Spitfire Clutch fork and hydraulic cylinders

[Trevor Triumph]

Is it possible to install the clutch fork incorrectly? Installed new clutch MC and SC. Can not shift into any gear.

Also, are the 3/4" and 7/8" slave cylinders interchangable? I have the single rail transmission, but apparently the factory changed the slave cylinder sometime during production. The number in the various catalogs aren't helpful; they just say "from previous year." I'd really like to drive the car this spring...
T.T.

 

[bobhustead]

The volume of hydraulic fluid moved by a master cylinder is exactly the same as is moved within the slave. If you increase the diameter of a slave piston, that piston is going to move less distance with the same master. Conversely, if you increase the diameter of the master, the same slave is going to move more distance. Although that 1/8 inch diameter change seems small, 7/16 x 7/16 x Pi = . 6013, while 3/8/x 3/8 x Pi =.4117. Big difference in area and therefore volume. It might still "work" in some systems depending on the geometry of the of the levers pushing the throwout bearing. But I wouldn't bet on it. If you have retained your original cross shaft and fork, it is not likely that the fork could be installed wrong. If you have replaced either, there could be a drilling problem in the manufacture that throws the above mentioned geometry into unusable territory.
Bob

 

[sp53]

My wife had a 1971 spitfire back in the seventies. Anyway I put a clutch in it and could not get it to shift. There was no adjustment on the slave or master, so I talked to a shop and their comment was the clutch disc is too thick. They said that they put a little piece of something on the end of the slave for about the first 25 miles or something and the newness of the clutch would wear down quickly and things would be fine. Or I believe they said try and drive it, I think by push starting in gear or something then pump the clutch a couple of times to shift and the newness would wear off. I know this sounds crazy, but something like that happened. Hopefully someone else has a better solution, but we did get the car going. maybe make a longer rod and see what happens. I think it was a small steal rod

Steve

 

[Trevor Triumph]

I don't remember how many miles and years are on the clutch components. I suppose it is possible that the clutch parts are worn. One time when I was aware of a failing clutch, the car would creep forward or backward the pedal pushed to the floor. I didn't notice this behavior this time. I should get back at the Spitfire this week. i had the get the Herald to run - varnish in the fuel tank. The car was nmot driven afo about a year.