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940/120 clutch slave compatibility

Sparkles

New member
Joined
Jun 29, 2017
I've got an M90 from a '97 940 in a '68 Amazon and I'm getting around to plumbing the clutch. I don't have the 940 clutch master cylinder available, the standard 120 master is fitted. I do have the slave from the 940 AND the 120.

Before I try to solve this with my ghetto burette I thought I'd see if anyone knows what the compatibility between the cylinders is like, or just the easiest way to hose this up.
 
That's good knowledge, thanks.

I don't suppose you know where I could find out the thread types and sizes of the different hose ends involved do you?

It would be good to figure out if there's an adapter to go between the standard 120 hard fitting on the inner wing and the little pigtail-flexi hose that's on the 940 slave cylinder. Better to keep it standard than get custom hoses made up.

Thanks.
 
The 120 hard line is 7/16"-20 male inverted flare so you need a female hose end. The 940 slave uses a M12-1.0 bubble flare fitting which will be difficult to source but a banjo style AN adapter or straight adapter with a crush washer can also be used.

https://www.ebay.com/itm/1-Steel-Banjo-Bolt-Fittings-M12-x-1-0-Metric-12mm-to-4AN-4-AN4/112321763842?hash=item1a26e61a02:g:9UMAAOSwdIFX1ziF

https://www.ebay.com/itm/4AN-4-AN-4-to-M12x1-0mm-12mm-1-0mm-Straight-Fitting-Adapter-Fuel-Oil-Gas-Water/323741867087?hash=item4b6084dc4f:g:eek:LcAAOSwknJX0hiX
 
I used the stock 122 clutch master cylinder and a 740 slave cylinder and they work fine together with a stiffer pressure plate. As Ian mentioned, you need to have a custom hose made up to connect the hard line out of the master to the slave. I did it his way - female fitting on one end and a banjo on the other.
 
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All the Chinabay AN parts finally arrived and I put this hose together. The straight M12 fitting for the slave cylinder didn't have much of a shoulder for a crush washer but it did kind of neck down after the thread so I tried it with a 10mm x 1.5mm o-ring and it's working.

I used a hardline to AN adapter so I could snip the flare off the stock pipe and go straight to AN. Made the mistake of getting a female swivel adapter version, so I got a male union to join it to the hose end. It's an extra joint to leak but it does allow the original hose locking washer to be reused as a bonus.

Looks like a pretty decent amount of piston travel on the gearbox end. Thanks again for the help.
 
Now that I think about it, maybe I didn't use a banjo on my slave cylinder. I'd go look but I don't feel like lying on the ground right now. I'll be pushing the car back into the garage soon enough.
 
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