Clutch Cush rubber replacement.

All horribly familiar. I changed mine according to the book shortly after I first took on my Dommie - 25 years ago now - and it wasn't a huge struggle.  Since then it's been impossible.  My 16H ones were swollen but not rotten, so I replaced them after shaving 2mm off the outsides to remove the swelling.  Les at Russell Motors (who sold be the new AN rubbers) failed to get the new ones in.  I now wonder if, next time, I might line the apertures with clingfilm and fill them up with silicone RTV.  I wonder if Andover Norton know about this?  Surely some supplier must?
 

I'm going through this very exercise at the moment.  My old rubbers were breaking up but are noticeably softer rubber than the new plastic replacements.

I made a special tool to compress the rubbers that had tubes to fit into the clutch centre , over the studs for the springs.  I called a mate in to help put the rubbers in whilst I used the tool with a 1.5m (5ft) scaffold tube to provide enough force to make space for fitting the thin cush "rubbers".
Ten minutes later, job done and quite pleased.  Then went to fit the cover plate only to discover the force had split the inside of the spring recesses, which is very thin.  Result: centre destroyed!

Have just ordered the proper tool from NOC shop, so will be trying again when it arrives.
Let the force be with you, but in small amounts!

Perhaps if we order some relacements direct  from India they may be of the correct dimensions and material composition ??.

A 5 foot bar is simply asking to wreck the spider.  It's far too high.  There's no logical reason for them to be so hard, and they won't even do their job if they are rigid.
I wonder if Jeff and Alan Hunter do the rubbers since AN don't seem to be able to?  Are there already alternative suppliers or are they all coming from one place?  Robert has a good looking plan...

Not sure if Roberts idea will be firm enough to withstand the forces it would have to take. However, using silicon or viton cord to make your own might be better? A 1 metre length of 1/4" Viton cord costs around £15, Nitrile (NBR) cord around £5.
This was done in a recent 'Classic Mechanics' magazine to refurbish a clutch, packing small lengths either side of the spider . You can at least specify something with a higher shure hardness number to hopefully take the forces.

A second thought would be to try soaking the rubbers for a period in brake fluid to help soften them? Works on air cleaner to carb rubbers.
Some videos show 'wintergreen oil and alcohol' as a means of softening too.

I do wonder if Andover Norton have any comments on why these rubbers don't fit? As has been said/found out, a 5' extension is not the solution to install, and not what would have been used on an assembly line, so it suggests that these rubbers are not fit for purpose? Surely it can't be everyone's clutches are out of spec and the rubbers are 'perfect'? 

George 

David, it was not the 3 legged spider which broke, it was the outer case.  As you say, with these hard inserts there is no effective "give" to provide the cush drive

Does anyone have a Shore hardness tester to check what the modern plastic inserts measure.
Then a NOS rubber needs testing to make a comparison.
My replacement inserts came from the NOC Shop, so perhaps the procurement person may be able to shed some light onto what specification is used for them.

The rubber inserts from the Andover Norton site do not look as shiny / plastic, so perhaps it would be worth trying these?
Philip

I may have written about this subject in a previous thread on this very subject so apologies for repeating myself.
I think the key to success is the tool that turns the clutch.  It needs to be able to apply a "pure torque" to which ever clutch part that is being moved.
Looking at the tool the OP has used I'm not surprised its started ro fail.  The turning force is being fed through a "dog leg" route.  The handle, ideally, needs to be in the same plane as the part of the tool that engages the clutch component.
To apply a "pure torque" there needs to be another handle opposite the existing one so you are pushing one end while pulling the other with, give or take. the same force.  To do a Triumph clutch the tool we made had an overall length of ~5 feet.  Still not easy, it was a two man and one woman job!  And plenty of good quality rubber lubricant.  Also, an extremely robust work bench and vice would be needed to react against.
As for hardness testing of the rubbers, the original specification needs to be known, from the drawing?  Hardness testing NOS rubbers that may be 50+ years old will not be reliable.  Likewise rubbers removed from and old clutch that have been through goodness knows how many heat cycles and covered in oil will not give reliable results.
I've just done a quick calculation, the tool I described to do the Triumph clutch being used by a 16 stone guy should easily deflect the rubbers, it didn't seem like it!

Looking at the smaller rubbers on sale from various sources ,it would appear that there are some that would appear to be better shaped to fit into the center.