Clutch Slave Cylinder Question

[rehoward]

Okay, I am sure this sounds like a rookie question, but I am replacing the clutch slave cylinder on my 1993 K1500 pickup truck.
5 speed manual trans.

The new slave cylinder has a plastic nylon looking strap holding the piston and rod in the retracted position. Why is that there
and should it be removed before installation of the new slave cylinder? Or do I just install it complete with the strap still attached
and rely on the initial piston actuation to break it? It seems to be an odd arrangement to me.

Randy

 

[someotherguy]

Surprised yours didn't come with instructions that tell you to leave the strap in place during installation. It will break on its own once installed and used.

Richard

 

[rehoward]

That is what I thought, but wasn't really sure. No instructions at all. A decent Sachs unit and that should be a good OEM quality brand.

Randy

 

[someotherguy]

Wishing you the best of luck on the part choice. I had a slave cylinder pop a while back and chose the whole assembly, from Perfection Clutch. The slave and master in that set are made from aluminum instead of plastic. Considering when mine failed, the plastic had split open on the slave, it made the aluminum sound like a good choice.

However, installing an assembly "in place" is nearly impossible, at least on a 7.4/NV4500 combo. I tried multiple ways, beat myself up, then relented and knocked the roll pins out and installed it in pieces. Routing the line still sucked. Then, I had to bleed the system, which can be difficult - it seems to be notoriously difficult, but the procedure I followed was fairly easy, if not necessarily intuitive at first.

Following advice I'd found here on the forums which also was repeated in the factory service manual instructions, I had the slave loose under the truck and compressed the piston on it by hand in order to bleed the system. There's a process - I described it here in this post from my truck's build thread https://www.gmt400.com/threads/talk-me-into-or-out-of-it.60810/page-62#post-1423836

And by the way, jury is out on the quality of the Perfection Clutch setup - it's only been in my truck a couple hundred miles so far. It's still a project that isn't quite daily driver status.

Richard

 

[rehoward]

Thanks for the detailed info Richard. I have found that working on my truck clutch replacement has been a total PITA and has been
cursed with problems every step of the way. Not what I had expected from Chevy at all.

Randy

 

[JPVortex]

Hi!

Don’t be scared of bleeding the hydraulics. I installed every component separately when I manual swapped mine.

To bleed it all I did was first gravity bleed to get the initial air bubbles out. Then I reverse bleeded. I took the slave cylinder off the trans and then took the pushrod off and put a long 1/4” extension in its place. From there I pressed the slave cylinder down against the ground. I did this like 50 times and it bled it down perfect. By doing this you force fluid toward the master and all the air bubbles come out from the top of the master. Just be careful the master may overflow and be messy!

Good luck!

 

[rehoward]

While looking at my new slave cylinder and the old one, neither seems to have a conventional bleed fitting. Instead, they both have what seems to be a simple plug which looks like a setscrew. How are you supposed to bleed the air out? There seems to be no provision for connecting a hose to the bleed outlet which is what I usually do and then I usually attach a simple vacuum hand pump and jar to the bleed valve. It seems that repeatably during this project of mine, Chevy has cut corners at every opportunity and the results make it a much more difficult vehicle to service. Not like the old days of simple but effective design and user friendliness at all.

Randy

 

[someotherguy]

You do simply remove the plug and let it gravity bleed for a bit, then reinstall the plug and follow the procedure described above where you manually actuate the piston.

Others have tried various methods to bleed them and have become entirely frustrated with the situation; as I said they are (can be) notoriously difficult to bleed - if you try most of the expected methods, as opposed to the suggested one.

Richard

 

[rehoward]

So, remove the slave cylinder plug and let it gravity drain while keeping an eye on fluid level in the master cylinder reservoir so it
always has fluid.

Then, actuate the slave cylinder by hand several times to expel any trapped air up into the reservoir. Then install the the slave cylinder.
Did I get that right? I know cars, or thought I did, and this fussing around seems simple but a bit unusual without having a real bleed
valve to work with. Live and learn. How does the nylon strap thing already installed on the new slave cylinder figure into this or should
I just discard it?

What a hassle. I know this should be more simple than I am making it. I just want to get it done and do something else rather than endless
screwing around with my truck. I need to get a life. :-(

 

[someotherguy]

Leave the strap in place. Gravity bleed it for a while and yes, obv keep an eye on the fluid level so it doesn't run dry and you start all over.

Then the procedure for pumping the cylinder manually - from my linked post: "Unhook pushrod from clutch pedal. Remove master cylinder cap. Remove slave cylinder, slowly press the pushrod all the way in, then slowly release. Then, several short strokes about 5-10mm, while watching for bubbles in the reservoir. Add fluid as needed."

I didn't have a helper so I positioned my old d-cam on a magnetic tripod and recorded my efforts. First round looked like it was still making bubbles on the end of the short strokes so I repeated that process a second time.

Richard