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Discussion Starter · #1 ·
A little while I made myself a bit of a custom CCDB coil shock by using the head assembly off a CCDB Air shock with climb switch. Everything worked and fit together well.

My first ride on this shock started out okay. The climb was fine, damping was solid and all adjusters worked including the climb switch. At the trail head of a short downhill trail, things were still good. But I noticed at the bottom of that trail, the shock was leaking. It leaked enough to get oil inside the spring and on the frame. I got that swishing sound so I knew I lost a decent amount of oil. I thought for sure it was the seal head o-ring because that's where all the oil was coming from. So it seems like it only started leaking when I started riding hard, not before and not while the bike was in the basement at my place.

I swapped that o-ring out, put her back together and went on a ride today. Same thing happened.

So I don't know why or how it's leaking. With measuring calipers, I checked to make sure I didn't slightly crush the shock body while using the vise clamps to swap head assemblies - it seems fine.

Thoughts?
 

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Discussion Starter · #4 ·
What size o ring did you use and what pressure did you charge the ifp to?
Not sure on size but I'll measure once I pull it apart again. I used a backup oring from a spare CCDB Air seal head that was still in good condition. I replaced the IFP with the bladder kit but regardless, I charged it to 140psi.
 

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Discussion Starter · #5 · (Edited)
Three possibilities really.

1. O-ring keeps getting damaged on assembly.


Possible although I had rebuilt my CCDB Air a few times and never had a problem.

2. Sealing surfaces are cactus (australian term)

I have a bad feeling this is the issue.

3. Wrong size o-ring.

Like I mentioned just above, I'll double check although I did pull the o-ring off the seal head from my other shock that worked fine. I wonder if there's a way to get a slightly thicker o-ring in there in case the surfaces are scratched.

Also, I'm assuming that oil is only leaking on the descents because that's when oil is being cycled through the shock at higher rates and pressure correct?
 

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I've done this mod too.

I noticed I was getting a leak where the shock screws in to the head.
I drowned it in oil resistant loctite, been fine since.

If you can't fix it, bodge it =)
 
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Three possibilities really.

1. O-ring keeps getting damaged on assembly.


Possible although I had rebuilt my CCDB Air a few times and never had a problem.

2. Sealing surfaces are cactus (australian term)

I have a bad feeling this is the issue.

3. Wrong size o-ring.

Like I mentioned just above, I'll double check although I did pull the o-ring off the seal head from my other shock that worked fine. I wonder if there's a way to get a slightly thicker o-ring in there in case the surfaces are scratched.

Also, I'm assuming that oil is only leaking on the descents because that's when oil is being cycled through the shock at higher rates and pressure correct?
If an o-ring is the right size, good condition and the surfaces are good it'll hold thousands of psi.
 

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Also, I'm assuming that oil is only leaking on the descents because that's when oil is being cycled through the shock at higher rates and pressure correct?
Yeah high speed/end stroke rebound has the highest pressures/force on the seal head so for some reason it isn’t sealing properly.

Take some careful measurements of the oring groove OD and damper body ID, the the o-ring CS to make sure you’re getting enough squeeze
 
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