2025 Transfer 300 Hour Full Rebuild (Common shop tools only)
Required Parts
- 025-03-003-A Oil: AM, FOX FLOAT Fluid [16 oz.]
- 025-03-035 Oil: AM, FOX 1.5wt Synthetic Oil [16 oz.], Clear
- 803-04-124 Seal Kit: 2025 Transfer Seatpost, 30.9/31.6, Full Rebuild with Sealhead and Piston Assembly
- 803-04-125 Seal Kit: 2025 Transfer Seatpost, 34.9, Full Rebuild with Sealhead and Piston Assembly
Required Tools
Sections
WARNING: Always wear safety glasses and protective gloves during service to prevent potential injury. Failure to wear protective equipment during service may lead to SERIOUS INJURY OR DEATH.
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.
WARNING: Modification, improper service, or use of aftermarket replacement parts with FOX forks, shocks, and seatposts may cause the product to malfunction, resulting in SERIOUS INJURY OR DEATH. DO NOT modify any part of a fork, shock, or seatpost 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.
WARNING: FOX products contain pressurized nitrogen, air, oil, or all 3. Misuse can cause property damage, SERIOUS INJURY OR DEATH. DO NOT puncture, incinerate or crush any portion of a FOX product. DO NOT attempt to disassemble any portion of a FOX product, unless expressly instructed to do so by the applicable FOX technical documentation, and then ONLY while strictly adhering to all FOX insturctions and warnings in that instance.
IFP Information:
IFP Pressure: 275-325Psi.
TRAVEL/DIAMETER | IFP Height (all measurements +/- .025in) |
120mm-30.9/31.6 | 1.32in |
150mm-30.9/31.6 | 1.51in |
180mm-30.9/31.6 | 1.68in |
210mm-30.9/31.6 | 1.84in |
240mm-31.6 | 2.19in |
120mm-34.9 | 1.26in |
150mm-34.9 | 1.42in |
180mm-34.9 | 1.57in |
210mm-34.9 | 1.72in |
240mm-34.9 | 1.88in |
**This 300 hour full seatpost rebuild can be performed with common workshop tools, however, while not required, FOX has developed specific tooling for this seatpost. Please see the listings below for tool details.**
398-00-740 | Service Tool: Push Rod, Delrin, Transfer |
803-04-042 | Kit: Tooling: 2025 Transfer, IFP Depth Tool Set |
398-00-966 | Tooling: Bullet, Transfer, 7.5mm Shaft |
398-01-137 | Tooling: IFP Spacer, MY25 Transfer, 30.9/31.6 |
398-01-138 | Tooling: IFP Spacer, MY25 Transfer, 34.9 |
398-01-162 | Tooling: 2025, Transfer, Open Valve Thumb Screw |
398-01-163 | Tooling: 2025, Transfer, Wiper Install Tool, 30.9, 31.6 |
398-01-164 | Tooling: 2025, Transfer, Wiper Install Tool, 34.9 |
398-01-165 | Tooling: 2025, Transfer, Vacuum Bleed Fitting |
Disassembly
Step 1
Remove the Saddle Clamps and hardware. Turn the 4mm hex bolts counter-clockwise to remove them from the Saddle Clamp Nuts. Set all clamps and hardware aside.
Step 2
Remove the black air cap at the top of the post by turning it counter-clockwise with a 10mm socket, then slowly release the air pressure by depressing the Schrader valve with a lint-free towel covering the valve to prevent any fluid spray.
Step 3
Push Top Cap down and use a seal pick or other small tool to rotate the retaining ring so that the ring gap is at the front of the post. Pull the retaining ring out with your fingers.
Step 4
Thread your FOX shock pump onto the top cap clockwise then pull up to remove the cap from the upper post.
Step 5
Clean your bike work stand clamps and the exterior of the seatpost to prevent damage during clamping. Clamp the seatpost in your workstand, then unthread the Lower Post Collar by turning it counter-clockwise by hand. If too tight to unthread by hand, you may use channel lock type pliers with a shop rag to protect the collar from damage. Remove the o-ring under the collar.
Step 7
Separate the Upper Post Assembly from the Lower Post. Take note of the position of the ball bearing in the base lug and mark the anti-rotation hole that the ball bearing was found in. This is in case the ball falls out during service.
If you use a Sharpie or other marker to make this mark, take care not to remove the mark as you clean parts throughout the rebuild. A scribed line is also an option for marking the position of the ball bearing.
Remove the keys and index pins.
Step 8
Clamp the Upper Post Assembly in your bike stand. Remove the Pushrod from the bottom of the Shaft. Using a T25 torx to hold the Shaft in place, unthread the Base Lug counter-clockwise from the Shaft using a 10mm wrench.
Step 9
Remove the Lower Bushing followed by the Lower Bushing energizer o-ring, Top Out Washer, and Collar assy.
Step 10
To replace the Dust Wiper use a flat screwdriver with a twisting motion to lift up on the Wiper.
Step 11
Setting the Collar Assembly against a table, use a pick to remove the retaining ring that sits between the Bushing Carrier and Collar.
Step 12
Clamp the Upper Post in your bike stand (you may need to use a soft jaw vice to hold the head of the Upper Post for this procedure). Use a pair of smooth-jawed parallel pliers (Knipex) to unthread the Bottom Seal Head from the Upper Post. Pour out all oil into your waste oil basin. Push the IFP out through the top using a long Delrin Push Rod or a nonmetallic dowel. Note: IFP color may vary.
Step 13
Very GENTLY clamp the wrench flats on the Pressure Tube in a soft jaw vice and unthread Bottom Seal head counter-clockwise from the pressure tube with your Knipex smooth-jawed parallel pliers. Over-clamping the pressure tube will bind the threads, making it very difficult to loosen the seal head.
Step 14
Remove the Main Shaft Assembly then remove Bottom Seal Head from Main Shaft. Pour the oil out from Pressure Tube into your wate oil basin. Remove the bleed screw from the end of the pressure tube assembly by turning it counter-clockwise with a 2mm hex wrench. Set the bleed screw aside.
Step 15
Unthread the Main Piston using your T25 in the bottom of your Main Shaft and a 10mm wrench at the base of the Main Piston. Remove the o-ring and backup ring from the end of the shaft with a plastic pick.
Reassembly
Step 1
Install a new backup ring and greased o-ring from the kit into the end of the shaft as shown. Thread the new Piston Assembly from the kit onto Main Shaft. Use a 10mm wrench to hold the Piston Assembly while you tighten the shaft clockwise to 40in-lb (4.5Nm) with a T25 Torx driver.
Step 2
Coat the shaft threads and the inside of the sealhead with Slick Honey, then install the new Bottom Seal Head from the kit onto the Main Shaft.
Step 4
Thread the Base Lug onto the Main Shaft. Then thread the Actuator Assembly onto the Base Lug. Use a Zip Tie to hold the actuator open.
Step 6
Thread on Bottom Seal Head and torque to 60in-lb (6.8Nm) with a 24mm socket (for 30.9mm/31.6mm posts) or a 26mm socket (for 34.9mm posts). You must push Shaft into Pressure Tube, remove the Base Lug and Actuator in order to get the socket onto the Bottom Seal Head.
Step 7
Install Upper Bushing Carrier Assembly from kit into your Post Collar. Hold Collar against a flat surface and reinstall your reatining ring.
Step 8
Install new wiper seal/anti-rattle ring assembly from the kit. Bend old Lower Bushing so it fits around Wiper and use a soft jaw vise to press Wiper Seal into Collar Assembly. The top of the wiper flange must sit flush with the top of the collar.
Step 9
Pack the new wiper with Slick Honey, then reinstall Collar Assembly onto Upper Post, followed by Top Out Washer
Step 10
Install new greased Lower Bushing Energizer O-Ring and new Lower Bushing from kit. Orient Bushing split to side of the post.
Step 11
Reinstall Pressure Tube Assembly into Upper Post and torque to 90in-lb(10.2Nm) with a 24mm socket (for 30.9mm/31.6mm posts) or a 26mm socket (for 34.9mm posts). You can do this on your bike stand or soft jaw vice. Once torqued reinstall your Base Lug and Actuator.
Step 12
Invert Upper Post so that it is upright. Fill with Fox 1.5wt. Clear oil to about an inch of the top of the post. Move the post slowly and cover the top with a rag to reduce oil loss. Listen for bubbles and keep adding oil as neccessary while cycling the Shaft until no more bubbles are seen.
Step 13
When no new bubbles appear while cycling the Shaft, fully extend the Shaft. Coat the 2mm hex wrench and bleed screw with Slick Honey, then reinstall the bleed screw tightening to 3in-lbs (0.94Nm). Top off the oil level.
Step 14
Remove the IFP screw with a 5mm non-ball end hex wrench by unthreading it counter-clockwise. Replace the IFP seals with new greased ones from the kit making sure they are not twisted after installation. Reinstall IFP into Upper Post with screw out. Note IFP color may vary.
WARNING: DO NOT use a ball-end hex wrench to install the IFP screw as it may allow for cross-threading. Only use a straight-ended hex wrench to install the IFP screw. Failure to use the proper tools may cause permanent damage to the seatpost.
Step 15
Set your calipers to the correct IFP height for your post as shown in the chart below. Find a socket that is the correct diameter to fit into the top of the post and contact the tabs at the top of the IFP. Mark the socket at the IFP height. Use the socket to push your IFP into the post until the mark on the socket is aligned with the highest part of the upper seatpost. Use a plastic pick to hold the IFP from turning while you tighten the IFP screw to 3in-lb (0.34 Nm) torque with a 5mm non-ball end hex wrench. Verify correct IFP depth by measuring to the top of the IFP tabs with your calipers.
TRAVEL/DIAMETER | IFP Height (all measurements +/- .025in) |
120mm-30.9/31.6 | 1.32in |
150mm-30.9/31.6 | 1.51in |
180mm-30.9/31.6 | 1.68in |
210mm-30.9/31.6 | 1.84in |
240mm-31.6 | 2.19in |
120mm-34.9 | 1.26in |
150mm-34.9 | 1.42in |
180mm-34.9 | 1.57in |
210mm-34.9 | 1.72in |
240mm-34.9 | 1.88in |
Step 16
Pour out the excess oil from the IFP chamber, then inject 1.5cc of FLOAT FLUID into the IFP chamber.
Step 18
Reinstall Top Cap into Upper Post. Install retaining ring(orient ring gap to relief at front of post) and charge post up to 325psi. Reinstall Air Valve Cap finger tight using a 10mm socket.
Step 19
Remove Actuator and pull Pushrod out of the bottom of the shaft. Hold the Base Lug in place with your 10mm wrench while you tighten the shaft COUNTER-CLOCKWISE into the Base Lug, tightening (counter-clockwise) to 30in-lb (3.4Nm) torque. Reinstall the Push rod after torque.
Step 20
Coat the entire upper post below the collar and the top 2.5" of the inside of the lower post with a thick (clump-level) film of Slick Honey. Install the Index Pins and Travel Adjust Keys.
Step 21
Rotate the base lug so that the ball aligns with the back index pin.
Align the ball bearing with the groove in the inside of the Lower Post that is closest to the laser etching on the back of the Lower Post. Align the back of the upper post (higher of the two saddle mounting tabs) with the laser-etching on the back of the lower post. Slowly feed the Upper Post Assembly into the Lower Post.
Note: Increased force may be required to install the upper post into the lower post as the lower bushing is energized by the o-ring.
Step 22
Thread the Actuator into the end of the Lower Post. Tighten the Bottom Cap clockwise using its thickest part to 40 in-lb (4.5 Nm) torque.
Step 23
Install the Lower Post Collar, tightening clockwise until hand tight. Reinstall the Lower Post Collar O-ring.
Step 24
Reinstall the Saddle Clamps making sure all arrows face the front of the post. Clean the exterior of your post with Isopropyl alcohol.