Always fully depressurize the air spring before removing the lowers. Air can remain trapped in the negative spring, deflate 15–20 psi at a time and pull gently on the lowers to equalize chambers. Do this before removing the wheel.

Fox 38 NA2:
This fork uses a removable airspring assembly. Follow the official Fox guide: Fox NA2 Manual

Fox 40:
You need a SPA-1 Pin Spanner (3mm) to remove the air piston. SPA-2 (2.3mm) may also work. Pin wrenches are not included since they are inexpensive/common tools.

• Fox 20wt Gold: air spring side (left leg)
• Fox 4wt Fluid: GRIP damper side (right leg)
• Slickoleum or SRAM Butter
• 60ml+ syringe with tubing (for oil volumes, see Fox chart)
• Soft mallet or block of wood
• 6-in-1 Top Cap Tool
• Heat source: torch, heat gun, or lighter (Loctite break)
• Red Loctite: for air shaft tip

• Dust Wiper Seal Press Tool (your selected size)
• Driver for lower-leg shafts
• 10mm Shaft Clamp for safe air-shaft clamping
• NA2 Bullet Tool (10mm Fox air shafts)

– GRIP dampers ingest lower-leg oil → always 4wt on damper side
– 20wt Gold on air spring side
– Non-GRIP forks: 20wt Gold on both sides
– Soak foam rings in oil before reinstalling
– Add 3ml of oil into the positive air chamber of the air piston

• Insert dust wipers slowly and straight, do not drive too deep
• Use a seal press with a center guide for perfect alignment
• Best removal tools: rounded/taped 32mm wrench (or 24mm)
• Never use anything sharp on the wipers
• Grease dust wipers + lower bushings generously with SRAM Butter
• Before reinstalling lowers, pressurize air spring to 10–15 psi to prevent vacuum
• Clamp air shaft 1–2cm under the tip, cleaned + wrapped with paper
• After removing air-shaft tip, slide out negative sealhead carefully
• Use NA2 bullet tool to reinstall sealhead smoothly (grease heavily)
• Don’t forget red Loctite when reinstalling the air-shaft tip