rear struts and shock tube packing nut

PostPost by: TomMull » Mon Mar 11, 2024 3:29 pm

I'm installing a new chassis and trying to transfer all of the use-able bits to the new one, presently the rear
suspension.
I've removed the red Konis from the rear strut tubes.They seem to be OK. This was straight forward with the exception of the packing nut at the top of the tube. I took them out because if I turned the struts upside down the oil ran out of the top nut. I can't seem to find a breakdown of the top packing seal. The picture below shows everything that was in the nut.
packing nut.jpg and

If you scroll down on The-Lotus-Elan-Research-Hub, https://elantrikbits.com/lotus-elan-blog/koni-rear-strut-rebuilding/ you will find they show a series of packing washers. There's nothing like that on mine. Perhaps a later version? I can't seem to find a parts breakdown anywhere.
Tom
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PostPost by: 512BB » Mon Mar 11, 2024 5:12 pm

'This was straight forward with the exception of the packing nut at the top of the tube. I took them out because if I turned the struts upside down the oil ran out of the top nut'

What packing nut? Do you mean the securing collar at the top of the strut? In any event, you do not show the correct Koni securing collar, which is why I suspect you have all that other crap fitted by a DPO. Non of it should be there. If nobody else beats me to it, I can take some pictures of the correct collar tomorrow.

If you do insist on driving your car upside down, oil will escape from the top of the strut, slowly. Oil that the damper sits in that is, not oil from inside the damper, if the top seal on the damper is in good order that is.

Leslie
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PostPost by: TomMull » Mon Mar 11, 2024 6:22 pm

Thanks for the reply Leslie.

Can you possibly steer me toward the correct top collar? A picture might help. The car is a 1970 Elan Plus 2 S.

Seems there should be a diagram somewhere. My reprinted FSM does not have one.

It also appears my nut is identical to the one in the link on my first post. That top nut appears to be a "packing nut" and is in two pieces that should be holding some sort of packing between them. Otherwise there would be no reason for the two piece top nut.The black rubber seal appears to me designed to keep dirt and water from getting into the packing nut, and not for keeping the oil in housing.

It also seems that Koni replacement shock inserts come with mounting hardware, perhaps updated versions of the nut too. But I don't need new shocks.

Tom
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PostPost by: 512BB » Tue Mar 12, 2024 3:50 pm

Here you are Tom. As I said previously, the fittings you show are a lash up, and nothing to do with the correct way to secure any insert. I could telll straight away because the hole in the collar you show is far to big, and that is why there are an assortment of washers, to try to close up the hole. That is a terrible bodge.

The orange insert in the pics is the Koni and its associated collar. The red insert is an Armstrong and its collar. The collars are not interchangeable as each insert is completely different at the top, including the thread depth. Note the small hole just below the shoulder at the top of each collar. That is to allow air to escape, as the oil the insert sits in expands when it heats up in opperation. Hence my comment about inverting a strut and oil will eventually make its way out of that hole. Oil will also be emitted from that hole if the strut is over filled with oil on assembly, as it expands when it heats up.

The last thing to note, is that there should always be a 1 - 2mm gap between the underside of the shoulder on the top of the collar and the top face of the steel strut, AFTER the collar has been tightened. That ensures that the insert is being held firmly down with no movement AT ALL of the insert when fitted in the strut, and that the air expansion hole is clear. If there is no gap when everything is buttoned up, the unit should be disassembled and a large washer in either steel or nylon should be dropped into the bottom of the strut tube for the insert to sit on, thus raising the insert, so that there is that 1 - 2mm gap.

If the usual suppliers in the States cannot sell you the correct collars, try Koni themselves or a Koni agent.

Good luck.

Leslie
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PostPost by: TomMull » Tue Mar 12, 2024 6:26 pm

Thanks, Leslie, I do appreciate the time and effort you've put into this and I apologies for my ignorance.
Please bear with me. My original post was confusing. I'll try to clear that up. The photo in that post is mine, the link comes from "The-Lotus-Elan-Resource-Hub" website. I used that as a resource since it appeared to me to be the same strut as mine. The picture at the end of this reply is mine.
The following details are mine also.
The shock piston is 7/8 Inch exact.
The washer inside diameter is 59/64.
I find no vent hole in the nut.
My goal here is to identify the proper nut arrangement and find a source for same.
Below is my insert with nut.
My goal is to find a new or replacement nut complete.
Tom

koni 1.jpg and
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PostPost by: 512BB » Wed Mar 13, 2024 9:12 am

I have to confess Tom to not following the link you posted, but after having now done so, it appears that the dampers that were rebuilt in that article, and yours, are very old, and have been superceeded by the dampers that I show, with a far simpler retaining collar with no additional parts.

I cannot therefore offer any further advice other than to contact Koni direct to see if they can supply the parts you require.

Best,

Leslie
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PostPost by: Quart Meg Miles » Fri Mar 15, 2024 1:26 pm

As 512BB mentioned, in passing in his first reply, there should be about 50 cc (ml) oil between the strut and its housing in order to help keep it cool. That might be what poured out when you inverted the whole assembly.

It's easiest to pour it in before you fit the retaining nut.
Meg

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