Fat Cat leakage
#1
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No our weight challenged cat doesn't have seepage but my FCM does. ![rofl](https://www.miataturbo.net/images/smilies/rofl1.gif)
Noticed some drips on the floor sometime around May. I thought the leakage was coming from the shaft seal as there was a small puddle on top of the wiper. I cleaned it up and checked my....errr...the shaft for any obvious nicks/scratches and couldn't find anything. (that's what she...) After cleaning, I function tested the shock and couldn't get ANY leakage.
I put everything back together, drove it for months and absolutely no leakage. Last week I noticed some more drips. Took it off again and this time no puddle on the wiper. All of the leakage is contained in the adjustable spring collar (the small gap on the top side of the shocks c-clip). There is an o ring inside that keeps the shock oil from leaking down the backside of the collar.
![](https://www.miataturbo.net/attachments/suspension-brakes-drivetrain-49/124504-fat-cat-leakage-20140926_105658_resized_zpse1a6bb71.jpg?dateline=1411745088)
Possible leak spot above, ^^^^^ where the hole was drilled for disassembly?
![](https://www.miataturbo.net/attachments/suspension-brakes-drivetrain-49/124505-fat-cat-leakage-20140926_105714_resized_zps57ee78dd.jpg?dateline=1411745088)
Question two.....the rear bumpstop (on same shock), is awfully short (20mm). The shock internals bottom out 1/2" before the bump touches. This can't be correct?
![rofl](https://www.miataturbo.net/images/smilies/rofl1.gif)
Noticed some drips on the floor sometime around May. I thought the leakage was coming from the shaft seal as there was a small puddle on top of the wiper. I cleaned it up and checked my....errr...the shaft for any obvious nicks/scratches and couldn't find anything. (that's what she...) After cleaning, I function tested the shock and couldn't get ANY leakage.
I put everything back together, drove it for months and absolutely no leakage. Last week I noticed some more drips. Took it off again and this time no puddle on the wiper. All of the leakage is contained in the adjustable spring collar (the small gap on the top side of the shocks c-clip). There is an o ring inside that keeps the shock oil from leaking down the backside of the collar.
![](https://www.miataturbo.net/attachments/suspension-brakes-drivetrain-49/124504-fat-cat-leakage-20140926_105658_resized_zpse1a6bb71.jpg?dateline=1411745088)
Possible leak spot above, ^^^^^ where the hole was drilled for disassembly?
![](https://www.miataturbo.net/attachments/suspension-brakes-drivetrain-49/124505-fat-cat-leakage-20140926_105714_resized_zps57ee78dd.jpg?dateline=1411745088)
Question two.....the rear bumpstop (on same shock), is awfully short (20mm). The shock internals bottom out 1/2" before the bump touches. This can't be correct?
Last edited by stratosteve; 09-26-2014 at 02:18 PM.
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I took the other side off to compare bumpstops and travel. Same bump except this one contacts the bump before internal contact. AND........The first inch of shaft movement, there is barely any resistance and then normal shock feel the rest of the way. I r disappoint.
I have a theory on the first one. If it lost enough shock oil, then the diaphragm separating the gas chamber from oil will move toward the piston causing less travel?
I am so excited to have to drop hundreds more greenies on a barely used set of expensive FCM's.
I have a theory on the first one. If it lost enough shock oil, then the diaphragm separating the gas chamber from oil will move toward the piston causing less travel?
I am so excited to have to drop hundreds more greenies on a barely used set of expensive FCM's.
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I contacted Sheikh back in May when I first discovered the leak.
I have boxed both the rears up and they are on the way back.
What pisses me off is how they were marketed as the best thing since sliced bread when I purchased them. During our May conversation, I got the "oh the seals in the Shrader valves go bad and they will leak." So now the marketing is "that was an inferior design and we build them like the OEM's do." Well, had I known that I would have to spend another chunk of change a few years and only few thousand miles later..... to correct a flaw I was not even remotely aware of????
I have boxed both the rears up and they are on the way back.
What pisses me off is how they were marketed as the best thing since sliced bread when I purchased them. During our May conversation, I got the "oh the seals in the Shrader valves go bad and they will leak." So now the marketing is "that was an inferior design and we build them like the OEM's do." Well, had I known that I would have to spend another chunk of change a few years and only few thousand miles later..... to correct a flaw I was not even remotely aware of????
Last edited by stratosteve; 09-28-2014 at 02:12 PM.
#9
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In our market at work, every improvement we make results in customers wanting all previous product upgraded. The end result is we become hesitant to make improvements. Why was it not already perfect? Yet all customers request continuous improvement.
Though I feel your pain, all products evolve as companies learn new things, including when something turns out to be less robust than predicted.
Though I feel your pain, all products evolve as companies learn new things, including when something turns out to be less robust than predicted.
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And in my particular case, my 04 has 19k on it. I believe these FCM's have maybe 4k on them. Not tracked, not ax'd and spends most of its time sleeping in the garage.
Do I believe I should get an upgrade for free........absolutely not. Do I believe they should have lasted more than a few years/few thousand miles.....absolutely. I do believe the first one should be fixed at a reduced rate. That hole was drilled slightly lower than the other. I don't know if ultimately that is the reason for the leak but it makes sense.
Do I believe I should get an upgrade for free........absolutely not. Do I believe they should have lasted more than a few years/few thousand miles.....absolutely. I do believe the first one should be fixed at a reduced rate. That hole was drilled slightly lower than the other. I don't know if ultimately that is the reason for the leak but it makes sense.
#11
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Reduced rate, sure. I'm not privy to the arrangements you and FCM have come to, nor do I think I should be. Just talking about reasonable expectations. You will notice that I also have a set of their coil-overs. I, too, will be disappointed if I don't get MANY more than 4K miles from them.
Best of luck.
Best of luck.
Last edited by DNMakinson; 09-29-2014 at 12:59 PM. Reason: Tense correction
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Update......I received them on Friday after repairs. I nearly shat myself because I thought it was only a two week turnaround. Wow, I said.....Two weeks for revalved bilsteins.......bernie? But I was wrong, it was 3 weeks.
I installed them that evening and a quick test drive netted positive results. No more thumping from the rear. They are much better in working condition.
It could just be me justifying spending money, but they seem to work better than when I first got them.
I installed them that evening and a quick test drive netted positive results. No more thumping from the rear. They are much better in working condition.
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Sounds like you are satisfied.
Did they actually change the tuning as well as repair?
Do they still have the schraeder valves. Do you expect that these will hold this time? Yes, it's me again... I suppose I really do care.
Did they actually change the tuning as well as repair?
Do they still have the schraeder valves. Do you expect that these will hold this time? Yes, it's me again... I suppose I really do care.
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No changes to tuning. I didn't ask but I got the impression they do a before and after dyno.
No Schrader valves. The service holes were welded closed and the Shrader valves were replaced with an Allen headed plug. It appears there is some sort of sealant or epoxy on the plug threads. Not the greatest job of painting the welded area, so I painted that area myself. Not a big deal because it is covered by the sleeve.
I am considering getting the fronts done now. But I may have them tuned for heavier springs and replace my rb sway with stocker.
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