Clutch bleeding method

[OLDCHEV4X4]

Whats the secret to bleeding the clutch.
I put a new slave on my 86 GMC cause it was leaking when pushed. Opened up the bleeder and filled the reservoir. When fluid came out i closed it. No pedal. I tryed pushing the pedal severl times. nothing.
I opened up the bleeder again and let the fluid flow. Nothing.

[MotorHead Lon]

Your best bet is to get a vacume pump, normally used to bleed the brakes. Fill the resivor and attach the pump to the bleeder valve and pump until you get fluid and no air. On my 90 I worked on bleeding the clutch over 3 nights, before I got the pump. Then it took about an hour.

[swb85]

^^^^Agreed. Go get a $30 hand vac pump from your local parts house. I don't even touch hydro clutch systems without one. You've got an air bubble in the master most likely, only way to purge it is with a vac pump.

[OLDCHEV4X4]

Ok, i got a mighty vac. I hooked it up to the bleeder screw on the slave. I topped off the reservoir. I opened the screw and pumped the mighty vac about 50 times.
Then i would close the bleeder and top off the reservoir again, making sure that it never went dry. I did this about 10 times. I had to empty the reservoir on the might vac twice.
I worked the clutch about 60 times.
The clutch is finally working, but it grabs as soon as the pedal moves off the floor. This is not how the clutch worked before.
I'm gonna try and bleed it like brakes tomorrow when i have some help.
Anybody have a experience like this?

[OLDCHEV4X4]

Well i had pedal when me and Dad started, but barely.
Dad would push and hold the pedal down. I would crack the bleeder, fluid would come out, close bleeder, Dad would lift pedal. Check reservoir. Repeat.
Did that 6 or 7 times.
Now i have no pedal. It got worse.
So i retightened my line fittings, checked my reservoir line fittings and went back to the mighty vac.
So after another pint of fluid i'm back to where i was. The clutch grabs right off the floor mat.
Any sugestions???

[asphaltburner]

Yo! Trapped air is probably the problem in each case.
Whenever hydraulic masters or slaves are changed, they should be bench bled since it's so hard to do it using the piston in the master while bleeding the system. Small orifices, large air reservoirs, and surface tension create the problem. I just recently responded to a similar post about a brake master cylinder.
It is possible to use a syringe and hypodermic needle to inject brake fliud through the small orifice to eliminate an air pocket, but usually the cylinder needs to be removed, placed in a bench vise, and bench bled. Some cylinders come with bench bleeding instructions,...but certainly NOT all! Todd.

[OLDCHEV4X4]

Could you explain this syringe method with more detail. Where do i inject?
The instructions said nothing about bench bleeding. Otherwise I would have done it.

[asphaltburner]

Yo!
Checked out my literature. Your clutch slave must be removed from it's mount, angled at a 45 degree angle with the bleeder valve up (attach hose and submerge the end in a container of brake fluid). Push the clutch pedal to the floor and open the bleeder valve. Close when no more fluid flows from the hose and release the pedal. Repeat, keeping the reservoir full. When you get a solid column of fluid from the hose, you can re-install the slave.
Only masters can have air sucked from, and fluid injected into, the small orifices at the bottom of the reservoirs,...and bench bleeding is best.
Sorry I mislead you about the slaves,...stupid of me, so I've slapped myself a good one!
Sure hope this gets you on the road again! Todd.

[us111]

never tried it but have heard of taking a fluid pump
attaching it to the BLEEDER ,remove cap slowy pump
fluid thru the bleeder,supposedly it will burb the air out thru the top.