Shock absorber seal replacement (Aurelia but non-original)

[williamcorke]

B20-2517 came with what I think must be a homemade rear telescopic damper conversion. The car was raced in Spain 'in period' and the dampers are made by Record, a company which still exists in France and had a Spanish sister company in the 50s and 60s. The dampers were clearly made/sold in Spain.

They are nice quality units which I've taken apart to find minimal wear.  However the top seals need replacement as the rubber has hardened over the decades, and the ability to keep all your oil in is obviously critical to function.

The original seals are made by Goetze, and have OD of 37mm and ID of 11mm with a garter spring. 7mm is the height. There are two steel washers, top and bottom, bonded with the rubber, to strengthen the part, which locates the central rod. The centre of the part is 4mm higher than the strengthening washer, presumably to provide more locating contact area for the rod.

So far I have contacted Record in France, Simply Bearings and a couple of damper rebuild specialists without any luck. Google didn't help either...

Does anyone here have any bright ideas about where I should look, or know of a company that could remake such a part?

Of course I could buy a pair of Konis or whatever with the same max/min length, but I'm interested to see how the period set-up performs.

[williamcorke]

Update.

Record in France replied (their Directeur Commercial, no less). I was wrong about Record Spain vs. Record France, which were never related companies - see fact sheet below. Record Spain was bought by AL-KO, a German company in the 1990 and still makes shock absorbers.

Very helpfully, they also pointed me in the direction of "Emmetec in Italy which distributes all kinds of internal and external components for any types of shock absorbers.".

I have found a shock absorber top seal with the right dimensions on the Emmetec website, and now need to persuade them to sell me fewer than 10!

[impaw]

Well done!
Nice of them to point you in the right direction 👍

[GG]

Surely two seals to use, and eight for spares will make you the English distributor for seals!

[williamcorke]

Perhaps in a few years I'll be able to sell the spare seals to myself at a profit. You need degree level man maths to do that.

[timdaw]

Did you manage to get the seals? My car is also fitted with a telescopic conversion. I changed from Spax to Koni's, (from a Triumph Vitesse!) and they are noticeably better! Of course yours will be a different spec. They were about £90 each, an alternative to 10 seals and uncertain performance? Nice to keep a period mod though!

[williamcorke]

Performance of the 50s/60s modification is unknown, but as I have managed to rebuild the shocks using new 'flying saucer' top seals, I will be able to experience whatever it was in period before spending money on modern replacement dampers.

I'll post here the incredibly detailed advice I obtained from Leda in the UK. It's a deep dive, so probably not for everyone but I found it very interesting.

[williamcorke]

Here's the first email I received from Roger at Leda after enquiring about my rebuild plans:


That seal looks to be a bespoke part made especially for the damper manufacturer. We call them 'flying saucer' seals as that is what this type of seal resembles. They were common fitment in 1950's and 1960's dampers, and their use faded in the 1970's when folks started to manufacture gas pressurised monotube dampers that required a different construction of high pressure seal. I would think that Peugeot Sport would be about the last to use this style of seal in dampers manufactured external to the factory for the 206 rally championship. These dampers were of the sealed unit type and were never designed to be serviced so the seals have never been available as a spare part, however we were asked to look into finding a way to extend the life of these dampers as they are so loved by latter day competitors in these semi-works cars.

As with many dampers that use this type of seal, the best option is nearly always to convert the damper to accept a modern multiple lip garter spring seal, which are readily available in various dimensions on-line from the likes of Simply Bearings or Bearing Boys, both based in Lancashire.

What we do is machine a new rod seal and guide bush holder and any spacers required, and fit this instead of the original stack of parts above the cylinder. In the case of the Peugeot Sport 206 rally dampers, we also braze a threaded adapter to the top of the carefully machined open damper body. This then allows fitment of a threaded top closure so internal access can be gained for service and repair into the future. We also usually machine new hard chromed damper rods as the originals are usually corroded, scored and generally not useable. I have attached some photos to give you a idea of the original parts and the replacements that allow fitment of modern available seals. In the internal component photo the obsolete bonded rubber and steel 'flying saucer' seal is the blue circular item on the top row.

There are rather a lot of photos attached, but hopefully you will get the idea. We use the same process to restore 1960's italian super car dampers that have a similar obsolete 'flying saucer' seal assembly and find this approach works very well with no complaints as yet!

I do hope this helps.

Regards,

Roger

[williamcorke]

I replied to Roger:
---
Hi Roger,

Thank you so much for taking the trouble to reply with all this information. Incredibly useful. It pretty much confirms what I already suspected.

I wrote to Record themselves, who referred me to a specialist supplier in Italy called Emmetec S.r.l. (www.emmetec.com). Looking through their website, I found a seal with the right ID and OD -

Clearly it doesn't have the reinforcing washers and raised central rubber like the flying saucer, but do you think it would seal my dampers? The next part down in the 'stack' provides the location for the rod with a guide bush, so that part of the unit's function is taken care of. I have been wondering if cutting down the old seals just below the top washer and mounting them in the stack above these new seals from Emmetec could provide additional protection for the new seal as well as keeping the original look... what do you think?

Best regards, and thanks again for taking the time.
--

And received the following:

Telescopic damper rod seals have to be energised somehow so the inside diameter grips the chrome rod to give a decent seal, they also have to correctly seal around their outside diameter, and have to either be fitted into a holder or have a solid thickness so as to give the correct internal stack height when the top is screwed tight.

Usually the seals grip the rod chrome by having stiffer rubber lips, or softer lips tightened by a garter spring fitted to the seal. The seal can also be forced against the rod chrome by internal pressure within the damper usually via gas pressurisation.

The outside diameter of the seal can be pressed into a holder to form a perfect seal, or it can be compressed against the damper body wall when the top closure is tightened. If the seal is fitted into a holder, the holder usually has an o-ring to seal it against the body wall.

The internal stack height is very important as the internal components are held parallel and solid within the damper body by tightening the top closure, which usually needs to be very tight on an unpressurised damper. In a pressurised damper, the top is usually held in place with an internal snap ring and the gas pressure holds the top tight against the snap ring to form a seal with the body. The top usually consists of a seal holder block fitted with an o-ring to seal the outside diameter.

The blue seal in the photo looks to use garter springs to seal the lips against the chrome rod, suggesting an unpressurised damper. The seal looks to have a substantial outside diameter, and the raised soft rubber outside edges suggest that these will be compressed against the body wall when the top closure is tightened to form a good seal. The rigid steel in the seal construction will hold the lips central and concentric to the rod with no eccentricity, and very importantly will provide a solid thickness to give the correct internal component stack height when the top closure is tightened.

As long as the proposed replacement seal can satisfy the above sealing, stack height and rigidity requirements, you should be OK.

Where replacement seals usually fall short is the solid thickness and the outside diameter sealing, and the use of sealing gunge rarely results in a long term seal.

[williamcorke]

Taking Roger's advice, I added a 1mm thick, 37mm diameter shim washer to make up the lost height of the replacement 'flying saucer' compared to the original part.

Photo of the 'stack' below.

So far so good, on reassembly the unit doesn't leak when worked up and down. In use? We'll see, eventually...

[williamcorke]

It also has to be said that all the people I met in the world of shock absorbers were helpful beyond the call of duty, especially Roger at Leda. A great experience, a bit learned and the old parts repaired at a cost of about 20 Euros for the seals, damper oil and postage (I was able to buy 2 seals, no minimum order).

[timdaw]

What a remarkably helpful chap Roger is!!! Most interesting and now I see why it's definitely worth saving these units, rather than replacing them. I hope they work well in use!