Stiff clutch pedal

[Lotsats]

No Lotus Elan here, but l have recently finished a very thorough restoration of a 1966 Lotus Super 7. I also have two other 7’s. I installed a somewhat modified Lotus Twincam in the car. The engine markings indicate it came from a Cortina Lotus. The clutch master cylinder is 5/8” diameter and the slave is (I recall, but need to check this) 3/4”. The clutch pressure plate and disk came from the boxes of old new parts included with the car (disassembled since 1988) which was in pieces when purchased, so I used them. They appeared to be normal type components, and there was no indication they were of a competition type.The pedal action is smooth, but very heavy. I first drove one of these in1965 and expected a heavy pedal pressure, but not this heavy. I just ordered a Wilwood 1/2” master cylinder with remote reservoir. It will bolt right up. This is the only master I could find with a bore that small. The remote reservoir will be beneficial as I used a Triumph Spitfire dual brake master for safety reasons and there is a clearance issue with it’s reservoir and the fill cap for the clutch master. If my math is correct, the smaller bore master moves 36% less fluid for a given about of travel, so the pedal pressure will, hopefully, drop by about the same amount. I think there is enough extra pedal travel distance to allow for the additional movement needed. If I haven’t used faulty logic, this might be a way of improving the heavy pedal issue. Of course, I’m human, so maybe this won’t work, and would appreciate any feedback. Thanks!

[jcocking]

This posts was split from another post

[gjz30075]

On an Elan, the master is 5/8" and the slave is 7/8". A very similar actuation method as the 7. Going
to a 1/2" master will probably accomplish the same as going to the 7/8" slave instead

[RichardHawkins]

Lotsats,

You are now 59 years older than you were in 1965, of course the clutch is heavier! Stairs are steeper, and things I squirreled away in the garage are now too heavy to move. I never thought this would happen, but it has!

Hope this helps,

Richard Hawkins

[alan.barker]

Fit the correct 7/8" dia slave cylinder and see what you think.
Alan

[SENC]

3/4" slave cylinder is correct (or at least original) in the Seven S2. Depending on which resource you look at, the master should be 5/8 or 3/4 (Lotus parts list says 5/8, Girling parts books for S2 says 3/4, DBE catalogue says 3/4).

No reason not to try a smaller bore master or larger bore slave for less pedal pressure, as long as the trade-off stroke length works.

[MACCA.GLM]

Don't know what clutch you have but I have a genuine Borg and Beck with original clutch and slave cylinders. It is very light and perfect for standard sprint. No problem for my 67 year old milk bottles
Regards
G