I spent the weekend with my father in law, working on replacing the hydraulic clutch system in my '94 90 Quattro Sport. We're looking for some pro tips on replacing the clutch slave cylinder after having spent the better part of yesterday on that single step.

A little background: the cylinder has to be almost completely compressed in order to be secured to its mount on the transmission - a single ~8mm bolt. With the slave sitting in my lap, it takes about as much force as I can muster to compress it fully. With my arms snaked through the undercarriage, I can get it to within about a half-inch of its necessary compression. Resistance at that point feels more like a solid block of metal rather than a spring - and I am just certain that, even if I could get it compressed the rest of the way, I wouldn't be able to hold it there long enough to get the bolt in place.

The bentley manual for the car doesn't offer any advice, except to say that you "might" want to use a bolt with a tapered tip - presumably so that you can "catch" the bolt hole without letting go of the slave. We didn't have that bolt but I'm going to try to find it before I reattempt. It's not going to be enough, though.

I'm no expert mechanic, but the FIL is pretty experienced with similar cars. After about six hours taking turns with our arms biceeps-deep in the undercarriage, we were no closer to getting that cylinder in place.

I'm sure there's somebody here that's gotten this job done. Can you tell us how you did it? Short of just finding somebody significantly stronger than either of us (but with arms skinny enough to fit up where they need to) I'm just out of ideas.

Sorry for the wall-of-text post. All help appreciated.

 

I'm going to be your new favorite person.

I struggled MIGHTILY with the replacement on my 93 90q last year and then found this tip when I did my S6 a month or two ago....

http://forums.quattroworld.com/s4s6/msgs/41316.phtmll

What I think this doesn't tell you is that it is even easier to compress the piston if you suck some brake fluid into the slave before you cap it off. I you do that it will stay compressed better and just pops right in there,

Enjoy

 

Also, once you get it in place the bolt holes just line right up.

 

grillage ~

First, thank you so much for dropping in to help out.

As for the link - interesting. I found the same page myself today - of course, I missed it all weekend when we were actually working on this. It has renewed my optimism, but mitigated somewhat. Here's the deal...

While we were working on it, my FIL had the same thought as deephouse, but we had no access to a custom part (the blue stopper from his pictures), so he had the idea to buy a brake line with the proper fitting, cut it, crimp it over, and seal it shut. We did that, installed it, then filled the cylinder with brake fluid through the bleeder valve opening before sealing the whole thing. Then we opened the valve slightly, compressed the cylinder (with a slight loss of Dot4 as expected), and resealed.

The end result? No change. The piston still expanded, and the resistance to compression did not feel any different.

Two possibilities:
* As I mentioned, the model may just be different, with the spring function separate from the hydraulic function
* It is potentially possible that our makeshift "stopper" is not performing its function

I felt confident yesterday that it was working as intended, but having now two separate reports of that idea working in other cars, I'm wondering how likely it is that the design would be so significantly different from mine. I will check this (maybe a little soapy-water test) tonight and report back.