I pulled the cap and found a bunch of fluid (condensation?) on top of the rubber cup.
Had a friend pump the pedal while I looked for firewall flex and travel at the arm.

Didn't do a thing, but it seems ok today.?

Hope yours gets better with use!

 

If the slave cylinder has a bleeder screw. I would reverse bleed it.

 

The only bleeder on the plastic slaves is just a hole with a cross drilled allen set screw.

I also have a metal AP brand slave in a box somewhere. That one may have a real bleeder.

 

The lack of a bleeder on the slave is, in my opinion, a major problem. I don't know about anyone else, but I prefer to flush the fluid in both the hydraulic clutch and brakes every 1-2 years. Brake fluid, by design, absorbs water. The water then causes the metal bits in the system to rust and pit, which accelerates the wear on the rubber bits. Also, as the fluid absorbs water, it has less lubrication properties for those rubber bits.
Getting the air out of the system is also much harder, thanks to the lack of a bleeder.
Yes, I will admit that clutches are way harder to bleed than brakes, which is why I built my own pressure bleeder. Makes the job MUCH easier, especially since all my vehicles that have hydraulic clutches have a bleeder on the slave........

 

One more thing to add to your list of reasons to flush brake fluid, Water is 1 part oxygen!

-Enjoy
fh : )_~

 

True, but I did *kinda* touch on that when I mentioned rust (AKA iron oxide).

 

On the notes above, it's better to put DOT 3 in than DOT 4 as DOT 4 is even more willing to take water and should be changed more frequently.

On my corvette, you can "flush" the fluid by syringing the reservoir empty, filling it with clean fluid, pumping the pedal up and again. Does not completely flush the system like bleeding through to a color change, but as a semi-annual preemptive service could probably negate the need to flush the clutch system until the components need to be replaced.

 

Just curious if this is a slave cylinder issue or a clutch master cylinder issue.

 

I don't think I follow your question.

Generally speaking, the hydraulic setup on these trucks is infuriating.

The biggest issue is that there's no (true) bleeder screw on the slave like on a typical vehicle - and it gets almost impossible to get all the air out.

 

Well, I think I found my problem.
The sintered bronze bushing I had installed years ago cracked and there was too much free play at the M/C pushrod.
I just went to the hardware and got another 3/8->1/2" shouldered bushing, a 1/2 ->3/4" bronze washer and a 1/2" axle push nut.
After removing the remnants of the old one it's obvious I had filed down the belcrank stud to fit within this bushing.
Once the Prosteel epoxy sets up I'll re-install the Master Cylinder pushrod and see how the action is.

EDIT: It seems to have worked. There's no grinding or drag.

If I had a real bleeder nipple I would back bleed the system. Willing to bet that there would be no issue with the hydraulics then.

The real problem with this era of trucks is that there so many modes of failure.

Firewall flex & tearing.
Pushrod bushing (plastic clip) failure.
Pushrod adjustment.
Diecast Zamak pedal support trunnion wear.
The belcrank arm on the end of the cross shaft can twist it's splines.
The usual leaking hydraulic seals in the master or slave cylinder.
No way to positively bleed the system.
For diesels and big blocks the throw out arm can wear, or warp.
And for small blocks the slave is entirely internal to the bell housing.

 

Drill out the bellcrank pin cut off the rod end on the pushrod, thread it and use a heim joint, problem solved for ever!

-Enjoy
fh : )_~

 

The Heim joint would need to be proud of the belcrank by 1/2" or so to maintain some kind of alignment with the M/C bore.

 

Didn't on mine, aligns perf., works perf.!

$3.00 for the heim, It'll never fail in my lifetime.

-Enjoy
fh : )_~

 

The procedure for bleeding the system as found in the factory shop manual is to either fill the slave, then fill the master with the line unhooked until you have clear fluid running out with no air and then make the connection to the slave, or to install the master and slave as a unit, fill it up, and manually compress the slave cyl by pushing the clutch fork towards the front of the truck about a dozen times.
Only ever used the second method, but, it always works fine for me.

 

I hate to pull up a dead thread, but thought I'd repost for anyone searching in the archives.

Thanks to everyone here for all the advice, what I ULTIMATELY ended up doing was this:

1. Got a new MC / SC / line.
2. Hooked the new line up to the new MC, filled the MC and put the other end of the line in a jar of brake fluid.
3. With the reservoir on the MC open and the nose pointed down, actuated the push rod of the MC multiple times until I was satisfied there was no air bleeding back in to the reservoir or out into the jar.
4. Filled the slave cylinder with fluid (this takes a while, the sucker really holds quite a bit of brake fluid) until I could see fluid in the port. (It's also messy.)
5. Connected the slave cylinder hose.
6. Tilted the slave cylinder so that its nose was down and retracted the pushrod by pushing it against a wood block on the ground VERY slowly. Had a helper watch the fluid level in the master cylinder. Every time an air bubble came out, the master cylinder would pretty much puke. Keep the fluid level up.
7. Once my helper was satisfied that no more air was coming into the master cylinder reservoir, I pushed the slave cylinder down and reclipped the shipping band so it would stay retracted for easy install.
8. Install the assembly on the car, making sure there's minimal freeplay in the master cylinder pushrod.

At this point, I checked the pedal. No hangup - ANYWHERE in the travel. Started the motor and ran through the gears at an idle (1 - 2 - 3 - 4 -R). Did this five or six times, making sure to let the clutch out in neutral now and then to verify.

Road test was GREAT, clutch engagement was very far off the floor. Didn't have to "drive it off" at all!