Coil to diaphragm clutch conversion confusion

[Colin Lindsay]

Ever get one of those mornings where the brain will not work and everywhere you turn to for reference only confuses things? Welcome to April 13th...

I decided a while back to keep the original coil spring clutch on the Herald convertible and rebuilt the gearbox clutch release arm accordingly. Now, as I've found I have two brand new original B&B diaphragm clutches it makes sense to use those. I need to match the correct release bearing to the correct clutch. I had believed that the flat faced bearing, to the right in the first photo below, was for coil clutches and the thicker rounded-face version on the left was for diaphragm, but having checked a few of my spare release lever arms I find early cars, which were coil spring clutch, with the rounded bearing. I've checked online but cannot find the definitive photograph that will confirm and some suppliers are just listing a one-size-fits-all part with the same photograph.

  Secondly I've checked the carriers and found a complete mixture of bearings and carriers; some short carriers and some long but each with different bearings fitted. The last photo on the right shows the early alloy gearbox lever arm but it has the rounded bearing and long bearing carrier, and it dates from 1959 / 60 so there's no chance of using my spares as a definitive reference. As a lazy man's method of confirmation can anyone confirm that for a Herald with diaphragm clutch (and yes I've swapped flywheel and slave cylinder) I need which bearing on which carrier? Flat on short / flat on tall / rounded on short / rounded on tall?

    

 

[Mathew]

Sorry its the best pic i can find of the bearing at the moment, it looks like the one on the right is the one for the spring clutch.

[Pete Lewis]

in general  clutch design  a coil cover has a flat platen so you need a pretty flat bearing to match it as the two faces stay the same as the cover is operated

a diaphragm cover needs a rounded face as the fingers have to slide over the face as the cover is operated  

a diaphragm cover is normally shallower than a coil so has a deeper carrier to make up the change in stand off .

the coil cover may use a semi rounded as a self centring idea if the geometry of the throwout lever means 

concentricity is let say ...a floating variable 

Pete

 

[Mathew]

This is the bearing to my 1500 clutch kit

[Colin Lindsay]

Excellent - so I'm correct for the first part ie the bearing. Now: the bearing carrier... I would have said long for diaphragm and short for coil, but maybe it's not as simple as that?

[68vitesse]

From a John Kipping parts catalogue.

Regards

Paul.

 

[Colin Lindsay]

Thanks Paul; of course the only bit he doesn't mention is the size of the bearing carrier (I have three sizes!) but a quick reference shot of a 13/60 seems to confirm it's the longer carrier and the rounded bearing.

Now all I have to do is work out how one of mine ended up with a short carrier and a round bearing, which wouldn't work on any clutch...

[Steve P]

I would do the same as i did when i changed my Vitesse to a paddle clutch,try diferent carriers and see what the geometry of the arm is after,easier on a bare chassis and engine.

Steve

[Pete Lewis]

colin yes correct    thats the .....long an short of it 

[Colin Lindsay]

Ok so have killed my alloy backplate and in removing the flywheel etc again have also killed the locking tab washers on the flywheel bolts. They were quite rusty but I didn't think they were so bad as to fall apart, so need replacements. 

Part number is 102076 NLA as usual. I see the later cars don't use them; early bolts are 105116 but suppliers seem to be replacing them with 138526. As luck would have it I've just bought four of those from Paddocks. I'm assuming they are some kind of interference fit and don't need tab washers?

[Mathew]

Put a bit of thread lock on, just in case!