BOMBER Z2 Full Rebuild
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.
NOTE: This procedure guides you through the full rebuild of the BOMBER Z2 fork. While a non-remote version is shown, the procedure is identical for remote versions with the only difference being the installation and removal of the Topcap Interface Parts. BOMBER Z2 Remote Topcap Interface Part Installation can be found here: 2020 Grip Remote Topcap Interface Part Installation »
Use a 2mm hex wrench to unthread (counter-clockwise) the set screw in the black rebound knob. Remove the knob and set it aside.
Unthread and remove the bottom nuts by turning counter-clockwise with a 12mm socket. Z2 forks do not have crushwashers under the bottom nuts.
Use Damper Removal Tool 398-00-681 to dislodge both 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 tool, 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 black Air Cap by turning it counter-clockwise. Release the air pressure by depressing the air valve core with a blunt tool.
Unthread the air-side topcap assembly counter-clockwise with a 6-point chamfer-less 26mm socket (PN: 398-00-702). Replace the topcap o-ring with a new greased one from the kit then set aside in a clean area.
Remove the retaining ring from the bottom of the air-side upper tube. Use the damper removal tool (PN: 398-00-681) to pull the Air Shaft Assembly out of the bottom of the upper tube. Remove the tool from the Air Shaft Assembly.
Hold the Rail Compression Knob from turning while you unthread its screw counter-clockwise with a 2mm hex wrench. Set the knob and screw aside in a clean area.
Unthread the damper-side topcap assembly counter-clockwise with a 6-point chamfer-less 26mm socket. Lift the Topcap Assembly out of the upper tube. Pour out any damper oil from the upper tube.
Remove the retaining ring from the bottom of the damper-side upper tube.
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.
Pull the Damper Shaft Assembly out from the end of the upper tube. Set the Damper Shaft Assembly aside in a clean area.
Invert the Rail Topcap Assembly and carefully clamp it in your shaft clamps (PN: 803-00-830 shown but other 10mm shaft clamps will work). Unthread the Piston Nut counter-clockwise with an 8mm socket. Remove the Piston Nut and Check Spring.
Remove the Topcap Assembly from your shaft clamps. Unthread the Compression Needle counter-clockwise, then pull up to remove.
Replace the o-rings on the Topcap and Compression Needle with new greased ones from the kit. While a metal seal pick is shown pointing at the seals to be replaced, a plastic seal pick is recommended to prevent damage to the seal glands.
Dip the Compression Needle up to the threads in FOX 5wt. Teflon infused oil. Reinstall the Compression Needle into the Topcap by threading it in clockwise.
Invert the Rail Topcap Assembly and carefully clamp it in your shaft clamps (PN: 803-00-830 shown but other 10mm shaft clamps will work). Reinsert the Pin through the Shaft. Replace the o-ring inside the Preload Hat with a new greased one from the kit. Reinstall the Preload Hat onto the Shaft.
Clean and inspect the Compression Valving shims for any damage. Replace if necesarry. Orient the Compression Valving in its original order then reinstall onto the Compression Piston Stud.
Replace the U-cup seal on the Compression Piston with a new greased one from the kit. Make sure that the U-cup seal lip is oriented as shown.
Reinstall the Compression Piston onto the Piston Stud as shown. Reinstall the Check Shim on top of the Compression Piston.
Reinstall the Check Spring, then apply 1-2 drops of Red Loctite 263 to the Piston Nut threads. Reinstall the Piston Nut tightening clockwise to 16 in-lb (1.8 Nm) torque with an 8mm socket. Verify that the Check Shim is not pinched and can spin freely after Piston Nut tightening. Clean off any excess Locitite.
Replace the o-ring on the outside of the Sealhead as well as the Base Stud with new greased ones from the kit.
Replace the Quad-ring seal on the Air Piston, the o-ring on the outside of the Neg Plate Subassembly, and the o-ring on the Base Stud with new greased ones from the kit.
Clean the inside of the upper tubes with Isopropyl Alcohol then dry with a lint-free paper-towel.
Coat the Air Piston, Neg Plate Subassembly, and the air shaft between the two with a thin film of Slick Honey. Coat the first few inches of the inside of the air-side upper tube with a thin film of Slick Honey. Reinstall the Air Shaft Assembly into the bottom of the air-side upper tube.
Reinstall the Retaining Ring into the bottom of the Air-Side upper tube. Pull on the Air Shaft Assembly to verify that the Retaining Ring is fully seated.
With the fork upright, inject 3cc of FOX 20wt. gold oil into the Air-Side upper tube. Reinstall the Air-Side Topcap Assembly, tightening clockwise to 220 in-lb (24.8 Nm) torque with a 26mm 6-point chamfer-less socket.
The air spring must be fully extended before reinstalling the lower legs. Add air pressure to your desired setting using a FOX high pressure pump. Reinstall the black Air Cap.
Coat the Sealhead of the Damper Shaft Assembly with a thin film of Slick Honey then reinstall into the bottom of the Damper-Side upper tube. Seat the Sealhead fully into the upper tube, then reinstall the Hoopster style retaining ring (make sure to install the retaining ring from the end of the Damper Shaft assembly to prevent scratching the shaft. Verify the retaining ring is fully seated by pully on the Damper Shaft Assembly.
With the fork upright, pour the appropriate amount of FOX 5wt. Teflon Infused oil into the Damper-Side upper tube.
|Chassis Type||Damper Oil Volume|
Coat the Topcap Assembly u-cup seal with a thin film of Slick Honey then reinstall the Topcap Assembly into the Damper-Side upper tube. Tighten clockwise to 220 in-lb (24.8 Nm) torque with a 26mm 6-point chamfer-less socket.
Use the Compression Lever as a wrench to turn the Compression Needle fully clockwise until it comes to a gentle stop. Remove the Compression Lever, then reinstall it as close to the back of the crown as possible (in the fully locked out position). Hold the Compression Lever from turning while you reinstall the screw, tightening clockwise to 11 in-lb (1.2 Nm) torque with a 2mm hex wrench.
Replace the Dust Wipers and Foam Rings using steps 7-11 of the standard Dust Wiper and Foam Ring replacement procedures as shown here »
Install the Lower Leg Assembly onto the upper tubes. Inject 10cc of FOX 20wt. Gold oil into each leg through the bottom hole.
Push the Lower Leg Assembly fully onto the Upper Tubes until the Base Studs of the Damper and Air Shaft protrude through the bottom holes in the lowers. Clean any oil off of the shaft threads with Isopropyl alcohol and a lint-free paper towel. Reinstall the Bottom Nuts tightening clockwise to 50 in-lb (5.7 Nm) with a 12mm socket. BOMBER Z2 forks do not use Crushwashers at the Bottom Nuts.
Reinstall the black Rebound Knob, making sure to align the set screw with the flat spot on the Rebound Needle. Tighten the set screw clockwise to 5 in-lb (0.6 Nm) torque with a 2mm hex wrench.
NOTE: Cycle the fork through its travel multiple times to purge any air out of the damper before testing all fork functions.