FOX DHX 3.0 / 4.0 / 5.0 Full DIY Rebuild Tool Kit

A full-service rebuild kit for classic FOX DHX shocks (3.0, 4.0, 5.0). These shocks were extremely popular throughout the 2010s, but official manuals are no longer available. This kit includes all the tools you need for a complete service of the dynamic seals, IFP, and more.

Bomber CR on the pictures. Shares the same piggy back and damper tube diameters as the Fox DHX models.

Do not forget to get yourself a schrader valve core tool! 

• Essential Tools (You might need to replace the core if leaking)

Get this seal kit from MTB Hydraulics for the rebuild.

 What’s Included (and Optional)

• DHX Shaft Clamp (1/2" + 5/8") : works for both shaft sizes on DHX 3/4/5, RC2, and RC4
• Damper Body + Reservoir Clamp : optional, only needed if leaking from the body or piggyback
• IFP Depth Tool (Graduated) : for precise IFP reset

 Important Notes

•  Most users only need to replace dynamic seals, main shaft seal, wiper, and IFP seal
•  The boost valve exists on some DHX 5.0 shocks, leave it fully open during bleeding
•  Do not open the damper body or piggyback unless it’s actively leaking, Loctited shut and may ruin decals
•  Rebound issues are often due to pressure loss or degraded oil, not mechanical damage
• IFP pressure: Fill to at least 125 psi (recommended range: 125–150 psi)

 IFP Depth Chart

Metric Shocks:

• 190mm x 50mm = 32mm
• 200mm x 50mm = 32mm
• 200mm x 57mm = 33mm
• 215mm x 64mm = 34mm
• 222mm x 64mm = 34mm
• 241mm x 76mm = 38mm

Imperial Shocks:

• 7.500" x 2.00" = 1.25"
• 7.875" x 2.00" = 1.25"
• 7.875" x 2.25" = 1.30"
• 8.500" x 2.50" = 1.35"
• 8.750" x 2.50" = 1.35"
• 9.500" x 3.00" = 1.48"

 How to Bleed and Rebuild

• Watch this MTBHydraulics video
• DHX Service PDF Manual

1. Fully open the boost valve (some models unscrew out) but yeah, just try it before to see which direction makes the compression. Don't forget to open both highspeed and low speed adjusters.
2. Use the rubber glove technique, no syringe needed
3. Partially insert IFP into filled piggyback
4. Fill the damper body completely, then insert the piston slowly
5. Thread in the sealhead and crack the bleed port before final tightening
6. Set exact IFP depth using the IFP Depth Tool

 You Might Also Need

• Luggage Scale Torque Calculator
• Soft Vise Jaws
• Essential Tools Starter Pack