2013-2015 FIT CTD Cartridge Rebuild
- 803-00-807 Seal Kit: 32mm/34mm FIT CTD, FIT CTD w/Trail Adjust, and FIT Remote
- 398-00-320 Tool: 8mm Shaft Bullet, 32 FIT Cartridge
- 398-00-321 Tool: Bladder Install Spoon, 32 FIT Cartridge
- 398-00-348 Tooling: Bottom-Side Piston Removal Tool, 2013 CTD And CTD-Adj (Inner)
- 398-00-430 Tooling: 34/36/40 Damper Removal Tool
- 398-00-504 Tooling: 2013 CTD Top-Side Piston Removal Tool (Outer)
- 398-00-681 2002-017 32 Damper-side and ALL 32-34-36-40 Spring-side Removal Tool
- 803-00-147 Kit: Shaft Clamps, FORX, Set #2
- 803-00-276 Service Kit: 2010 RL-RLC Hand Bleeder (FOX FIT Bleeder Tool)
- 803-00-809 Kit: Fill Adapter, 32 and 34 FIT CTD Cartridge
- 1/2" Crows Foot
- 1/2" Wrench
- 1/4" Square-drive Ratchet
- 10mm Crows Foot
- 10mm Socket
- 10mm Wrench
- 13mm Cone Wrench
- 15mm Socket
- 2.5mm Hex Wrench
- 2mm Hex Wrench
- 3/8" Square-drive Ratchet
- 6-point Chamfer-less 26mm Socket
- 6-point Chamfer-less 28mm Socket
- 8mm Socket
- Long 5mm Hex Wrench or 1/4" Drive 5mm Hex Bit and Extension
- Seal Pick
- Thin 13mm Crows Foot
- Torque Wrench
- Waste Oil Basin
Note: While there are some minor differences between certain parts in 2013 and 2014 FIT CTD cartridges, the service procedure will be the same for both. Images shown are of a 2013 FIT CTD-Adj cartridge, some 2014 parts (especially the blue CTD lever, set screw, tollerance spring, etc) may appear slightly different but will be installed and removed using the same method as those from a 2013 model.
WARNING: FOX products should be serviced by a qualified 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.
CAUTION: Wear safety glasses during this entire service procedure.
Turn the rebound adjuster all the way counter-clockwise, then remove the red rebound knob with a 2mm hex wrench. Free the cartridge from the lower assembly with a 10 mm wrench (for the 32 mm fork) or a 15 mm wrench (for the 34 mm fork) and the Fox damper removal tool (32 mm PN 398-00-601; 34 mm PN 398-00-430).
Hold the blue CTD lever in place while you remove its set screw with a 2.5mm hex wrench. Replace its blue u-cup seal with the smaller of the two seals in the replacement seal kit.
Use a 6-point 26 mm chamfer-less socket to remove the cartridge from the fork (use a 6-point 28 mm chamfer-less socket for 2013 34 mm forks).
Clamp the cartridge body lightly using the #2 clamps (PN 803-00-147). Carefully release the preload on the CTD compression selection lever detent spring with a pick tool, capturing it and its detent ball with a magnet.
Fully extend the cartridge to minimize internal pressure. Remove the bleed screw with a 2.5 mm hex wrench. Remove the Climb mode blowoff spring and piston underneath.
Remove the cartridge from the clamps and invert over a drain. Cycle the cartridge to completely drain the cartridge oil.
Clamp the cartridge body in the #2 clamps and remove the rebound assembly from the cartridge body with a 13 mm cone wrench.
Clean the shaft clamps and shaft with isopropyl alcohol. Clamp the damper shaft assembly just tightly enough to let you unthread the rebound adjuster from the shaft. Remove the rebound adjuster with a 1/2" wrench (10 mm for the 34), followed by the original seal head.
Note: Be careful to keep all the parts in their original assembly order.
CAUTION: Compression check spring preload may dislodge some parts of the piston assembly during removal of the piston bolt.
Invert the damper shaft assembly in the clamps. Remove the main piston assembly with a six-point 8mm box-end wrench or socket and set all parts aside in order.
Use the rebound tube to carefully dislodge and remove the rebound needle and spring from inside the shaft. Push the rebound needle out through the rebound adjuster end of the damper shaft.
Thoroughly clean all parts and remove and discard the rebound needle o-ring if present. FIT CTD forks no longer utilize an o-ring on the rebound needle.
Clamp the shaft carefully so the rebound adjuster end (the end with no retaining ring) is facing up. Install the 8mm Shaft Bullet Tool (398-00-320) and grease with a thin film of Slick Honey.
Install the new Seal Head Assembly from the rebiuld kit with as shown, then remove the bullet tool.
Reinstall the Rebound Adjuster Assembly as shown and torque to 55 in-lb (6.2 Nm) with a 1/2in. crows foot (10mm for 34mm forks).
Invert the damper shaft and clamp so the end with the retaining ring is facing up. Slowly fill the damper shaft with 10wt. Red until full. Slowly insert the rebound tube into the full damper shaft. This will displace oil.
Install the rebound needle and spring as shown followed by the check limiter/spring perch, spring, main piston assembly and piston bolt. Start threading the piston bolt to keep the parts together but do not tighten.
Make sure that the check shim (the shim under the piston assembly) can move freely as isn't pinched between the piston and the end of the damper shaft. Once sure that the check shim is not pinched, torque the piston bolt to 55 in-lb (6.2 Nm).
Remove the retaining ring and bladder retainer to free the bladder ring, being careful not to scratch the cartridge body.
Be sure NOT to clamp the smooth portion of the body. Always clamp below this section to prevent damage to the bladder sealing surface.
Internally support the coupler with a 5 mm hex inserted through the body from the bottom. Remove the topcap from the bladder and cartridge body assembly with a 6-point chamfer-less 26 mm socket (28 mm socket for 2013 34 mm forks).
Note: At this point the cartridge can disassemble in two different ways. Pay close attention to the instructions for your specific scenario.
Scenario A: Piston Inside Topcap
If your compression piston remains inside the topcap, use the inner Fox piston removal tool (398-00-348) and a 6-point chamfer-less 26mm (28mm for 2013 34mm forks) to remove the piston from the topcap.
Scenario B: Piston Attached to Coupler
If your compression piston remains attached to the coupler, use the outer Fox piston removal tool (398-00-504), a 1/4" drive ratchet, and a ratchet extension with a 5 mm hex internally inserted through the body from the bottom, to remove the piston from the coupler.
Inspect the compression shim stack and set aside in order. Replace any damaged parts as necessary.
Using a blunt tool iniserted through the bleed port, press the flow divider out through the bottom of the topcap. Use your forefinger for support, keeping it square with the topcap as you push it out.
Replace the o-ring on the compression adjuster rod. Make sure the flow plate remains flush with the flow divider as you set this assembly aside for now.
The only two points of potential oil leakage through the topcap are shown below. Be sure to replace both of these o-rings!
Install the flow divider assembly squarely into the topcap, making sure to align and insert the dowel pin into the hole indicated below.
The flow divider is completely installed and squarely seated only when you are able to see an even smooth band of unthreaded wall between the flow divider and topcap threading, as indicated below.
To replace the bladder, first separate the bladder from the threaded coupler at the top of the cartridge body and slide the bladder and ring assembly off the cartridge body, as shown.
Grease the inside and outside of the bladder at both ends and install the bladder ring as shown.
Clamp the cartridge body so the coupler is facing up. Reinstall the shim stack in its original configuration.
Installing the compression piston backwards will require a new topcap assembly in addition to various other small cartridge parts. Make sure you install the compression piston as shown (with the bevel facing up toward the topcap).
Be sure to place the compression piston in its correct orientation (the beveled end oriented towards the topcap). Apply a liberal coating of slick honey on the outside of the bladder before installing the topcap assembly.
As you thread the topcap onto the compression piston, apply gentle upward pressure on the bladder and bladder ring. This pressure helps to force the bladder up into the topcap as you are threading it down. If necesarry, the bladder installation tool (PN: 398-00-321) can be used to help tuck the bladder into the topcap. Allow the bottom end of the bladder to rotate around the cartridge body as you thread to prevent the bladder from twisting.
When the topcap is threaded on, make sure the bladder is seated evenly into the topcap assembly with no distortions.
Tighten the topcap onto the bladder and cartridge body assembly to 75 in-lb (8.5 Nm) torque.
Place the bladder and cartridge body assembly into the second largest hole in the #2 clamps as shown; loosely resting the bladder ring on the clamps, no clamping pressure applied to the bladder ring. While gently tugging the topcap from below, you will seat the bladder in the bladder ring deep enough to install the bladder retainer and retaining ring.
Install the damper shaft assembly into the cartridge body assembly. With a 13 mm crows foot, tighten the seal head into the cartridge body to 75 in-lb (8.5 Nm) torque.
Hand Bleeding the Cartridge
This section can be skipped by those that have access to a vacuum/fill machine (Andreani).
With the cartridge fully compressed, thread the bleed adapter tool (PN 803-00-809) into the bleed hole in the topcap. Place the rubber tip of the Fox FIT bleeder tool (PN 803-00-276) into the adapter. Fill the bleeder tool with Fox red oil until full.
Repeatedly squeeze and release the bladder to force out any air. Next, cycle the shaft slowly down to full extension, drawing oil into the cartridge. If bubbles are present in the syringe oil, wait until the bubbles have risen to the top before drawing clear oil down into the cartridge.
Repeat the squeeze, cycle, and wait process described above, until air bubbles stop appearing in the syringe as you squeeze and cycle the cartridge.
Do not let the oil level in your syringe drop to the point where you can ingest air into the cartridge. Add oil to the syring as necesarry.
The bleed process is complete when air bubbles are no longer produced as you squeeze the bladder and cycle the cartridge. Once complete, remove the bleed adapter tool and top off the bleed hole with 10wt. red oil.
Insert the blowoff piston and spring into the bleed hole. Fill the recess in the underside of the bleed screw with a small amount of Slick Honey and install it using the 2.5 mm hex driver. This completes the hand bleeding section. At this point, you should cycle the damper and verify that there is no sound of trapped air inside the cartridge. Repeat the bleed process if necessary to remove any trapped air from the cartridge.
Final Topcap Reassembly
Thread the set screw for the blue CTD lever a few turns into the compression adjustor rod. This enables you to pull the rod upwards for optimal installation of the detent ball with spring that follows.
The bleed adapter tool (or a small socket) is handy for holding the compression rod detent ball in place as you install its spring.
Compress the detent spring with a pick tool or flat driver while pushing the compressed spring down into the slot with a blunt tool.
Install the detent spring retainer plate followed by the tolerance spring onto the compression adjuster rod.
Install the cartridge into the fork, tightening to 220 in-lb torque with a 6-point 26 mm chamfer-less torque socket for 32mm forks (28mm for 2013 34mm forks).
Use the compression selector lever to find the middle detent setting (trail mode). Remove the compression lever and reinstall it, with the lever pointing to the three o'clock position from the rider's perspective. Hold the lever as shown when tightening the set screw with a 2.5 mm hex driver to 11 in-lb (1.2 Nm) torque.
Invert the fork and fill with the appropriate amount of 20wt. Gold oil. FOX 20wt. Gold is compatible with all Low-Friction 34mm dust wipers. FOX 20wt. Gold oil should only be used with compatible 32mm dust wipers found in kit: 803-00-878.
|Damper Side Bath Oil|
|Spring Side Bath Oil|
|All FLOAT &
Additional information regarding updating from 10wt. Green oil to the new 20wt. Gold oil can be found at: http://www.ridefox.com/help.php?m=bike&id=452 »
Install the bottom nut with a new crush washer, tightening to 50 in-lb torque. Install the rebound knob with a 2 mm hex, making sure the set screw correctly settles into its indentation on the rebound adjuster; tighten to 11 in-lb torque.
After cleaning the exterior of your fork, test the function of the FIT CTD cartridge before considering this service complete.