What It Does:

• Lets you reinstall the sealhead without damaging the edges of the U-Cup or O-ring
• Sized for 9mm shock shafts (Float X2 / DHX2 2016–2020)
• Compatible with MTB-Hydraulics Service Kit (includes O-ring sealhead upgrade)

Why Use This:

In many (A lot of rebuild shops change the locknut to a normal nut after the first rebuild) 2016–2020 Float X2 and DHX2 shocks, the piston is held in place with a thin locknut. Removing it often snaps the threaded tip of the shaft and unfortunately, if you're using the genuine Fox seal kit with a U-cup seal (Fox P/N 812-060-086), the sealhead must be installed from the piston side, which means you have no choice but to remove the piston and risk damaging the shaft.

That’s where this bullet tool comes in, it allows safe sealhead installation from the piston side without damaging the U-cup. It’s sanded to exactly 9.00 mm for a smooth fit and matches the shape of the official Fox 398-00-797 tool.

If the locknut breaks (or even if it doesn’t), we strongly recommend replacing it with a standard 1/4-28 thin profile nut and using red Loctite to secure it. The new nut doesn’t rely on the very tip of the shaft, so it’s safer and more robust long term.

• Only needed if you are installing the sealhead from the piston side (e.g. with U-cup seal)
• Not usable from the eyelet side, it’s the wrong shape for that

Note: If you use the MTB-Hydraulics seal kit, it replaces the U-cup with an O-ring. In that case, you can clamp the shaft in a 9mm shaft clamp, unscrew the eyelet, and press in the sealhead from the eyelet side. This method doesn’t require the bullet tool, but you’ll need a lot of SRAM Butter, and you’ll still have to press firmly to seat the seal.

Not the recomanded FOX procedure but I always do it and my shocks they never leak!

Installation Tip:
Use Slickoleum Grease, SRAM Butter, or Maxima Suspension Grease generously on the shaft and sealhead. The tool is a tight fit by design, grease helps avoid sticking and protects the seals.

⚠️ Warnings & Disclaimers:

• Only works with 9mm shock shafts, So only the DHX2 and Float X2 2016 to 2020.
• Not compatible with 2021+ DHX2 / Float X2 (they use different internals)
• This tool is made from plastic, less durable than the metal version and also less friction-less.

Helpful Links:

• How to Clamp Small Shafts
• Essential Tools for Any Rebuild
• Service Kit (MTB Hydraulics)