SERVICE PROCEDURES
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 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 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.
Reassembly
Step 1
Make sure the white backup ring is still installed in the end of the shaft. Install a new 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.
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 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.