Im rebuilding my kyb shock. All went smooth until I try to push the shaft/piston into the shock body. The rebound needle is stuck completely shut and won't allow the piston to go in through the fluid. The clicker is opened all the way, and I can use a small screwdriver in the end of the shaft to press the needle open, but it pushes itself right back shut. It feels like there is some sort of hydraulic pressure keeping it shut. This is my first time rebuilding a shock so I have no idea how to remedy this, and no one anywhere seems to have this problem that I can find. Already pretty irritated after I sprayed an entire bottle of shock fluid all over the garage roof trying to push it in wondering why it wasn't working. Any input on this would be greatly appreciated
If you have the tools, you can remove the clevis and check out the parts.
It's a pretty simple setup.
There's a rod with the steel needle tip and there's a bushing at the bottom of the shaft with an o-ring and a plastic backer-ring.
You can push the rod out of the shock shaft after you remove the clevis.
It's possible that your o-ring is bad and the clevis is full of oil.
If there's oil in the clevis, it will hydraulically lock out the rod.
If that's the case, pop the o-ring out of the shaft with a dental pick to inspect it.
Check the rod for damage.
Use some suspension grease on a new o-ring and push it in place inside the shock shaft.
You need to use a flashlight to check that the new o-ring popped into the groove all the way around before installing the rod.
Here are some photos of an older 16mm KYB shaft and a recent 18mm shaft.
The clevis and o-ring close-up photos are the 18mm parts.
I’ve run into this problem before. Try banging the clevis end vertically on a block of wood. This has always worked for me.
Yep had the same issue as well a while back and reached out to a suspension tech, he had me push the needle down and run a small piece of safety wire through the holes on the shaft to hold it in place open until bleeding was done make sure the wire was long enough to pull out when installed. Worked like a charm and functioned fine once buttoned up and re-charged. I think I let the N2 out prior to backing clickers off or something and stated that could cause the issue… I think…was years ago but the wire trick worked just be gentle.
Wow! Thank you for the excellent reply. Is there a trick to getting the clevis off of the rod or does it just thread off the end after you loosen the nut?
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I was able to get it to stay down just by loosening the clevis nut. Doing that seemed to relieve the pressure somehow and it stayed down. After looking at the pictures of them apart though, I'm not sure how that could have worked. How long does it take for that o ring to go bad? I bought this bike new and it has about 90 hrs on the shock
No problem. Hopefully you can solve your issue.
There will be thread locking compound (like Loc-Tite) on the threads...
The way suspension shops remove a clevis is to clamp the rod in a vise using a special set of round soft-jaws sized for the rod.
If you have flat jaws in your vise (not serrated) you can hold the aluminum clevis and loosen the lock nut.
In a pinch, the method below works to remove the rod (it's better to use the soft jaws).
Run the clevis lock-nut up toward the piston until it stops.
Use a 17mm wrench on the piston nut while also using a 22mm or 24mm wrench (16mm or 18mm rod) to loosen the rod from the clevis.
KYB rods don't have much torque after the lock nut is backed off of the clevis.
It will have friction all the way out, due to the thread locker.
Use a bronze wire brush and some solvent to clean the thread locker out of the threads on the rod.
When you re-install the clevis, you need the lock nut all the way up the threads toward the piston.
Make sure the rebound adjuster screw is backed all the way out (counterclockwise).
Loc-Tite 242 (blue / removable) on the rod threads is a good idea. Don't let any drip into the clevis.
Thread the rod into the clevis until it is fully bottomed out. You can apply a little torque using the 17mm nut at the piston end of the rod.
Torque the clevis lock nut last, it keeps the rod tight and in place.
Thank you very much, you have been an enormous help. Glad to have this info. Every shock rebuild tutorial I watched never mentioned anything about inspecting the rebound rod/adjuster function, just to turn it all the way out. Seems like a pretty integral part 😒
No problem.
It's not really part of a normal shock service.
It's rare that the clevis ever needs to be removed for any reason.
Try blowing compressed air through this hole. Then clean/spray it with suspension cleaner or contact cleaner. Usually solves the problem when that happens.
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