I bought a new clutch arm to slave cylinder push-rod as the one on the car looked sad
I went to fit it today to find my old one is about 1" longer than the new one and i can see where someone has extended it
Got me stuffed why
Anyone have an idea as to why
Bent clutch arm ball end?
Wrong Slave Cylinder?
Thanks
Marc

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1970 MK2 Cooper S

an old trick if the clutch arm is worn was to simply extend the push rod

Thanks

B

I think 1 inch is a bit extreme

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1970 MK2 Cooper S

The clutch arm ratio is about 5.5:1.
A small amount of wear at the ball end plus a small amount of wear on the thrust bearing carrier where the ball end fits translates into 5.5 times the required movement at the clutch slave cylinder end to compensate for the wear before the clutch actually starts to disengage.
So say 1/8" wear at the ball end becomes 11/16" extra movement at the slave cylinder end.
1" extra length isn't out of the realm of possibilities.
This plus the slave cylinder piston hitting the retaining circlip adds to the extra pushrod length required to give enough travel to the throw out bearing to disengage the clutch before the piston hits the circlip.
Heating and bending the clutch lever is a common fix along with removing the circlip.
With all this stuffing around, these days it's probably easier to replace the carrier and arm.
They don't cost much and getting the clutch cover/WOK off is the biggest issue.

Hope this helps
RonR

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68 build Mk1 Cooper S
72 Clubman GT project. Total restoration required

Beware the cheap bearing carrier or plunger is soft as butter. Measures HRC 2. Originals were about HRC 50.
They can wear out in 3 months use. I have fitted a hardened steel bush to a few.
Minispares sell a more expensive one, it is a bit harder but nowhere near 50.
There's also a race one available but it's way more expensive. Comes with a new HD arm.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Checked the arm today
I can see its bent at the ball end
Someone has also welded up the ball where the worn part was
So i need a new arm
So is mini spares the best arm to buy or is there better

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1970 MK2 Cooper S

All seem the same, except the race one which uses a race plunger. Useable as a pair only.

I bet the plunger is worn inside, should be a straight hole.

You can avoid arm need to bend by fitting a 5/8" flat washer behind the bearing.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

the plunger hole looks OK round and straight

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1970 MK2 Cooper S

They wear in tbe middle of the plunger hole

It will be worn if the arm is worn.

Replace it makes s real difference to the operation of the clutch the parts are in good nick

Also change the clevis pins

I also extend the clutch slave cylinder arm by 6mm if you have a clutch engagement issue.