Sorry for making two post in a row but the questions were quite different so I split them up.

I have a ZF5 that I just installed in my Bronco. I put a new LUK single mass flywheel kit on the 7.3 that included the flywheel, pilot bearing, clutch disk, pressure plate and throwout bearing.

I finally got to the point of installing the transmission and clutch hydraulics and was trying to get the clutch working to start my truck. However, getting the slave cylinder in (I reused the slave that was on the donor truck that was confirmed to work before removing) was nearly impossible.

After failing trying to compress the cylinder as hard as I could with my feet, I ended up using a ratchet strap to pull back the clutch fork which didn't really work. It was easier lifting the transmission with one of the straps than pulling back that fork. I also used a 2.5' pipe to pry and slave cylinder in place with the rod that pushes against the clutch fork. It finally went in.

The clutch pedal felt incredibly hard, but I remember it was very hard on the dual mass setup. Anyways, after pushing in the pedal, the slave cylinder burst.


Could there be something wrong I was doing with the hydraulic setup? I don't see why there was so much force to get the slave in, and it obviously seemed like too much since the cylinder burst. Could it just have been coincidence that it failed or maybe my install methods ruined it? Is the single mass flywheel setup about as easy to push in as a gasoline V8 clutch setup (like on the M5OD trannys that came in F150s/Broncos)?

Thanks for any help! Most of what I read said people pushed in the cylinders by hand, but I couldn't push in this cylinder wedging it against the frame and my feet while lying on the ground.

 

Sometimes when you remove the slave and let the rod extend all the way out, it won't go back in unless you remove the line from the slave and bench bleed it. Some do it and some don't. I made a tool that clamps to the slave and holds the rod in while the slave is removed from the trans. when you buy a new one they have a cup over the end of the rod with two plastic straps that clip in the bracket and holds the rod in. The installation instructions will tell you to step on the pedal and break the straps after the slave is installed, but if you put the slave in, then push on the fork to push the rod into the slave a little, you can unhook the straps without breaking them. That way you can hook them back up if you ever have to remove the slave again and they will hold the rod in, and you won't have this happen again.

 

When you get the new slave cylinder, take a look at one for an IDI, say 1991. It is a little bigger and seems to hold up well

 

Thanks for the replies! I wouldnt have thought about trying to reuse the plastic clip thats a good idea! Ill also look into getting an IDI slave.

Luckily I have an extra set of clutch hydraulics from the donor truck so I can swap the slave from the extra set. I tested to see if I could push this slave in by hand and I could. It actually wasnt too difficult to press in either. The other slave I popped wouldnt press in with me pushing as hard as I could with my feet so I assume it was somehow locked up.

 

What I found to be the best trick is something you have to do when you first buy the slave (or the whole hydraulic kit). When it's shipped, there's a strap that hooks to either side of the slave body and holds the slave rod back. The "official" instruction is to simply hit the pedal once after install, and that breaks that strap. What I do instead, I unhook the strap from the hooks on the slave body. That way, in the future, with the strap unbroken and the ends just hangin' out, I can re-hook the strap to the slave body before removing the slave, and re-installing it is waaaaaay easier. Just gotta remember to unhook the strap again.

As for pushing back a slave rod that's already extended, if it's still connected, you can always try loosening the cap on the master and that should make it easier to push back the slave rod.

 

Billy... Nothing special bud. Just a piece of stock round metal, with a hole in the middle. Was just out trying to find in the garage, but with the move in Jan, it seems I can't find jack-shiat anymore...