2016-2018 36mm F-S/P-Se FIT4 3pos w/Adj Damper Cartridge Rebuild
- 398-00-371 Tooling: Sealhead To Shaft Bullet, 10mm
- 398-00-682 2005-017 34-36-40 Damper-side Removal Tool
- 398-00-702 Tooling: Fork Topcap Socket, 26mm, 3/8 Drive
- 803-00-147 Kit: Shaft Clamps, 07 FORX, Set #2 (32 X Body, 36, 40 Forx)
- 803-00-276 Service Kit: Hand Bleed, Syringe and Tube, 2010 32 Fit RL-RLC Cartridge
- 803-00-830 Service Set: Tooling: 2014 RC2, Shaft Clamps
The following procedure guides you through the rebuild of the 36mm F-S/P-Se FIT4 3pos w/Adj damper cartridge.
Complete part information and technical drawings for 2016 36mm forks can be found by clicking: 36mm Part Information »
To link directly to the technical drawings for the 2016 36mm FIT4 3pos w/Adj cartridge and its assemblies, click here »
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: 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.
Removal From Fork Chassis
For Levers: Set the fork to Open mode by turning the blue lever fully counter-clockwise. Hold the black knob while unthreading the set screw (counter-clockwise) with your 2.5mm hex wrench.
For Remote: Cut off the end crimp, unthread the cable pinch bolt without removing it completely, then remove the cable and housing. Hold the black knob while unthreading the set screw (counter-clockwise) with your 2.5mm hex wrench.
For Levers: Remove the 2.5mm hex screw followed by the black open mode adjust knob and the blue lever.
For Remote: Remove the 2.5mm hex screw, then lift up on the blue pulley to remove it, the black open mode adjust knob, and the torsion spring. Remove the black remote housing.
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 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 Tool 398-00-682 to dislodge the shaft 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.
With a chamfer-less 6-point 26mm socket (PN: 398-00-602), unthread the damper cartridge completely (counter-clockwise). Pull straight up to remove the entire damper cartridge from the right side upper tube. Clean off excess bath oil with a lint-free paper towel.
Damper Cartridge Rebuild
Clean the cartridge body with isopropyl alcohol and a lint-free paper towel, then clamp it in your shaft clamps (PN: 803-00-830).
Break the sealhead (listed as the bearing housing assembly on the technical drawings) free from the cartridge body 1/4 turn with a 19mm wrench (counter-clockwise when viewed from below). Remove the cartridge from the vice before unthreading the sealhead from the cartridge body over an oil drain.
Squeeze the bladder while holding the open cartridge body end over your oil drain to evacuate most of the oil from the damper before moving to the next steps.
Remove the retaining ring and bladder ring retainer being careful not to scratch the smooth bladder sealing surface on the black cartridge body.
Slide the lower bladder ring up toward the fatter end of the bladder to release it from squeezing the bladder against the cartridge body.
Slide the upper bladder ring down away from the topcap to release the bladder. Slide the bladder with bladder rings off of the open cartridge body.
Remove both bladder rings and set them aside. Discard the original bladder as you will be installing a new one from the kit in a later step.
Clamp the cartridge body in your shaft clamps, making sure not to clamp the smooth bladder sealing surface. Remove the small round wire retaining ring that retains the compression adjust coupler. For best results, use a sharp pick following the detent cutout nearest the middle of the ring, rather than starting from one of the rings ends. The last two images for this step illustrate the technique with the ring already removed as an example.
Using the set screw that retains the levers, pull up on the compression adjust coupler slowly while covering the spring loaded detent ball. Be careful not to let the detent ball eject as the compression adjust coupler is pulled up. Set these parts aside.
Use a 19mm wrench to hold the compression clamp stationary while you unthread the topcap body counter-clockwise. Lift the cartridge body to remove.
Lift out the compression adjust needle and lockout selector with wave spring and set aside. Lift out the butterfly valve followed by the compression pistion and valving assembly.
Remove the o-ring inside the compression clamp and replace it with a new greased one from the kit.
Unthread (counter-clockwise) the compression clamp from the cartridge body. Remove and replace the o-ring inside the bottom of the compression clamp, making sure to retain the check valve, spring, and valve in their original order as shown.
Reinstall the compression adjust needle and lockout selector with wave spring into the underside of the topcap. Make sure the lobes of the lockout selector allign with the hole in the bottom of the compression selector shaft.
Turn the compression selector shaft to the middle position, then install the butterfly valve onto the lockout selector making sure that the holes in the butterfly valve allign with the appropriate sized posts on the lockout selector.
Locate the feature that protrudes from the circumference of the compression piston and allign that with the notch in the topcap body. Install the compression piston into the topcap with it's flat side facing toward the butterfly valve. Press down on the piston after installation to check for spring return. This helps verify correct piston installation. Install the valving assembly onto the compression piston, centering the shims on the stand-offs in the center of the piston.
Install the compression clamp onto the inverted topcap assembly and thread together until hand tight.
Thread the rebuilt topcap assembly onto the cartridge body and tighten to 75 in-lb (8.5 Nm) with your 6-point chamfer-less 26mm socket. This will tighten the topcap to the compression clamp and the compression clamp to the cartridge body in one operation.
Apply a thin coating of Slick Honey to the inside and outside of both ends of a new bladder from the kit, then install the upper bladder ring. The upper bladder ring is not directional.
Install the lower bladder ring as shown with it's larger end oriented toward the small end of the bladder.
Install the new bladder assembly onto the cartridge body as shown. Engage the fat end of the bladder with the sealing surface on the compression clamp.
Seat the upper bladder ring against the compression clamp. You can rest the upper bladder ring on your soft-jawed vice and push down on the topcap to seat the bladder ring.
Place the bladder and cartridge body assembly into the second largest hole in the sahft clamps #2 (PN: 803-00-147) as shown; loosely resting the bladder ring on the clamps, no clamping pressure applied to the bladder ring. While gently tugging the bladder from below, you will seat the bladder in the bladder ring deep enough to install the bladder retainer and retaining ring.
Remove the detent ball and spring from the compression adjust coupler and set them aside. Temporarily install the compression adjust coupler into the compression selector shaft to seal the topcap. Make sure to engage the internal hex to seat the compression adjust coupler fully.
Rest the topcap in your 6-point chamfer-less 26mm socket and fill the cartridge body with FOX R3 5wt oil leaving approximately 2 inches (50mm) of air space above the oil within the cartridge body. Squeeze the bladder to expell air and ingest oil. Repeatedly squeeze the bladder and add oil until the oil level is approximately 2 inches (50mm) below the end of the body when not squeezing the bladder.
Slide the sealhead toward the rebound adjuster (listed as the base stud in the technical drawings), leaving about 1 inch (25mm) space between the sealhead and rebound adjuster. Clean the shaft with isopropyl alcohol and a lint-free paper towel.
Clamp the shaft in your shaft clamps (PN: 803-00-830) and remove and discard the o-ring from the rebound adjuster.
Carefully apply heat to the shaft at the rebound adjuster with a propane torch for 5-10 seconds to break down the Loctite. Unthread the rebound adjuster counter-clockwise with a 9mm wrench.
Lift the rebound adjuster with rebound needle straight up and out of the shaft. Replace the o-ring at the fluted end of the needle with a new greased one from the kit.
Slowly unthread the rebound adjuster (counter-clockwise) from the rebound needle. After a few turns you will be able to see the rebound detent ball. Hold the needle with the rebound detent ball pointing up as you slowly unthread the rebound adjuster fully.
Coat the threads of the rebound needle with waterproof grease such as Sta-Lube SL3125. While holding the rebound needle with the detent ball facing up, thread the rebound adjuster clockwise onto the needle. Thread the adjuster fully onto the needle, then back it off 1/4 turn.
Remove and discard the original sealhead. Install the 10mm bullet tool (PN: 398-00-371) into the shaft, then coat the bullet with a film of Slick Honey.
Install the new sealhead from the kit onto the shaft with its threaded end first. Remove the bullet tool.
Drop the rebound needle and adjuster assembly into the shaft, then apply a drop of Loctite 262 to the rebound adjuster threads. Tighten the rebound adjuster to the shaft to 30 in-lb (3.4 Nm) torque with a 9mm crows foot.
Temporarily reinstall the rebound knob with your 2mm hex wrench making sure to allign the set screw with the detent in the rebound needle. Turn the rebound adjuster counter-clockwise to its full open position. Remove the rebound knob.
Remove and replace the pink piston glide ring with a new one from the kit. The new glide ring will appear larger than the old one, but will compress once inside the cartridge body. Slide the sealhead all the way toward the rebound piston end.
Top off the cartridge body with FOX R3 5wt. oil then install the shaft assembly threading the sealhead onto the cartridge body until hand tight.
Clean the cartridge body with isopropyl alcohol and a lint-free paper towel, then clamp it in your shaft clamps (PN: 803-00-830). Tighten (clockwise when viewed from below) the sealhead to the cartridge body to 55 in-lb (6.2 Nm) torque with a 19mm crows foot.
Remove the compression adjust coupler by pulling it up. Install a piece of clear vinyl tubing with an internal diameter of 5/16 inches (~8mm) onto the compression selector shaft. Install a FOX bleeder syringe (with plunger removed) into the vinyl tubing. Make sure that the tubing fits tightly and makes a complete seal. Turn the compression selector shaft to its fully counter-clockwise setting to set the damper in open mode for easiest bleeding.
Slowly cycle the shaft up while squeezing the bladder to force any trapped air out into your syringe. Do not release your squeeze on the bladder or cycle the shaft down until all air bubbles in your syringe have risen to the surface. Do not suck bubbles back into the cartridge. Periodically add oil to your syringe so you do not let the syringe go dry as the cartridge ingests oil. Repeat this step until all air trapped in the cartridge is bled out.
With the cartridge fully extended, remove the bleed syringe and vinyl tubing and top off the compression selector shaft with FOX R3 5wt. oil. Remove and replace the o-ring on the compression adjust coupler with a new greased one from the kit. Reinstall the detent spring and ball. Use Slick Honey to help retain the detent ball and spring.
Install the compression adjust coupler with detent ball and spring into the compression selector shaft. Push the detent ball inward while installing the compression adjust coupler. You may need to rotate the coupler slightly to engage the internal hex feature. Push it all the way down to seat it properly.
Remove the set screw and install the round wire retaining ring. Reinstall the set screw and pull up to verify that the retaining ring is fully seated. Remove the set screw one last time.
Cycle the damper by hand to check that all air was properly bled out of the cartridge in previous steps. If you hear or feel excessive air still trapped within the cartridge, go back to step 38 and try bleeding the cartridge again.
Reinstallation Into Fork Chassis
Install the cartridge into the upper tube. Tighten the topcap clockwise to 220 in-lb (24.8 Nm) torque with your 6-point chamfer-less 26mm socket.
Install a new crush washer into the damper side bottom nut (use a small amount of Slick Honey to retain the crush washer during installation). Install the bottom nut, tightening to 80 in-lb (9.0 Nm) with a 15mm socket. 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. Replace the black rebound knob cover if present.
For Levers: Use the blue lockout knob to set the cartridge to its middle position. Remove the knob and reposition it to point to the rider's three o'clock position. Install the black open mode adjust knob followed by the set screw. Hold both knobs stationary while tightening the set screw to 11 in-lb (1.2 Nm) with your 2.5mm hex wrench. This completes reinstallation for lever equipped forks.
For Remote: Skip to step 5.
For Remote: Place the black remote housing into the topcap with the cable stop oriented toward the rider's 1 o'clock position.
Coat the torsion spring and the blue remote pulley glide ring with a thick film of waterproof grease such as Sta-Lube SL3125 then install one tang of the spring into the hole in the underside of the blue remote pulley.
Insert the remote pulley and greased torsion spring into the black remote housing so the pinch bolt is at the rider's 1 o'clock position. Make sure that the bottom spring tang seats into a hole in the black remote housing.
Install the black Open mode adjust knob. Start the 2.5mm hex screw only 1-2 turns. Do not tighten it fully in this step.
Lift up on the black remote housing and rotate counter-clockwise until the cable stop is oriented toward the riders 7 o'clock position (180 degrees). Lower the black remote housing back onto the topcap wrench flats. If you cannot lift the black remote housing, try loosening the 2.5mm hex screw until it retains the knobs while allowing you to lift the black housing past the topcap wrench flats to rotate it.
Hold the black Open mode adjust knob from rotating while you tighten the 2.5mm hex screw to 11 in-lb (1.2 Nm). Do not allow the blue pulley to rotate while tightening the 2.5mm hex screw.
Clean the exterior of your fork and test all of its functions before reinstalling onto the bike.