4 speed clutch release bearing on 3 speed gearbox

[Mark R]

I remember an article years ago about how to fit a 4 speed release bearing to a 3 speed gearbox, does anyone have a copy to hand they could post or give advice on how it's done. I guess I need to somehow clip the release bearing to the release arms and put a return spring on the clutch pedal somehow? Many thanks in advance all.

[Zetomagneto]

Fit the hammer head type release levers to the clutch pressure plate, swop the 3 speed release Assembly for the 4 speed release assembly, job done

[Ruairidh Dunford]

Mark,

Terry Griffin's solution to this is in this thread: https://www.austinsevenfriends.co.uk/for...p?tid=1251

I suspect that is the one you are remembering.

[Charles P]

Fit the hammer head type release levers to the clutch pressure plate, swop the 3 speed release Assembly for the 4 speed release assembly, job done

That's how I've done it as well. 
Mousetrap springs - never bothered.


Charles

[Mark R]

Many thanks both, I think the hand done drawings are what I remembered, potentially in the BA7C newsletter many years ago. 

Zeto, do you not have any way to pull the bearing back or do you just let it be pushed back by the clutch levers? I was worried about it disengaging with the cross shaft levers and turning a bit thus loosing location on the two flats?

[Zetomagneto]

I still have the spring on the clutch pedal which keeps the levers in contact with the release bearing, and the bearing stays in contact with the 3 levers on the clutch pressure plate.
Fitted new levers from Sevenworkshop and have a very nice clutch with slightly more travel.

Does anyone know if the new levers have the pivot point in a slightly different position 
as my clutch is a huge improvement with only fitting those levers, no new clutch.

[Ruairidh Dunford]

I think the pivot point on original three and four speed toggles differs between the two type and all reproduction ones differ again from those.

[Stuart Giles]

I've done this conversion several times. Haven't bothered with the mousetrap springs on the last few as they're an absolute pain to incorporate onto the 3 speed clutch cover -they're unnecessary anyway as the fingers can't come out of their slots once the setup is assembled.

Have had to cut back the cast in stop on the 3 speed gearbox casing each time to allow for a small amount of clearance between the four speed release bearing and the four speed clutch fingers.

Edit: remembered snapping the stop on one of the conversions...

[Dave Mann]

You mean like this Mark.     I fit 4 speed toggle levers and mousetrap springs and use a spring to pull the thrust bearing back.         The thrust bearing has been cleaned and is greased.

[David Stepney]

It look s as if the gearbox lid is on back to front in the last photograph.