MG Sports Cars

Graham is right, the TOB I'm using is a standard Ford as used with mustangs. I have whatever force is applied by the spring inside the slave -- I'm guessing it's more than 4lbs but wasn't "hard" to push the slave into position. Graham how did you adjust to get a good "preload" --- is it a matter of finding an appropriate spring to pull the fok back -- e.g. a spring from the fork to the bell housing that counter-acts some of the slave force?

Rob, the preload is obtained by lengthening the slave cylinder pushrod (adjustable) and thereby forcing the TOB forward into the diaphragm - 4 lbs isn't much and it's a bit of a guessing game. You shouldn't need a return spring - the clutch diaphragm is the basic return spring.
....hmmmmm, unless you opted for a pull type slave in which case you maybe left to spring pressure.......have you got a photo of your installation?

Also be aware that as the clutch disc wears the fingers of the pressure plate will move towards the TOB. Your slave has to account for this, otherwise you have to make periodic adjustments. Otherwise the clutch will start to slip as it wears. I always liked having a bit of play before the bearing touched the fingers. It allowed me to gage how fast the clutch was wearing by the decrease in the pedal free play.

JB



Edited 1 time(s). Last edit at 05/22/2010 02:46PM by BlownMGB-V8.

I haven't taken a picture of mine, but it's a push slave just like Joe Schafer's. It's also mounted similarly -- except I made the bracket that holds mine so the bleeder is at the top. It is mounted close to the bell housing & with the push rod going through it like his.



When I installed mine, the slave was about 2" away from the bell housing when the push rod started pushing on the fork. As I pushed the slave into position, the push rod pushed the piston in the slave back. Not sure if there is, but it felt like there was a spring between the slave piston & the back of the slave... it's that force that's holding the TOB against the fingers on the pressure plate.

It's hard to explain but did that make sense? Thoughts on that set-up?

I'll see if I can walk you through your clutch installation setup (assuming the system has been bled and all components in place.:
1) The first thing I'd do is to adjust your clutch pedal free play to about 1" by adjusting the pedal fork rod actuating the Master Cylinder. Pedal should travel 1" before the MC piston starts it's movement.
2) Manually push the clutch release fork as far forward so that the release bearing is just contacting the clutch fingers. Adjust the length of the slave cylinder pushrod to hold the fork at this position - now lengthen the slave pushrod slightly to achieve your 4 lb preload for the fingers.
With the Ford constant motion release bearing design, I don't see that you need a separate fork retraction spring - the clutch fingers will retract the fork/bearing and the slave cylinder piston (which also has benefit of a piston spring.)

EDIT: I have to (sheepishly) make a correction to this post, point 1) - astute MGB owners know that, while the brake MC pushrod is adjustable, the clutch MC pushrod is not - all the freeplay comes as a result of loose component tolerances. I blame my years working on HD trucks which have need for the afformentioned clutch pedal freeplay faux pas. Sorry Rob, et al.



Edited 1 time(s). Last edit at 05/24/2010 08:02PM by ex-tyke.

Graham, are you saying I don't really need a return spring on the throw-out arm? Now that I think about it stock MG doesn't use one and If I don't have to, I'm not gona. "P"



Edited 1 time(s). Last edit at 05/26/2010 02:32AM by pspeaks.

Paul, you shouldn't need a return spring if using a properly set up Ford constant motion release bearing.
In a typical vehicle clutch system that requires about a 1/8" clearance between the clutch fingers and the TOB, a return spring is required to ensure disengagement of the bearing from the fingers.

I'm using a NAPA stock 10.5 complete clutch kit and assume its a constant contact, but I don't really know for sure. I'll have to research a bit.