Suspension: Koni strut servicing

I've seen similar design Konis but not for the X application. Interesting that yours is that style. :)

For any of the lip seals you might get lucky and find a generic one that can work, even though it isn't quite the same design as the original Koni one. Take all of the critical measurements along with your parts to a major seal supplier and see what they can find.
 
I also have Konis with this top

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I dismantled the top of the ones I'm rebuilding and all the parts look like this

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This is similar to the Lotus example. There are three rubber washers that measure 36mm o.d. x 20mm i.d. x 3mm thick. They are separated by the red fibre washers. On top of those there's the brass washer, two spring washers, a steel washer and the brass nut. The rod wiper seal goes between these last two, and may more pliable after soaking for week, but I have no way to quantify that.

The piston is 19.75mm o.d. and the rubber washes are 20.0mm i.d. so sealing is achieved by crush of the stack.
 
Hey @Dr.Jeff - amongst the pallets of parts that came with the group of cars/shells I picked up, are a pair of Koni struts exactly as you started this excellent thread with. The rebuild/parts situation in Australia is pretty much as is described for the US and I will be following your example in due course!
 
Steve Thomas said:
Hey @Dr.Jeff - amongst the pallets of parts that came with the group of cars/shells I picked up, are a pair of Koni struts exactly as you started this excellent thread with. The rebuild/parts situation in Australia is pretty much as is described for the US and I will be following your example in due course!
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The only difficult part is the main shaft seal. It is propriarity and no substitutes exist. Getting a real Koni seal can only be done through the approved service facility (I believe there is still only one such place in the US), and they won't sell you just the seal...you must pay them to completely rebuild the unit (which is more expensive than buying new struts). So be careful with that seal as you work on them. ;)
 
I have 4 Konis that I have to rebuild and in Australia there's only one rebuilder.
Same story, "send them to us and we will do them" but we won't tell you how much.
So I will be VERY interested in a source for the seals.
 
Hybridfiat said:
I have 4 Konis that I have to rebuild and in Australia there's only one rebuilder.
Same story, "send them to us and we will do them" but we won't tell you how much.
So I will be VERY interested in a source for the seals.
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Hopefully there is a source for the main seals there in Australia. There isn't in the USA. Even my personal contact at Koni said he could not help me. Apparently they have sublet ALL service and parts activities/inventory to the sole rebuilder in the US.

I asked my general seal supplier if there was any possibility of finding something close enough to replace the propriarity Koni main seal. We found one with the correct basic dimensions but it was questionable if the rest of it would fit correctly. On my Koni's the main seals were still good so I did not want to ruin them (which removal will do) to test the replacements. However if your seals are definitely destroyed already, then take everything to a major seal supplier over there and see if they can find something that might work. You really don't have much to lose by trying; worst case scenario you have to pay the price to have yours rebuilt anyway. The seal suppliers here tend to cater to the heavy equipment industry that uses a lot of hydraulic rams and such on their equipment. But they carry an amazing array of every type of seal imaginable.
 
and the latest car I acquired has a full set of Koni. Sadly, the rear pair have had KYB inserts fitted in place of the original Koni guts. But the fronts are complete. I expect to start the rebuild of these plus the pair from the other car next month.
 
Dr.Jeff said:
Hopefully there is a source for the main seals there in Australia.
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yeah, nah cos Koni. But I am thinking printed as clearly, we are on our own. Lots of duro choices in the polyurethanes and plenty other decent materials now too. Only a twinkle in my eye at present but I reckon!
 
Those aftermarket from back in the day Koni replacement for oem damper/struts are limited to essentially stock spring rates and similar..
With stock or close to stock spring rates, there is not a lot to gain by refurbing decades old Koni dampers unless there is hard need to preserve originality..

Once the stock spring rates are significantly altered, those oem replacement Koni damper/struts are not gonna work... at all.

The FAR better solution is to get or make a set of strut housings that can fit Koni 8610 single adjust or 8611 double adjust damper inserts. These are current Koni product, supported and parts/alterations to damp rates compression/rebound can be had...

Better dampers are made by folks like Penske, Ohlins and others.. with all the modern perks..

Root of this question and need, what are the chassis/suspension/driver goals?

The name "Koni" is not automatically best..
Bernice
 
The nice thing about those Koni units is they are easy to rebuild and revalve/retune if you want to run stiffer springs. Perhaps not the ultimate race item, but excellent for street applications. ;)
 
Dr.Jeff said:
The nice thing about those Koni units is they are easy to rebuild and revalve/retune if you want to run stiffer springs. Perhaps not the ultimate race item, but excellent for street applications. ;)
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Those vintage special Koni seals are not so easy to get.. via previous discussions..

Bernice
 
Rupunzell said:
The name "Koni" is not automatically best.
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All understood and agreed. As you suggest - context is all. I have a qty of period Koni and am restoring cars to street = rebuild those old style Koni. I am keeping the stock spring rates as I personally find them a good compromise once again in context of street use on our frequently appalling roads. Koni, unlike Michelin or Pirelli, cares nothing for their history. Yeah, they brag about it but activly make it harder for people to use older product. No way would I be buying new Koni product. They won't notice or care but it is a small form of protest that warms my heart.

I also regard the whole "rebuildable" marketing guff as just that simply becasue Koni go out of their way to PREVENT rebuilding... But there remains some mystique to the brand and just as I will be installing period [ish] audio and tyres, I will keep the Koni if I can.
 
As it has been discussed previously in this thread, getting Konis (from any era) rebuilt/revalved/custom tuned is not an issue. However getting the proprietary parts from Koni to do it yourself is (which was not the case in the past). Therefore you cannot do certain work yourself; you either have to get it done by a Koni authorized service facility, or don't replace the proprietary parts. The good news is only a couple of the parts are proprietary. The biggest issue is the large main seal at the top of the body (where the shaft enters and the gland nut fits), which IS proprietary. It is more prone to wear and leaking and it is the only seal that is specially designed for these units - all of the others are generic. At one time you could buy replacement disks to revalve them yourself but I haven't researched to see it that is still possible (without having the authorized center do the work). I believe the disks used in some Konis are interchangeable with some other shocks. And their performance can be altered with small modifications, rearranging their order, or other tricks if you know how (a good friend of mine ran one of the country's largest motorcycle shock servicing facilities for decades and knows all the tricks).

Additionally there is another way to change the performance properties of Konis without revalving. If you are seeking a general change in their dampening rates (equally for both compression and rebound), then you can change the viscosity of the fluid inside. Koni themselves do this in addition to changing the valve disks. And motorcycle fork oil is the same stuff used so there's a wide variety of viscosities readily available.

Plus don't forget, Konis are externally adjustable. And the adjustment has a rather profound effect on their dampening. Add this to the above comments on oil viscosity and there is a lot you can achieve without sending them out to the service center (as long as the top main seal isn't leaking). By the way, there is only one Koni authorized service center in the USA now. All others are no longer backed by Koni and must rely on their existing inventory of service parts. That has driven up the prices charged by the company that Koni does support.
 
Dr.Jeff said:
The nice thing about those Koni units is they are easy to rebuild and revalve/retune if you want to run stiffer springs. Perhaps not the ultimate race item, but excellent for street applications. ;)
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Maybe Henk in Holland can open the back door of the factory to access the needed proprietary spares.
 
Steve Thomas said:
plus they won't sell parts [same in Australia] - how does that sit with the "right to repair" law that I though was either in place or coming in the US?
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That law mostly has to do with manufacturers releasing proprietary software needed to communicate with diagnostic ports. Allowing independent service facilities to diagnose and repair those vehicles.
 
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