Thanks all for helping to figure this out.
I think as Lee says someone did go to a lot of trouble on this so it would be good to make it work. But it does not have a distance tube (like Musky describes). So the bushes rotate around the spindle and the small spacers/rings inside the fibre washers have to be exactly right to stop end float (like what Richard says). So if it’s over tightened (like Musky says) or gets water in it and freezes up then the spindles turns in the frame etc. hence the failure.
So maybe I could get someone capable (not me) to line bore (?) through the current bushes to fit a distance tube. Or drive the bronze bushes out and start again. I’d be reluctant to just refit new spacers/rings tho maybe they could be re-designed and made waterproof.
A side note - C&D unfortunately don’t have silent blocs currently as they say the quality of what’s around is too low.
Its BSA club night tonight so those guys may have some ideas too.
All further thoughts very welcome.
And Ed – when I get this sorted I’d like that medal you mention – thanks.
Hi Mike, just realised we’ve met at the Taranaki rally (I think) :-)
Britishspares (for once) took on my complaint on the blocs, and sent them to John Saywell to be machined down in o.d. This was done several years ago on circa 20 sets, but maybe they still have the machinied down blocs in stock?
I’m still not sure if the designer of yr s/a bearings meant the spindle to form half of the bearing, but I agree with Dutch that if he did, then the metal rings inside the fibre washers have too little bearing area, evidence of which can be seen on one bronze bush having a groove cut in it. Maybe the fibre washers were also intended to control end float?
I’m not impressed with the idea of doing the spindle nut up just the right amount to spring the frame and get just a small amount of end float, it might work in practice but does not seem a “technically correct” design
I think I remember a discussion on whether the swing arm does or does not have a “step” in diameter to prevent the blocs pressing in too far, mine does have this step so there is no need for a centre tube, unless the bronze bearings are supposed to be turning in the swing arm.