Author Topic: removal of 1930 S6 clutch - new douglas owner, help appreciated  (Read 3971 times)

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Offline Ian Dabney

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I have recently acquired my first Douglas, a 1930 S6, in roadworthy condition. I am having issues with a dragging clutch and the previous owner said it could slip. On reading my 'Book of the Dougals' it says you either need a puller or the flywheel/clutch is self extracting. I enclose a picture of the flywheel/clutch on the S6. It looks like it has a castellated ring retaining the flywheel/clutch on the shaft.

I would appreciate the advice and experience of the group on what tools I need and what is the best approach to stripping the flywheel/clutch for inspection,
many thanks
ian

« Last Edit: 12 May 2014 at 22:18 by Dave »

Offline eddie

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Ian,
       From the photo, it looks as if you have removed the 6 screws that retain the back plate. Before going any further, replace the 6 screws so that the clutch comes away complete. As you mention, the flywheel has a retaining ring that captures the flywheel nut. All you need is a socket deep enough to go onto the nut, and some means of preventing the flywheel from turning. Undoing the nut will extract the flywheel - but some force will be needed to free it from the taper. Having got the flywheel off, be careful as you dismantle it - the centre boss has tracks for 2 rows of crowded rollers and 1 track of balls (for the thrust). These balls and rollers can cascade across the workbench as you dismantle it! From the photo, I see you have already removed the spring plate and springs, so there is nothing else that is likely to shoot out across the workshop as you strip it down. With it apart, you will find that it has dry corks in a thick alloy plate, and is a single sided plate. Provided the corks are not excessively worn (still standing proud of the plate) and not loose in the plate, the plate should still be serviceable. (there is not much in these clutches to go wrong!). If you investigate the operating mechanism, you will find that the ring that carries the three rollers can be fitted in 3 alternative positions - this is to give some adjustment to the position of the operating lever, which should have some free movement when the clutch is reassembled, but with the cable disconnected. If the lever is pressing against the inside of the primary chaincase, the clutch will slip! Whilst everything is stripped down, check the lengths of the clutch springs. If any have collapsed, get a new set from LDMCC spares (assuming you are a member). If you have to reuse the old ones, arrange them in pairs according to length and then fit them opposite each other so that the plate lifts square to the flywheel.
   If you come across any other problems, get back to me.
   Regards,
                 Eddie.

Offline Ian Dabney

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Eddie,
Many thanks for your help,
regards
ian

Offline Doug

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Ian,

Further on to Eddie's description of removal. The castellated ring nut serves two purposes. It provides something for the flange of the flywheel nut to bear upon and extract the flywheel, and it serves as a jam nut to keep the flywheel nut from working loose. So first loosen the ring nut one turn, but do not remove. Then loosen the flywheel nut. After a turn it will contact the ring nut and stop. Continue turning until the flywheel nut pops the flywheel clutch loose from the crankshaft taper.

As Eddie says, you take the clutch apart after you have the flywheel off.

One of the critical components that can cause the clutch to drag is the carrier sleeve. This is the sleeve that slides on the flywheel hub, on which the clutch disk and sprocket revolve. If the fit on the hub is too loose, the clutch disk can tip, dragging along its peripheral edge. Sometimes the sleeve is found to be distorted slightly out of round, preventing an accurate fit. If this is the case, the carrier sleeve can be lightly honed true and the hub of the flywheel reduced slightly in diameter and a sleeve pressed on to build up the diameter. This can be of steel, like the flywheel, or I prefer bronze.

-Doug

Offline Ian Dabney

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Doug,
Many thanks. Can  please confirm that all treads are anti clockwise to undo. Also should I make up a tool to be able to rotate the castellated ring. Sorry they may be simple questions, but I don't want to cause damage,
regards
Ian

Offline Doug

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Ian,

Yes, both the ring nut and the crankshaft nut are right-hand threads; counter-clockwise to loosen.

-Doug