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3-speed clutch

I've just renewed the clutch linings in a 3-speed gearbox. Whilst all was apart I have also renewed lever posts and pins and fitted grubscrews to allow adjustment of the 3 x clutch levers to the published 1.25" distance from the clutch plate. On assembly of the clutch and gearbox I have very little clutch working movement and although it's partially releasing I am unconvinced that it will be sufficient once all is back in the car.
Should I be expecting a complete release of the clutch when first assembled and on the bench?

Location: Newbury, UK

Re: 3-speed clutch

Adrian.

The test i usually do is to put the box in top. Hold the output spide. Press the clutch. Can you move the spider? If you can it works. If you cannot. Or it is hard its no good.

Personally I set 3 speed levers by putting a straight edge across the bellhousing. Then set the levers so there is 1/4 clearance between them and the straight edge. I use a drill or a bolt as a go/no go gauge. A 6mm one will do also.

I set them from the bell housing as the mechanical parts of the clutch on the grlearbox are all standard sizes. Thus more or less identical if you swap the release bearing or the shaft etc (ok there will be some wear).

By setting off the clutch plate or flywheel you are really dealing with components that move. Replacing the front crankcase lip always seems to be very inaccurate in terms of lateral accuracy. The clutch clearly wears so where it is is dependant on the state of the linings. And the flywheel can be anywhere on the crank taper.

Mind. Ive know engines to happily run with 1/16 endfloat on the crank so you takes your pick

Re: 3-speed clutch

Adrian

Did you remove any 'excess' grub screw from protruding through the back of the cover plate? If not, this will restrict movement of the pressure plate during clutch disengagement

Location: Farnham

Re: 3-speed clutch

Thanks for the ideas Hedd - good point about setting from moving parts - I'll try your method.

Location: Newbury, UK

Re: 3-speed clutch

Thanks David, the grub screws are protruding. I haven't measured it but at a guess I'd say it's probably less than 1/16". What sort of clearance is there reckoned to be (if any) with clutch disengaged?

Location: Newbury

Re: 3-speed clutch

Adrian, I have always ground them flush on the back to avoid interference but having said that 1/16 doesn't sound very much. I will put some bits together to refresh my memory

Location: Farnham

Re: 3-speed clutch

David, some of the modern tab washers for the crankshaft nut are not the same shape as original, when the tab is bent up on only one flat of the nut the edges of the washer can foul the sides of the indent on the clutch driven plate and give clutch drag if not noticed. You always need to check that the driven plate sits flat on the flywheel lining before assembling the rest of the clutch.
This can be a real drag (literally!) if you have the engine fitted before you find out. Ian M

Location: Bristol

Re: 3-speed clutch

David forgot to mention a significant amount of clutch travel can be lost if the pedal cotter is fitted the wrong way, nut must be at the bottom of the pedal. Ian M

Location: Bristol

Re: 3-speed clutch

Thanks for both points Ian - a couple more checks for the weekend examination and rebuild. Cotter comment particularly interesting - seems obvious but confess to not having given it too much thought when reassembling.

Location: Newbury

Re: 3-speed clutch

On another note. Does anyone use tab washers o n the clutch cover plate?

I never have. Just a normal spring washer

Re: 3-speed clutch

Yes Hedd,me always and home made ones at that!

Location: Bristol

Re: 3-speed clutch

I just use spring washers.

Re: 3-speed clutch

Ian Moorcraft
David forgot to mention a significant amount of clutch travel can be lost if the pedal cotter is fitted the wrong way, nut must be at the bottom of the pedal. Ian M


Very true, but I assumed from Adrian's post that the flywheel hadnt been disturbed?

Location: Farnham

Re: 3-speed clutch

Apologies David for sending my replys to you instead of Adrian Senior moment I'm afraid.

Location: Bristol

Re: 3-speed clutch

Ian, I know the feeling!

Location: Farnham