clutch pedal

[Dean]

just a quick question

did clutch pedals ever change there leverage angle like brake pedals did compared to early drum pedal to later 8.4" disc pedal ????

we all know changing to the later 8.4" brake pedal gives you a better brake pedal
but is it the same with clutch pedals.????

i have not yet measured my total clutch movement, but i am finding that i don't feel like its getting enough throw. it goes in to gear but i basically have to have the release bearing touching the diaphragm to get it to release the clutch when pressed,
i know its not good to run it like that, so lucky its not on the road yet

everything has been checked, no air, clevers pins are new, arm and plunger are good ,new master, slave and braided hose etc etc

i will remove the gasket from under my master cylinder which will help a tiny bit with travel,

but as a last resort i may remove my clutch arm weld up the clevers pin hole and re drill it a few mm higher to get a bit move travel, which will lift the pedal up to give more throw, but i will have to make sure it does not bottom out my slave and over throw my clutch.

if a later 80's clutch pedal has a better throw angle i will swap it over, did with my brake pedal.

it was meant to be a quick question, but i always end up throwing different ideas in,!!!!!!

[1071 S]

".....but i basically have to have the release bearing touching the diaphragm to get it to release the clutch when pressed,
i know its not good to run it like that, so lucky its not on the road yet.."

I wouldn't worry about this. One trick to getting the last pooftenth of travel is to remove the clutch arm return spring. A few years ago I did this on the recommendation of one of our local gurus. I have not had any problems since. AIUI the factory removed the spring in later years. The other benefit is a totally self adjusting clutch.

"..i will remove the gasket from under my master cylinder.."

However, I would be very careful with this. I know several people who have had problems with the brake cylinder not returning due to the return port being still covered if the cylinder is sitting too low. On my car, both cylinders share the same gasket .... and I can't remember where the clutch return port is .....

Years ago when I had a similar issue (because of a non standard flywheel/backplate) I had the slave cylinder resleeved slightly undersize. Double benefits stainless sleeve makes the slave virtually indestructible and more travel... The seals came from a Holden Torana (nee Vauxhall Viva)

"..i have not yet measured my total clutch movement.."

IIRC the travel at the top of the clutch arm is 15/16th of an inch.

Cheers, Ian

[JohnA]

Try a new clutch arm it's possibly bent between the ball and the pivot it only needs to be a few thou and it won't clear, it's usually caused by pressing the clutch with the clutch stop nut touching the clutch housing before the pedal touches the floor. Also check that the ball hasn't got a flat on it. Failing this Pad has a quick method of rectifying the problem but it does require experience and a precision tool

[Dean]

ok

thanks for your replys

i have the clutch stops un done so they are out the way, i will try another arm but all the ones i have are used so might not get any where,

i did hear that pads special cool may of been a persuader ha ha.

i have a gasket under the plate/tray, and a gasket under each master cylinder at the top, so i don't have to remove both, i will try it as my foot is hard on the floor to get my clutch to release.

what about one of MS or MED heavy duty clutch arm things???

also my main question was, are clutch arm ages different for early to later cars

[rich@minispares.com]

the later clutch pedals do have a different ratio to the early ones

I recently fitted a later clutch and brake into the 'er' and it made the clutch nicer, it lifts the pedal higher up off the floor

[Dean]

thanks rich just what i needed to hear, i already have a later brake pedal, so now i need to look for a later clutch pedal and swap them over. and see how much it changes, if i can have the pedal thats little bit higher, it will help with the amount of throw i can get.

thanks dean

[goff]

the later clutch pedals do have a different ratio to the early ones

I recently fitted a later clutch and brake into the 'er' and it made the clutch nicer, it lifts the pedal higher up off the floor

Dean I got the oxy/ acet on mine , its now the same height as the S brake pedal , obvious you are taking it of then just warm it up and bend it, mine was hitting the floor carpet , hardly any travel so it got the above treatment, though mines a plastic pig.
Goff

[Dean]

goff, sound like i have the same problem as you had, if i can't find a later pedal quickly i will get a heat torch on it and give it a bit of a bend,

[pad4]

hmm - sounds familiar , i had a new arm and a new plunger in (as well as new master cylinder, slave cylinder, clutch , kitchen sink etc)

my thought - the arm isnt correctly machined so out came the micro adjustment tool and we whalloped the ball on the bottom only a midges dick and its perfect now - absolutly perfect

Pad

[Dean]

well if all else fails i think i will give it ago.

i did change the arm another usd one i had laying around , its a little bit better, but i picking up a later clutch pedal tomorrow so i take out the one i have and check the angle difference.

[Nevsmini]

This is a pet hate of mine with mk1 minis especially if the carpet is thick (as it is with coachbuilt minis). Did anyone ever use a modified S master cylinder as a clutch cylinder or is it possible to get a smaller Dia slave cylinder?

[Dean]

i think the trick back then would be to heat and bend the pedal, thats the source of the problem.
playing around with the clutch arm, stop, and that big nut stop will help, but in the end its the ratio of the pedal stopping the throw.

sleeving the slave is a good idea, but only if you have the skills and tooling to do so,
i did not want to start to modify any of the parts under the bonnet as at any time they need replacing they would also need modify to fit as well

so i can see modifying the pedal to be the best way.

but we will see.

[1071 S]

"....i did change the arm another usd one i had laying around , its a little bit better, .."

If you follow the logic of the clutch operation you will see that this doesn't matter....

The position of the bottom end is determined by the plunger length/bearing thickness. The position of the top is immaterial as it floats along with the slave piston. As long as there's room at both ends of the slave bore the exact position doesn't matter.

The only reason to bend the clutch arm is if the piston is bottoming on the slave c clip when the clutch is fully disengaged.... and, if it is, the best solution is to simply extend the length of the slave to clutch arm rod (check the position of the piston by peeling back the slave rubber cap and have someone push the pedal to the floor.)

The only way to get extra travel is to get more pedal travel or a different ratio between master and slave cylinder diameter. Noting that if all the linkages are to spec - and you have standard clutch parts - then the factory designed set up should be perfect.

Cheers, Ian

[Nevsmini]

Dean if you lengthen the rod between the clutch cylinder and pedal it should do the same thing as bending the pedal.

[JohnA]

If the clutch pedal is pressed with the stop nut just touching the clutch casing the arm will bend changing the pivot angle, the arm bends between the ball and the pivot(clevis pin),its weakest point. This can be checked by putting the arm alongside a new arm with both clevis pins fitted and the noting position of thrust face the ball. If it is low the clutch will not clear even if you pack out the slave cylinder, I think Pad could be right with his point the some of the repro arm may not be machined accurately I had to tweak a new arm on guys Cooper S on the LeJog at the side of the road. To change the angle open a vice so the outer face of the ball is sitting on the top of the jaw and the long side of the arm is sat on the other, making sure that the clevis pin hole is central the same distance between the ball,the clevis pin and arm. Apply downward pressure to change the angle. I learnt to do this years ago when I was an apprentice and I had bent a new arm by pressing the clutch against the stops and didn't want to tell the foreman and finish up getting balls greased !! I have used the method many times over the last 50yrs and it does work doesn't it Pad

[Dean]

well after getting hold of another pedal box and removing the clutch pedal from it, and also from my car, i found them both to be the same angle, bollocks

so i ended up adjusting my original pedal, i don't have access to a oxy torch so i cut a slot in the arm near the top and bent it open bit , then welded it back up.

it cam out really well, and now i have a really nice clutch pedal.

its nearly up to the same height as my brake pedal which is also a later disc brake pedal,
it does not bottom out my slave,
i can easy have the 0.020" gap on the stop, and have a bite point thats not on the floor
before my bit point was when the pedal was flat on the floor, now its a lot better and like any normal car, and now goes in and out of gear smoother, it never crunched, but was a bit notchy

so glad i did it, its made my car so much nicer to drive when you don't have to worry about having clutch pedal pressed hard on the floor to get it to release the clutch, and also now have a 0.020" gap so my release bearing it not in contact with my diaphragm all the time

dean