Lotus Elan

Superflex trunnion bushes

PostPost by: jono » Tue Apr 11, 2017 2:24 pm

..knackered after only 9,000 road miles.

The ends had extruded and torn (perhaps my fault for not using the original trunnions caps but there is no mention of this in the instructions).

When I got them out the bore of bushes had worn into an egg shape - almost completely through.

I have gone back to nylon bushes cheap enough to change on a regular basis. The steering and front end feels so much tighter now - you don't realise how much you loose when it happens over time.

I also returned to metalastic bushes on the back after 6,000 miles with Autobush poly bushes - these too had worn in a strange way.

No substitute for original kit!

Jon
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PostPost by: 661 » Tue Apr 11, 2017 7:22 pm

I recently spoke to Tony Thompson about the fitting of these bushes and he said the end caps are not used. I must say, it looks like the caps would ordinarily offer a wear protection.
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PostPost by: dunclentdr » Tue Apr 11, 2017 7:49 pm

I'm in the middle of fitting these as part of suspension rebuild and have fitted end caps to the trunnions - do you know why TT advises not to fit them?

Thanks

David
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PostPost by: 661 » Tue Apr 11, 2017 9:28 pm

dunclentdr wrote:I'm in the middle of fitting these as part of suspension rebuild and have fitted end caps to the trunnions - do you know why TT advises not to fit them?

Thanks

David

No! He said the collars of the bushes articulate with the flat inner side of the wishbones. I suppose the thinking is that it doesn't really matter if they rub against a metal wishbone or a meal end collar.
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PostPost by: jono » Wed Apr 12, 2017 7:31 am

..they do but in the process, the flanges wear and then get torn. There is no specific instruction to use the trunnion covers but some do - it would mean that the polybush has a flat surface to turn against which makes some sense to me.

That said, I won't use them again as I see no benefit over the original, and cheap, nylon kits.

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PostPost by: 661 » Wed Apr 12, 2017 8:26 pm

I'm building mine with the 26R wishbones which are a flat surface
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PostPost by: Frogelan » Wed Sep 27, 2017 8:01 am

I will be approaching this problem soon, so I am interested in the debate.

I would have a guess that TT suggests the end covers are not needed for racing use in case these have some effect on the functioning of the suspension (friction). I'm sure some racers reading this would have some observations (they are probably having special ones made up).

Such bushes need regular maintenance and 9000 miles sounds a very good lifetime for this type of bush which are probably intended for track day / potter to the pub use !
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PostPost by: Orsom Weels » Wed Sep 27, 2017 9:18 am

Frogelan wrote:I will be approaching this problem soon, so I am interested in the debate.

Such bushes need regular maintenance and 9000 miles sounds a very good lifetime for this type of bush which are probably intended for track day / potter to the pub use !


Except that original kit did over 30,000 miles in my +2 & I only replaced them as I had the front end stripped down for other reasons. Had that not been the case, I suspect they would still be in there after another 10,000 or so.
A friend has recently spent a small fortune on replacing all his bushes with Superflex kit on his Sprint & on East Anglian roads you really can't tell the difference. To say he's disappointed doesn't really cover it !

Regards, Tim
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PostPost by: Frogelan » Wed Sep 27, 2017 9:29 am

I'm not sure bushes are an exciting subject, but what I can say (racer's experience), is that on a car where the suspension is not easily adjustable (geometry), very patient machining allows you to achieve precision (it takes about a week to perfect...).

For road use I share your view that special bushes are very unlikely to be useful: quality shock absobers might be a better route (NB: I rarely go to Norfolk, but often potter around Suffolk).
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PostPost by: gus » Wed Sep 27, 2017 11:30 am

IIRC there are two metal covers and a seal. The inner metal cover does not move relative to the bush, the outer does not move relative to the wishbone. The seal keeps the lube inside.

Why would you want to delete these?
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