Lotus Elan

Trunnion Bushes - Second Rebuild In Thirty Years.

PostPost by: ceejay » Fri Jan 04, 2019 9:18 am

What's that you say?... Cant be right.

Yup, the original and piddly Triumph Herald trunnion bushes were thrown in the bin... and replaced with highly durable custom machined Red Urethane bushes and stainless steel crush tube.

Learn More here - Complete article - And nothing to sell - Something that has worked for us.
http://elantrikbits.com/lotus-elan-blog ... on-bushes/

Enjoy.
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PostPost by: 69S4 » Fri Jan 04, 2019 10:05 am

Converted in the early 1980's - I thought these things lasted for ever! :lol: :lol:

For those of us without machining capability (or ability) I see that Superflex are selling them for ?26.00 + vat. https://www.superflex.co.uk/proddetail.php?prod=SF225-1321KSS

Considering I change the std bushes just about every time the front is stripped down that would seem to be a good upgrade. Unless there are other issues with pu I'm not aware of?
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PostPost by: 661 » Fri Jan 04, 2019 12:46 pm

CeeJay, having just had some custom bushes made, I wonder by how much you make the spindle oversize?
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PostPost by: ceejay » Fri Jan 04, 2019 9:32 pm

Graeme.
The bore of the trunnion was bored to 22.19mm (0.817")... but the ID was really dictated by the amount of ovality (Wear) that had to machined out. Wall thickness of the housing would have been 4 to 5mm thick. And of course a new stainless crush tube is required to match the urethane bushes... so think about what you are doing before you jump in. Yes, I understand that not everyone has a lathe in the work shop.
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PostPost by: ceejay » Fri Jan 04, 2019 9:41 pm

The super flex kits looks to be the goods if you cant make these your self. But be aware that if the trunnion bush housing is worn and out of round, the super flex bushes will not solve the problem entirely, just make sure to inspect carefully, and measure carefully.
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PostPost by: Quart Meg Miles » Sat Jan 05, 2019 10:17 pm

I'm concerned that the dust traps are discarded. The "crush tube" (it isn't, it's just a spacer) has to leave a clearance between the wishbone ends and the plastic and that's where dirt gets in.
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PostPost by: 661 » Sat Jan 05, 2019 10:37 pm

ceejay wrote:Graeme.
The bore of the trunnion was bored to 22.19mm (0.817")... but the ID was really dictated by the amount of ovality (Wear) that had to machined out. Wall thickness of the housing would have been 4 to 5mm thick. And of course a new stainless crush tube is required to match the urethane bushes... so think about what you are doing before you jump in. Yes, I understand that not everyone has a lathe in the work shop.



Apologies, communication lack of clarity on my behalf. I was asking how much longer you made the crush tube over the width of the trunnion with top hats in place, ie clearance each end?
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PostPost by: ceejay » Sat Jan 05, 2019 11:52 pm

Graeme

There needs to a small amount of clearance... make the stainless tube 5 to 10 thou longer (wider) than the urethane bush.
The tube sets the bush preload, when the nyloc nut on the bolt that passes through the tube, it will (Should) provide the correct working clearance.
The urethane (Red) has the correct hardness for automotive suspension bushes... and yes, I see lots of others of blue colour... but some are made to soft.
You don't need the dust covers, but you could still include them if you wish, but I discarded them more thirty years ago, its your choice on that one.
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PostPost by: awatkins » Sun Jan 06, 2019 5:00 am

Crush tube? Preload? Are we talking about tapered wheel or differential bearings right now, or are we talking about trunnions?

If we?re talking about the nylon plain bearing used in the front suspension trunnion, the words preload and crush tube are not applicable.
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PostPost by: ceejay » Sun Jan 06, 2019 5:05 am

Probably best if you just go read the blog article again.
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