Rebuilding your Fox DPX2 Factory rear shock at home can significantly improve the performance and lifespan of your suspension system. This guide provides detailed, step-by-step instructions to help you perform a full rebuild. Whether you’re a seasoned mechanic or a rider looking to save on maintenance costs, this article will equip you with the knowledge to handle the process yourself.
Tools Required
- 3/8″ Ratchet Wrench
- Torque Wrench [paid link]
- Snap Ring Pliers
- 8mm and 10mm Allen Wrenches [paid link]
- Suspension Fluid (Fox 20wt or recommended alternative)
- Fox Rear Shock Oil (for the DPX2)
- Small Flathead Screwdriver
- Isopropyl Alcohol (for cleaning)
- Shock Pump
- 3mm, 4mm, and 5mm Allen Wrenches [paid link]
- Soft Cloths
- Plastic or Aluminum Prying Tools
- Compressed Air (optional)
- Service Kit for Fox DPX2 (Includes seals, o-rings, and other replacement parts)
Disassembly of the DPX2 Factory Rear Shock
Before you begin, make sure you have a clean, well-lit work area. You’ll also want to gather all of your tools and the necessary suspension fluids to avoid interruption during the rebuild.
1. Remove the Rear Shock from the Frame
To begin disassembling your DPX2 Factory rear shock, you first need to remove the shock from the bike frame. Use an 8mm Allen wrench [paid link] to unscrew the mounting bolts securing the shock. Carefully remove it from the frame, ensuring you keep track of any washers or spacers for reassembly.
2. Clean the Shock Exterior
Once the shock is removed, use a soft cloth and some isopropyl alcohol to clean off any dirt, dust, or debris. Cleaning the shock is critical to prevent contaminants from getting into the internal components during disassembly.
3. Remove the Air Canister
Using a 10mm Allen wrench [paid link], loosen the two bolts securing the air canister. The DPX2 Factory rear shock features an air spring that is separated from the damper unit by a removable air can. Remove the canister carefully, ensuring you don’t damage any seals during the process.
4. Extract the Internal Components
After removing the air canister, use the snap ring pliers to remove the snap rings that hold the internal components in place. This step will allow you to access the shock’s damper system and other internal parts. Be cautious, as the internal components are delicate and may be under some pressure.
5. Disassemble the Damper
Next, carefully disassemble the damper system. This step requires a few different-sized Allen wrenches (usually 3mm, 4mm, and 5mm) to remove the damper bolts and components. Take note of the order and orientation of each part as you remove them for easy reassembly.
Replacing Seals and O-Rings
One of the most critical steps in the rebuild is replacing the seals and o-rings. Over time, these parts wear down, leading to reduced performance or leakage.
1. Replace the Air Shaft Seal
Remove the air shaft seal from the shock. This part is essential to keeping the air spring sealed and functioning. Clean the surface and install a new seal from your Fox DPX2 service kit. Make sure the new seal is properly aligned and seated to prevent air leaks.
2. Replace the Damper Seals
The damper system includes multiple seals that ensure smooth operation. Replace all seals in the damper unit to ensure the shock operates at its full potential. Use a small flathead screwdriver to carefully remove the old seals, being careful not to scratch or damage the internal components.
3. Lubricate the New Seals
Before installing the new seals, lightly lubricate them with suspension fluid to reduce friction and ensure a smooth fit. Be sure not to over-lubricate, as excess fluid can cause performance issues.
Cleaning and Inspection of Internal Components
Before reassembling the shock, inspect all internal components for wear and damage. Clean all parts thoroughly, using isopropyl alcohol to remove any old suspension fluid or debris. Take the time to examine the damper unit, air shaft, and other internal parts for signs of wear such as scratches or excessive fluid buildup.
1. Check for Scratches or Wear on the Shaft
Inspect the shock shaft for any visible scratches or abrasions. Small imperfections can damage the seals, leading to poor performance or even failure. If any damage is found, consider replacing the shaft or taking the shock to a professional for further assessment.
2. Examine the Damper Cartridge
Check the damper cartridge for any issues. If the damping feels inconsistent or you notice fluid leaks, the cartridge may need replacement. While Fox components are generally durable, it’s important to address any issues promptly to prevent damage to the shock.
Reassembling the DPX2 Factory Rear Shock
Once you’ve replaced the seals and inspected all components, you can begin reassembling the shock.
1. Install the Damper and Internal Components
Start by reassembling the damper and internal components. Carefully insert the damper back into the shock body, ensuring everything is in the correct order. Tighten the bolts to the manufacturer’s recommended torque specifications to avoid damaging the shock during reassembly.
2. Reinstall the Air Canister
Place the air canister back onto the shock body. Make sure the air canister seals are intact and properly seated to prevent air leaks. Tighten the mounting bolts with a torque wrench [paid link], ensuring they are securely fastened.
3. Reinstall the Shock on the Bike Frame
After reassembling the shock, reattach it to the bike frame. Tighten the mounting bolts securely with an 8mm Allen wrench. Be sure to torque the bolts according to Fox’s specifications to avoid any potential damage or safety issues.
Setting the Air Pressure and Fine-Tuning the Shock
Once the shock is reassembled and mounted back on your bike, you’ll need to set the proper air pressure for your weight and riding style. Use a shock pump to inflate the air chamber to the recommended pressure based on your body weight. You may need to make adjustments after a test ride to fine-tune the shock’s performance.
1. Set the Air Pressure
Refer to the Fox DPX2 manual for the recommended starting air pressure based on your body weight. After setting the air pressure, check for any signs of leakage around the air canister and seals.
2. Fine-Tune the Rebound and Compression Damping
Use the adjustment dials on the DPX2 to fine-tune the rebound and compression damping settings. Start with the manufacturer’s baseline settings and make adjustments based on your personal preferences and riding conditions.
Troubleshooting Common Issues
Despite following all the steps carefully, there may still be a few issues to troubleshoot. Here are some common problems and how to address them:
1. Air Leaks
If you notice air leaking from the shock, recheck the air canister seals and the air shaft seal. If the seals appear worn or improperly installed, replace them. Air leaks are often caused by damaged or incorrectly installed seals.
2. Inconsistent Rebound or Compression
If the rebound or compression feels inconsistent, check the damper unit for contamination or damage. Ensure that all seals are replaced and that no fluid has leaked from the damper unit.
3. Loss of Air Pressure
Loss of air pressure over time can be caused by damaged seals or worn parts. If you notice that the shock isn’t holding air pressure, inspect the internal components for damage and replace any worn seals.
Conclusion
Rebuilding your Fox DPX2 Factory rear shock at home is a satisfying and rewarding task for any cyclist. By following the steps outlined in this guide, you can ensure that your shock remains in top condition, providing smooth, consistent performance on the trails. Regular maintenance and proper care will help prolong the lifespan of your rear shock and maintain optimal performance for years to come.