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I just saw the video for this. April linked me. Whole crap. Makes me want support Mitsu More and order these OEM.

But in future I absolute love to see this project.
Serviceable Mod or just new shell to house it.
 

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What if, instead of crimping the upper seal, you cut threads into the outside of the strut and screwed on a collar to hold the seal in?

That would solve the seal issue, but not the pressurized gas/oil issue.
 

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We need to find a good rebuild process.

I have an idea for getting around the crimping, its to machine a ring that screws on with the seal and tap/die the strut to accept the new ring.

We need to solve pressurizing the cylinders.

There was some talk in this thread about welding on a bung to pressurize from? Has this been done?
 

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Discussion Starter #50
Any Shop that would have experience in building/modifying/maintaining Racecars.

I learned how to do it while working at a Porsche shop.
 

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DG (Dennis Grant) hasn't been online in couple years, if he doesn't respond via PM, perhaps you can ask him via his website if he's able to recommend a shop to do strut rebuilds, he created the video of the ecs strut teardown too.

Far North Racing - The Stealth Site
 

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To bad no one works at or knows someone who works for KYB. I know they make the non ECS struts for Mitsubishi, did they also make the ECS? They should still have all the info on how to make new stock ones.
 

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That tear down video of an ECS strut was pretty informative. Basically, the mechanics/electronics inside the strut seem to be pretty simple and robust.

Now, there is nothing you can do about a worn out strut... but what about one that just stops switching, causing an ECS fault? When an electric motor sits unused, it can develop a tendency to stick... I have seen this countless times. Has anyone limped around with a bad starter by smacking it with a 2x4? Small, low power motors have a very small torque capability during acceleration, so any unexpected load can cause the current draw to exceed the controller limit and the fault is set.

I guess I am wondering if anyone has ever tried to revive a dead-switching strut by momentarily applying extra current? Or by gently tapping the strut shaft with a small ball-peen hammer to give a little jolt the motor?

I guess you could still have a bad rotary switch array (or a dead motor/open windings), but the tear down didn't expose the switching, so it's hard to tell what that switch even looks like. Still, though... I bet just giving that motor a little spin could clear things up. Too bad you have to destroy the shock to get to it.
 

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Basically, the mechanics/electronics inside the strut seem to be pretty simple and robust.

Now, there is nothing you can do about a worn out strut... but what about one that just stops switching, causing an ECS fault? When an electric motor sits unused, it can develop a tendency to stick... I have seen this countless times. Has anyone limped around with a bad starter by smacking it with a 2x4? Small, low power motors have a very small torque capability during acceleration, so any unexpected load can cause the current draw to exceed the controller limit and the fault is set.

I guess I am wondering if anyone has ever tried to revive a dead-switching strut by momentarily applying extra current? Or by gently tapping the strut shaft with a small ball-peen hammer to give a little jolt the motor?

I guess you could still have a bad rotary switch array (or a dead motor/open windings), but the tear down didn't expose the switching, so it's hard to tell what that switch even looks like. Still, though... I bet just giving that motor a little spin could clear things up. Too bad you have to destroy the shock to get to it.


So you are exactly right to bring up that attempting to refurb a 3k ECS strut would involve more than just fixing the seals & refilling.

And for a strut that is failing electrically, I really don't think this would work as solution " I bet just giving that motor a little spin could clear things up."

I've seen three common failure modes of the electrical portions of a 3k strut:

(1) the motor actuator get sluggish or ceases to work. This could be from a failure in the motor windings or the bearings seize up.
(2) The positional switch contacts get worn out and start giving false readings
(3) the electrical connections / internal ribbon cable leading from the top strut get broken.

Refurbing and completely Fixing (1) & (2) would be difficult. The internals would need to be completely torn down and repaired similar to a starter motor repair. New windings, New contacts etc etc.

here's a tech manual pic of the switches setup. It's sliding contact rotary encoder kinda deal:

 

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Could work... not would work. ;) Great info - was this in the car's service manual? If so, I am surprised that such detail of a component would be included. I can see that switch wearing out, or the contacts just not making a good connection. Or even those little gears striping. Either way - DOA.

I am sure you're right. One of mine stopped working after sitting for a long time. It's just too bad.
 

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I was actually lucky enough to get the very last brand new front ECS strut available in the country for my '94 VR-4 a few months back. I then found a JDM pair on Ebay and purchased those just in case but I couldn't agree more that something needs to be done or some solution found in order to keep our vehicles running as they were intended to. Does anyone know if in fact it definitively was KYB who manufactured the ECS struts? If so, I'd be more than happy and willing to reach out to them and see what if anything they know or can do or whatever so long as it's helpful.
 

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Any updates on this, I replaced both of my cars suspension and stored the ECS struts hoping that we can find out how to rebuild them, I have been researching about that kind of DIY rebuild from other platforms and I know that is not as easy as just refill and good to go, so I imagined something like this, remove the collar, cut the crimped tabs at the seal level:




Then, machine the tube or add another collar to allow a gland nut





either way, this in order to have a way to replace the seal and keep it in place after the rebuild.

More info:
https://www.vorshlag.com/forums/forum/board-rules-and-announcements/announcements/6883-vorshlag-customized-e30-strut-housings-for-asts?t=8044

We can somehow source the seal or even better, get a more common one that fits the shaft and custom build the gland nut to accept it.

For the refilling part, if we can open the strut like that, the oil is not a big deal but the nitrogen part, we can weld a npt bung and put a schrader valve there, those are originally filled with liquid nitrogen and I don't know how to get that one easily





I ordered a a set of npt weld bungs and the schrader valve, gonna try to refill a set knowing that it will slowly leak since the seal is bad in the first place, if we find someone that can work the housing and adapt a gland nut I think it's very feasible to rebuild (assuming no dead switches/servo).
 

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I'm pretty new to the community here, but I've been looking at the shocks and think i've come up with a solution to rebuild them. Most are looking at it backwards.. put the nitrogen in the shock first, then put the oil.. lemme explain.

A lot of shocks today use nitrogen in a wear proof bag. you put that into the shock and then fill with oil, remove any air, and cap it. Then you pump in oil to pressurize it to your desired rate.

A side effect is an increase in the performance of the shock as the nitrogen won't be mixing with the oil. And as the shocks are twin tube, it doesn't matter where the bag is as it is never near the piston.

https://tbcfindlay.com/knowledge-center/ makes the bags. I know QA1 sells them for the circle track shocks https://www.ebay.ca/itm/QA1-9052-121-Bag-Gas-Nitrogen-81-5-Cc-137Mm-X-241Mm-5-40-X-9-5/292003386544

Assuming you can find the correct seals, should be trivial. Just need to weld a hydraulic fitting to allow you to pump oil in. Additionally if you wanted to really increase the performance for road course or rally use, you could connect the hydraulic fitting to a remote reservoir to aid in fluid cooling.

Just need to uncrimp the seal.. i've got ideas for that too.. assuming the motors still work in the shock, we should be able to revive them, rather safely.
 

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DaveU, really like your idea. I've thought about the possibility of rebuilding these shocks because I'm a farm boy and in my life anything is rebuild-able. I'm not a machinist but I have a cousin who is and has done some incredible stuff. I was going to ask him about it some time. 3s's are rare around here so I have a real hard time trying to find old ECS struts anywhere. Good luck, hope you can make something work.
 
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