Bending Clutch Levers

[Parazine]

John P:

There's your problem! You've been using Millimetric measurements instead of proper inches. They don't mix you know!

Nick Turley:

I assume 1/4" is correct for the four speed box. Does anyone know the correct dimension for three speed gearboxes?

[John P]

Actually, on the measuring front, I did find a problem.

Although I was in engineering all my working career I now have very little in the way of measuring equipment and initially was measuring the various dimensions using the depth facility on a cheap digital vernier bought from Lidl.

I just couldn't get repeatable results even allowing for the fact that this wasn't the best way to do the job so I went back to an old Mitutoyo vernier with manual readings.   Instantly the results were much more consistent any variation being what you might expect measuring worn parts in this way.

The Lidl item seems fine used for measuring lengths or diameters using the jaws but the depth rod is both very slender and also not very well supported, especially compared to the Mitutoyo, so I suspect flexing here may have affected the readings.

It's a bit annoying as I've spent a lot of time checking and re-checking the measurements but I guess I should have know better.

John.

[Parazine]

It's worthwhile touring car boot sales (when they're back up and running) and steam fairs etc, engineering measuring equipment can be picked up at reasonable prices, especially if it's imperial.

eBay is best avoided as sellers seem to think that everything will eventually sell for an inflated price.

[Stuart Giles]

Out of interest I did speak to Seven Workshop and apparently both types of toggle are investment castings which surprised me as I'd expected the 3-speed ones would have been laser cut or wire eroded from plate but this may explain why some people are reporting they can crack if bent.

Although it's a bit of a pain to do I think I'm going to have to try to alter the height of the pegs as, apart from anything else, I don't have access to oxy-propane or similar to do the heating.

I have never tried bending the reproduction investment cast levers. Firstly I was concerned that they might not have been HIP treated after being cast, and so might crack/snap; secondly, if they were HIP treated a random re-heat might not do them any good either. I drill and tap the 'dent' in the clutch plate groove. Screw in some grubscrews cut from the thread of capscrews, adjust the toggle heights and then tack weld the grubscrews at the back of the cover plate. Unless you're very lucky this is likely to be an iterative process requiring the removal/replacement of the cover and plate as the grubscrews are adjusted. The different paint pen markings in this photo  ensure that the  pressure plate and cover always go back the way they came apart.

[Nick Turley]

The same

[John P]

Stuart,

That would ideally be what I'd like to do but, as far as I can see, once the lining is riveted to the clutch you can't access the grub screw / plug to make any adjustment.

At the moment the clutch is still attached to the flywheel so I haven't been able to check this out.

John.

[squeak]

The grub screws are in the cover plate and the linings are on the pressure plate and the flywheel, thus not in the way. I endorse Stuarts colour coding of components for reassembly

[Ivor Hawkins]

For the past 50 years, I’ve bent clutch levers cold without issue, but after reading this thread, I think I’ll get the oxy acetylene out!

[AustinWood]

I tried to bend one once. It snapped!

[Steve Jones]

Whilst I almost always agree with Nick, on this occasion I have to say that I've used the grub screw method for a lot of years with total success. However you do it, it's important to get the levers set correctly, most importantly, all three must be at the same height and the posts, levers and pins need to be in perfect condition; if in any doubt, replace with new. Once you've done all that you'll get a smooth and progressive clutch that isn't 'on/off' and with a reasonable amount of movement.

Steve