2016 40mm FLOAT NA2 Rebuild
- 803-00-964 Seal Kit: 40 FLOAT NA2 Rebuild
- 398-00-657 Tooling: Bullet, Sealhead To Shaft, FLOAT NA 2
- 398-00-681 2002-017 32 Damper-side and ALL 32-34-36-40 Spring-side Removal Tool
- 398-00-682 2005-017 34-36-40 Damper-side Removal Tool
- 398-00-705 Tooling: Fork Topcap Socket, 32mm, 3/8 Drive
- 803-01-324 Kit: Tooling: 2019 Clamps, Grip Damper, Body and Shaft
The following procedure guides you through the rebuild of the FLOAT NA2 air spring found in 2016+ 40mm forks.
WARNING: FOX products should be serviced by a trained bicycle service technician, in accordance with FOX specifications. If you have any doubt whether or not you can properly service your FOX product, then DO NOT attempt it. Improperly serviced products can fail, causing the rider to lose control resulting in SERIOUS INJURY OR DEATH.
WARNING: Never attempt to modify air volume spacers or air shaft assemblies, as this can damage your fork causing a loss of control of the bicycle leading to SERIOUS INJURY or DEATH.
WARNING: FOX suspension products contain pressurized nitrogen, air, oil, or all 3. Suspension misuse can cause property damage, SERIOUS INJURY OR DEATH. DO NOT puncture, incinerate or crush any portion of a FOX suspension product. DO NOT attempt to disassemble any portion of a FOX suspension product, unless expressly instructed to do so by the applicable FOX technical documentation, and then ONLY while strictly adhering to all FOX instructions and warnings in that instance.
WARNING: Modification, improper service, or use of aftermarket replacement parts with FOX forks and shocks may cause the product to malfunction, resulting in SERIOUS INJURY OR DEATH. DO NOT modify any part of a fork or shock, including the fork brace (lower leg cross brace), crown, steerer, upper and lower leg tubes, or internal parts, except as instructed herein. Any unauthorized modification may void the warranty, and may cause failure or the fork or shock, resulting in SERIOUS INJURY OR DEATH.
Loosen the 5mm hex bolt (counter-clockwise) on the air side of the upper crown. With a chamfer-less 6-point 32mm socket, unthread the topcap assembly completely. Pull straight up to remove the entire topcap assembly from the left side stanchion tube. Some upward force might be needed to overcome the friction of the stock air volume spacers.
With the fork slightly inverted (the bottom of the fork up past horizontal), remove the black cover, then use a 2mm hex wrench to remove the red rebound knob.
Use a 10mm socket to unthread and remove the air side bottom nut. Remove and discard the original crushwasher.
Use a 15mm socket to remove the damper side bottom nut. Make sure to remove and discard the orginal crushwasher which may be stuck to the bottom nut.
Use Damper Removal Tools 398-00-681 and 398-00-682 to dislodge the shafts from the lowers. Make sure that you have approximately half of the available threads engaged with your tool before striking with your mallet. Remove the damper removal tools, then bring the fork upright over an oil basin to drain. After oil stops draining from the lowers, pull the lowers off of the upper tubes and set them aside.
Remove the retaining ring from the bottom of the air side upper tube. 40mm forks use a single wound Hoopster style retaining ring.
Never remove the retaining ring from the middle of the shaft as the edges of the ring may scratch the shaft. Always remove the retaining ring from the shaft by pulling it past the end of the shaft.
Thread the damper removal tool (PN: 398-00-681) onto the air shaft and pull out from the upper tube to remove the air shaft assembly.
Wipe grease off of the air shaft assembly to make it easier to handle. Position your pin spanner with 3mm pins in the underside of the piston base, then clamp the shaft in your 10mm shaft clamps (PN: 803-01-324), resting the pin spanner on top of the shaft clamps as shown.
Hold the pin spanner stationary and unthread the piston (counter-clockwise) with a 10mm socket. Lift the dome shaped pistion up off of the pistion base to remove. Remove the gray piston band and set it aside.
Remove the Q-ring from the piston and replace it with a new greased one from the kit. Reinstall the gray piston band.
Reinstall the domed piston onto the piston base. Hold the pin spanner stationary while tightening the piston to 120 in-lb (13.6 Nm) with a 10mm socket.
Slide the neg plate toward the base stud, leaving enough space to access the base stud wrench flats. Clean the shaft with Isopropyl alcohol then clamp it in your 10mm shaft clamps (PN: 803-01-324). Remove and discard the o-ring from the base stud.
Carefully apply heat to the shaft at the base stud with a propane torch for 5-10 seconds to break down the Loctite. Unthread the base stud counter-clockwise with a 12mm wrench, then lift up to remove. Lift up on the neg plate to remove it from the shaft.
Insert a 4mm hex wrench through the holes in the neg plate tube and hold it securely. Carefully use your 6-point chamfer-less 32mm socket while holding the socket onto the neg plate wrench flats to unthread (counter-clockwise) the neg plate from the neg plate tube.
Remove the external o-ring and replace it with a new greased one from the kit. Remove the two seals from the inside of the neg plate.
Install a new greased Q-ring from the kit into the uppermost seal groove. Insert the seal through the bushing and guide it into position with a blunt tool like a 2mm hex wrench or similar. Make sure the Q-ring is fully seated in it's groove and not twisted.
Install a new greased u-cup seal from the kit into the lower seal groove, making sure to orient the u-cup lip down as shown.
Reintall the neg plate into the neg plate tube. Tighten to 120 in-lb (13.6 Nm) with your 6-point chamfer-less 32mm socket while holding the neg plate tube with your 4mm hex wrench.
Insert the FLOAT NA2 bullet tool (PN: 398-00-657) into the shaft, then coat it with a thin film of Slick Honey. Reinstall the neg plate with it's flat side down. Remove the bullet tool.
Apply 1-2 drops of red Loctite 262 to the threads inside the shaft. Insert the base stud and thread it in clockwise, tightening to 50 in-lb (5.7 Nm) torque with a 12mm crow's foot. Install a new greased o-ring from the kit onto the base stud.
Apply a thin film of Slick Honey to the inside of the upper tube. Apply a thick film of Slick Honey to the air shaft assembly in the areas of the piston, neg plate, and shaft above the neg plate.
Insert the air shaft assembly into the end of the upper tube. Push the air shaft assembly into the upper tube far enough to allow you to start the neg plate into the upper tube. Push the shaft into the upper tube to pull the neg plate into its installed position.
Replace the retaining ring making sure it is fully seated in its groove by pulling on the air shaft.
Inject 6cc of FOX 20wt. Gold oil into the main air chamber through the top of the upper tube. Reinstall the topcap into the fork crown and tighten clockwise to 220 in-lb (24.8 Nm) torque with your 6-point chamfer-less 32mm socket. Tighten (clockwise) the 5mm hex bolt on the air side of the upper crown to 65 in-lb (7.34 Nm).
Add air pressure to your desired setting using a FOX high pressure pump. See the Setting Fork Air Pressure section for more information. Reinstall the blue air cap.
Install the Lower Leg Assembly onto the upper tubes. Inject 50cc of FOX 20wt. Gold oil into the damper side lower leg. Inject 35cc of FOX 20wt. Gold oil into the air side lower leg. Clean any oil off of the exposed shaft threads.
Install a new crushwasher on each side followed by the appropriate bottom nut. Torque both bottom nuts to 50in-lb (5.7 Nm).
Use a 2mm hex wrench to install the red rebound knob. Make sure that the set screw lines up with the depression in the rebound adjuster shaft. Reinstall the black rebound knob cover. Clean the exterior of your fork.
After assembly you must compress the fork 3-5mm very slowly until you feel the chamber pressures equalize.