Cross Reference for Mondial Clutch cylinder

Does anyone have a cross reference for a clutch cylinder for my 1981 Mondial? From another car, maybe a VW.

The clutch cylinder reservoir was empty today. I filled it with brake fluid and the clutch works fine.

Thanks
Charles

 

They are notorious. I have rebuilt mine twice. I was not able to find a cross reference, but I have to believe there is one. Remove it, hone it, replace the seal, you are good to go for a couple years. I didn't hone mine the first time and it ate a seal within a season. The second time I learned my lesson. The seal is expensive and I tried to source it elsewhere, even ordered an assortment of similar sizes from MCMaster Carr, but none were close enough. It's the same cylinder on a Boxer, but that doesn't really help.

Birdman

 

I check the rear cylinder and it is leaking. Is this the one you rebuilt?

I sent you a PM.
thanks
Charles

 

Yes, for some reason the slave (rear) cylinder on these things wear out faster than any of the other hydraulics on the car.

Hey Judge, ya still got my funky seal tool? We might have another person needing to borrow it.

Birdman

 

I think the slave cylinder is made by Bendix IIRC and I'm betting we can track down one that is similar enough to fit.

Birdman

 

The original cylinder can easily be rebuilt by boring it out & installing a sleeve. Would be as good as new.

Birdman, do you still have that cylinder you honed out? Want me to rebuild it in my copious spare time?

 

I need to take mine out and rebuild it. Can any one chime in with details of their rebuild? Pls?

 

Verell, the one we honed is the only one I have and it's back in the car. So far, no leaks and holding up well.

BACKGROUND: The first time I "rebuilt" mine I didn't hone it, just replaced the seal. There was a bit of corrosion in the bore (more than I realized) and it "ate" the new seal promptly (a driving season). So next time I pulled it out, Verell and I honed it and I replaced the seal again. The seal is a total ripoff, about $65 IIRC for a plain rubber cup seal that you would get from McMaster Carr for about $0.25. Unfortunately, it is a non-standard size that I was not able to source ANYWHERE except Ferrari. And believe me I tried. I even took the number stamped on it from the OEM manufacturer and hunted around on the internet for any hint of a lead. Nothing. I think you would have better luck sourcing the entire slave cylinder. I'm going to bet that this is a standard shelf item that was used on many cars of different brands. I have a lead that says it was made by Bendix, but I have no proof of that.

The trick is that replacing the seal involves stretching it over a VERY large piston to get it on the groove where it sits. You can heat the seal in boiling water to make it more flexible, but there is a VERY good chance you will tear the seal putting it on. After I tore my first $65 seal, I realized that you can't physically stretch it enough by hand to get it on there without damaging it. So I fired up my lathe and made a little conical tool to stretch the seal very uniformly. You heat the piston, the seal and the tool in boiling water, then use a vise to hold them together and quickly pull the seal over the tool and onto the piston with some brake fluid as lube. Works great. So my second $65 seal went in nicely. (And wore out a year later!) I loaned the tool to Judge4Re and he used it to rebuild his, and he is now returning it to me. I am happy to loan it to any fchatter that needs it.

But we should really find a generic replacement for this stupid cylinder assemble. I'll bet it's a $50 part at a Napa if we had a part number.

Birdman

 

The tool you use to hone it is an inexpensive brake cylinder hone that goes on a drill like this one:

http://www.opentip.com/products/Brake_Cylinder_HoneInterior_AccessoriesAutomotive-548738.html

Quite simple.

1. Remove the piston from the cylinder while on the car (because you can use the pressure of the hydraulics to pop it out, but go slow because it can shoot across the room!) Taking it apart simply involves removing the clutch linkage (a cotter pin, a few other parts, very obvious), removing the rubber boot, and then use circlip pliers to remove the circlip that prevents the piston from coming out. Make note that a spring will also come out from inside.
2. Remove the cylinder from the car. (Two bolts to remove, and the hydraulic line...easy.)
3. Hone the cylinder with the brake hone. Get one that can go as small as 3/4" because that's about how large the bore is. Hone it until it's smooth and shiny inside. You would be surprised how much you can hone it before all the imperfections are gone.
4. Clean it out to remove all the metal sludge from honing. Lube it up with brake fluid.
5. Remove the old seal from the piston (just grab it with needlenosed pliers and yank it off. It will tear, no biggie, it's toast anyway.) Make note of the right orientation of which way the "cup" on the seal faces (towards the pressure) before you remove it.
6. Use my funky tool to re-install the new seal in the right orientation with proper heat and lube.
7. Put the thing back together. Don't forget the spring first! You can completely re-assemble on the bench including the circlip. You may find that the seal doesn't want to go into the cylinder because it gets hung up on the edge. Just lube the whole thing with brake fluid and push it in nice and square, it will pop in.
8. Install the whole unit back on the car, hook up the hydraulics, hook up the clutch linkage, bleed it, you're done. No adjustment necessary, it's self adjusting.

A power bleeder makes bleeding a lot easier.

This is a very easy job. If you have all the parts (i.e. the hone, the seal and the seal installation tool), you can do it in a couple hours. The location of the cylinder is a little inconvenient if you don't have the car on a lift. But it can be done. (I did mine once on the lift and once on jacks because the 308 was on the lift!)

Birdman

 

Thanks Birdman!

I have the whole thing almost out of the car right now. I am having problems with the pin that holds the piston to the clutch lincage thingy. I will give it another try tomorrow... maybe.