevo F]

I went ahead and flushed out the brake fluid on our 2005 Impreza OBS today with no issues (using a one man vacuum bleeding tool). Afterwards, I said, "hey the clutch fluid looks nasty so let's do that too". 

 

I opened up the bleeder and couldn't really pull any fluid, even though I had maybe 15 lbs of vacuum on it. I think it was sucking in some air around the threads of the bleeder but no fluid to speak of. I had also suctioned the master cylinder down to the low mark (but not empty) and refilled with a little fresh fluid. It sounded like it might be pulling fluid, but the bleeder tank didn't really fill, nor did the master cylinder level drop.

 

After doing this for a while, I noticed that I lost the clutch pedal (just goes down to the floor) so air got in there somewhere. I kept going with the bleeder tool but again not pulling anything.

 

Also, since the clutch stayed down, I pushed it in, opened the bleeder (got a little air and brake fluid shooting out) then closed it and the pulled the clutch pedal up, so I know there's air in there.

 

So now it's sitting in the garage and can't move... uggghhh.

[coolskaterkid]

I have bled clutch slaves by opening the reservoir  and then pumping the slave by hand pushing the air and fluid back into the reservoir.

[Stevo F]

Actually found the answer to my issue in a thread in another forum:

 

http://forums.anandtech.com/showthread.php?t=2112814

 

Basically, the shaft in the master cylinder was in too far, and was blocking the port in the master cylinder that would allow the trapped air and old fluid to bleed out. I loosened the nuts holding the master cylinder to the firewall and pulled the master cylinder about 3/8" away from the firewall. I hooked up my vacuum bleeder to the bleed valve on the slave cylinder and it bled out nicely. I bled the air along with about 4- 5 ounces of fluid out through the bleeder valve and had a good clutch pedal again.

 

I never woudl have thought that was the issue- if the guy in the thread hadn't mentioned his mechanic had done this when he worked on his '06 Outback, I'd still be out there messing with it.

[Fairtax4me]

If that's the case check the pushrod on the clutch pedal for an adjuster. The pushrod is adjusted to tight and not allowing the MC piston to return all the way. This can cause the slave cylinder to hold pressure on the clutch release fork and cause the clutch to slip.