7 replies to this topic

[1964coopers]

Hi. Having a hard time figuring this one out. The car came with a 5 1/2” slave cylinder pin length. Because it was bent I bought another assuming it would be the same length but it’s nearly 2 inches shorter. With the new pin installed, the clutch would have too much free play. As it is with the 5 1/2” pin the clutch seems to work ok but hasn’t been driven yet. However, it’s so long the arm doesn’t rest on the bolt stop. I didn’t try to adjust the nuts because from other instructions I have found they show about the same amount of threads sticking out of the end as mine do. Not being too familiar with these clutches I cannot say if the housing has been modified or why. The diaphragm/ pressure plate appears to be stock and it has an AP racing disk. Anyone seen a setup like this before and know why it may have been set up this way? This is a full race car with Jack Knight transmission. Thanks for the help.

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Edited by 1964coopers, 22 August 2024 - 02:45 AM.

[timmy850]

Needing a long slave cylinder pushrod, and looking at the angle of the clutch arm it appears something is worn beyond the factory spec.

 

I'd check:

The clevis pin at the bottom of the clutch arm, plus the hole in the flywheel cover and clutch arm

Check the ball on the clutch arm where it meets the throw out bearing plunger. 

 

Due to the large leverage ratio of the clutch arm, any small amounts of wear at the small end add up to a big difference at the slave end. 

 

Ideally you want the throw out bearing as close as possible to the clutch diaphragm at rest as long as it isn't touching. This means the pedal travel will immediately touch the diaphragm and actuate the clutch. If the system is too worn the slave will run out of travel 

[1964coopers]

Pulled the arm, for sure the ball is worn and will be replaced. Curious however about the end play in the plunger. It moves in and out about 8mm freely at rest. Without pulling the cover I seem to remember the bearing looking ok but maybe this is an indication it is not? Not sure how much free play there should be with no arm or slaved hooked up to the plunger. I guess it possible the clutch height is incorrect but I would assume it worked at some point. Maybe there is a race setup that’s different than factory?

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[Spider]

I don't have the figures to hand, but there was 2 different (pre-verto) pushrods used in production. The early ones, were typically found with Spring Clutches and wet Primary Gears there were around 3/8" shorter than the later types.

The free play you see there in the plunger (without the arm fitted) is about what I'd expect to see, though it does appear the Over-through Nuts might be set a bit close to the cover. Once you have your new parts fitted (and I'd suggest a new plunger as the hole in that will likely be worn), back the nuts of, then lever the arm out all the way until its stops, check there is clearance between the over-throw nuts and the cover, then wind down the flanged nut until it touches the cover, le the arm go, then wind that nut on a further 1/4 to 1/3 of a turn, hold it there, then lock it up with the lock nut.

[nicklouse]

Pulled the arm, for sure the ball is worn and will be replaced. Curious however about the end play in the plunger. It moves in and out about 8mm freely at rest. Without pulling the cover I seem to remember the bearing looking ok but maybe this is an indication it is not? Not sure how much free play there should be with no arm or slaved hooked up to the plunger. I guess it possible the clutch height is incorrect but I would assume it worked at some point. Maybe there is a race setup that’s different than factory?

It does not matter. There has to be movement. And you set it as per the info in your workshop manual, as covered above by spider).

 

but yes get the plunger changed. And all the clevis pins and check the hole in the cover the clevis pin goes into for wear and fatigue as the do break off. 
 

ps the original pin was a fix that someone did. Not an original part.

[GraemeC]

It’s probably just the photo, but the arm looks bent (and bent in the opposite way to what they usually are).

I’d replace all wearing parts and start again:
Push rod
Plunger
Arm
2x clevis pins

Check the clevis pin hole in the wok for wear too. I have managed to save one of these in the past with DU bushes

Edited by GraemeC, 22 August 2024 - 08:17 AM.

[Lplus]

It’s probably just the photo, but the arm looks bent (and bent in the opposite way to what they usually are.

I’d replace all wearing parts and start again:
Push rod
Plunger
Arm
2x clevis pins

Check the clevis pin hole in the wok for wear too. I have managed to save one of these in the past with DU bushes

This - the lever appears to have been bent away from the cylinder.  It is not one of the thicker levers - those bend the ball first.

[1964coopers]

Thank you for all the input and expertise. New parts in route, hope it fixes the issue.