Lotus Elan

Rear Suspension Overhaul

PostPost by: SENC » Sun Feb 11, 2018 12:50 am

Amazing what finding a stale donut leads to! While waiting for a cvds from elantrikbits, I've started pulling the rear suspension apart to identify what else needs to be done. So far, a totally "melted" bumpstop and shroud, dry-rotted lotocones, and questionable rear wishbone bushes have led to a fairly complete dismantling.

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The mucked up shroud and strut cleaned up ok, now I need to find a key/wrench to remove the damper from the strut and determine whether I have a rebuild or repair opportunity.

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Seeing what I have (and have out), I'm interested in your recommendations on things I should consider upgrading. I wasnt planning on replacing the bearings and have no strange sounds, but assume I should do so since I've come this far. Any recommendations on struts, dampers, and springs? Any real value to changing to 2.5" springs from 4"? Anythings else to consider?
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PostPost by: Bigbaldybloke » Sun Feb 11, 2018 1:36 am

While you have plenty of access, I?d fit a diff brace if you don?t already have one and give the handbrake tree a good service. I?ve fitted the small diameter springs for two reasons, 1. My spring cups on the struts were badly corroded. 2. I want to fit 14? miniltes on my plus 2 so need the added clearance and option to adjust the ride height. If your wheel bearings are definitely good I?d leave them alone, it?s easy to damage the strut and circlip groove.
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PostPost by: SENC » Mon Feb 12, 2018 3:57 am

Thanks. I plan to pull the diff to replace the pinion seal (I seem to be spraying a healthy amount of diff fluid), so will install a brace. The handbrake tree was removed by PO, so I need to go searching the boxes for bits - may as well try to get that working, too, while everything is out of the way.
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PostPost by: Bigbaldybloke » Mon Feb 12, 2018 10:26 am

There is a new handbrake tree on eBay at the moment
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PostPost by: SENC » Tue Feb 13, 2018 1:12 am

Was able to get at the dampers this evening - found they are Konis, for which I had previously found a receipt from the mid 80s.

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They are labeled Special "D", 86R 1371, Adjustable.

So, they are 30+ years old - send off and have them rebuilt, or replace? If you suggest replacing, do you have a specific recommendation?
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PostPost by: JonB » Tue Feb 13, 2018 9:14 am

SENC, a quick question - how did you take the damper units out of the strut?
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PostPost by: elj221c » Tue Feb 13, 2018 11:24 am

SENC wrote:They are labeled Special "D", 86R 1371, Adjustable.


They look like new. I think I would just get them checked by a Koni specialist.

They are the correct part. This leaflet is from my '84 purchased units. I've shown this before but to save the search.....

img001.jpg and


JonB, the internals of the original strut unscrewed from my strut tubes. I needed a pin wrench to engage in the Armstrong (AS1512) units on mine. I reused the same top caps. Sometimes the top of the tube is 'swagged' to stop the strut coming apart in service. I don't remember the replacement being too much of a problem.
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PostPost by: SENC » Tue Feb 13, 2018 11:37 am

JonB - I used one of these, found on Amazon, with a 1/2" drive breaker and a few choice words.

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img_20180213_063512.jpg (22.84 KiB) Viewed 1098 times

OTC 7463 Universal Small Gland Wrench

elj - thanks!
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PostPost by: nmauduit » Tue Feb 13, 2018 2:38 pm

SENC wrote:They are labeled Special "D", 86R 1371, Adjustable.

So, they are 30+ years old - send off and have them rebuilt, or replace?


First test would be to hold them vertically and actuate them fully a few times, feeling/hearing for bubbles (which should eventually go away when in operating position) and weakness of one side relative to the other. If similarly firm, they may not necessitate overhaul (yours look pretty good and they are strong units on a light weight car). If in doubt you can reset them identically before testing.

If you still want to be reassured by a professional, it may be easier to get them tested on a bench and calibrated/balanced first, this not necessitating seals that may be specific to these Konis... I had a pair done a couple years ago by a damper professional specialized in Bilstein, he found out that one was a fraction of a turn stiffer (1/8th iirc) than the other then set them identically and marked the setting. One can then still alter the setting homogeneously by turning the shaft by the same amount on both shocks. I don't remember the cost for bench testing and setting but it was not expensive, 30 comes to mind (could have been per shock or for both), they also had a 80 flat fee for reconditioning (which they would offer if they have the parts, seals etc).
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PostPost by: SENC » Tue Feb 13, 2018 3:06 pm

Thanks. I suspect one has been losing oil, both from the totally dissolved bumpstop and shroud on that shock and because it has almost no resistance for the first inch or two from full extension. Adjusting it more than the other made it more similar, but obviously not quite right. Talking with TrueChoice now about inspecting them then rebuilding as necessary.

Re: wishbone bushings, I'm thinking of trying the poly bushings. Any general feedback? They are notably cheaper from the British vendors than the US vendors, whereas other items seem more similar in price (after factoring the exchange rate) - any differences I should be aware of?

Also need to order new bumpstops, but haven't found any of the style that came off my dry damper. Is any one style or source better than the other?
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PostPost by: jbeach » Tue Feb 20, 2018 4:29 pm

Hi SENC,

I'm in South Carolina and going through an amazingly similar rear-end rebuild process as you. Like you, I purchased CVs from Elantrikbits, I found 80s red Konis in my strut tubes, etc.

I'm a few steps ahead of you, but not much. I removed my differential and have replaced the seals and bearings. I decided to replace the output shafts with uprated ones from Tony Thompson.

I'm doing something interesting with my springs. Tony has just developed a new product - adjustable spring perches that allow use of the original 4 inch springs - I'll be installing them. I have cut/grinded off my fixed spring perches and will weld the new ones in their place this weekend.

OK, so maybe I'm going WAY overboard on this, but I also purchased new yellow Konis from TTR. While i originally purchased the CV drive shafts from Elantrikbits because they supposedly don't require droop limiters, I went ahead and purchase the yellow Konis with the shorter, droop limiting shafts, just to make sure.

I'm going with poly bushings for my lower wishbones. When I did my front, I stuck with the original rubber/metal bushings to maintain the Elan's smooth steering feel, but from what I've read and heard, the polys don't affect compliance or feel as much in the rear, so I went for the greater durability they apparently afford.

Because one of my outer axles felt rough, I'm rebuilding the hub assemblies with new bearings and uprated axles. Getting the original axles to disconnect from the hubs was a huge PITA, so I don't recommend undertaking this part of the project unless necessary.

As a final point, I just ordered the Aeon bumpstops from Ray at Rdent ($19 each). Rohan recommends adding spacers from the +2 to bring the bumpstops into play a little earlier in the suspension compression, but Ray doesn't presently stock those, so I'm going to figure out something similar from another source.

My old Konis feel about as perfect as possible, with no evidence of leaks. They are the same as yours. If you want them, I'd be happy to give them to you for free if we can figure out a convenient way to do the physical handover. I'll confess, I hate going through the process of packaging and shipping things. Do you ever come through Columbia?

Here are a few photos, in case you or anyone else reading this might be interested.

Good luck with your rebuild!

-John

img_3444.jpg and
New Components


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TTR Adjustable Spring Perches


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Differential with TTR Output Shafts, Bearings & Seals


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Old Output Shafts - Probably didn't need replacing, but, oh well!
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PostPost by: SENC » Tue Feb 20, 2018 5:58 pm

Thanks for your post, John. I'll pm you my contact information - we should connect to share what we learn, tips, and tricks, etc. - and meet up once cars are back on the road.

I've sent my rear dampers to TrueChoice so hopefullt will be set - but may take you up on your offer if one or both are unserviceable.

Since I'm still anticipating a full reno in a couple years and not experiencing any obvious bearing issues, I'm not going to pull the hubs nor change out the strut housings or springs right now - just going to use this overhaul to fix what is broken and develop a list of things to replace or upgrade when the body comes off. I have decided to try the poly bushings, too - I figure if I don't like them I'll have an opportunity to replace themnat reno time. Thanks for the tip on the aeon rubbers, I'll give Ray a call as I need a couple other things, too. I'll let you know if I come across spacers for the plus 2 - have you checked SJS? Their list is pretty extensive. I don't think I have Sue Miller's Plus 2 catalogue, but will look.

I do plan on pulling the differential, given the amount of fluid I'm sparying back there, to replace the pinion seal - any words of wisdom?

I'm still debating the handbrake. It was dismantled by the PO so off the car, now. I know that job will be much easier body off, but it sure would be nice to have. How have you found working on it?
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PostPost by: jbeach » Tue Feb 20, 2018 11:41 pm

Your decisions make complete sense.

Re: pulling the differential, I've seen posts describing the process and hard and frustrating, but for me it went like a breeze. That could be because I watched this YouTube video before I proceeded. It's a bit quirky, but, for some reason, just watching it made my diff removal a very slick process.

https://www.youtube.com/watch?v=-12F0s58y6k

Removing the output shafts and replacing the seals was a simple process, once I got a slide hammer that fit. After removing the circlips, a few gentle taps was all each shaft needed.

Good luck!

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PostPost by: SENC » Wed Feb 21, 2018 1:51 am

Thanks, John. Will check that out.
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PostPost by: SENC » Wed Feb 21, 2018 3:46 am

Found these bump stops for a TR6/TR7 front suspension while digging around for progressive bump stops vs the single blocks that seem most available. Thoughts about whether these would useable and preferable?

https://www.bpnorthwest.com/bump-stop-polyurethane-front-tr7-tr8.html?gdffi=7c26fa82af054ed48c16509776f45115&gdfms=520E4C6895094215BB8419C9EFA2C94D&gclid=EAIaIQobChMI1fPB-4q22QIVwbjACh3E3wf6EAQYAiABEgIJJPD_BwE
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