DIY Suspension Fork Oil Change for Bomber 58

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Maintaining the Marzocchi Bomber 58 suspension fork is essential for optimal performance and longevity. An oil change is one of the most crucial maintenance tasks for this fork model, as it ensures smooth damping, improved control, and proper functioning of the internals. In this guide, we’ll walk you through the steps to change the oil in the Bomber 58 fork, ensuring you get the most out of your suspension.

Tools Required

  • 8mm and 10mm wrenches
  • Suspension fluid (recommended by Marzocchi for Bomber 58)
  • Oil syringe or pump
  • T25 and T30 Torx wrenches
  • Small flathead screwdriver
  • 4mm Allen wrench [paid link]
  • Clean rags
  • Drain pan or container for old oil
  • Torque wrench [paid link]
  • A soft brush (optional for cleaning)
  • Gloves (optional but recommended)

Preparing for the Oil Change

Before starting the oil change, ensure that you have all the necessary tools and suspension fluid. Having the correct oil is vital to ensure proper damping performance. Also, it’s best to work in a clean, dry area to avoid contaminating the suspension internals.

Step 1: Removing the Fork from the Bike

  • Start by removing the fork from the bike. This can usually be done by loosening the bolts on the headset and carefully lifting the fork out.
  • Place the fork on a clean surface, preferably on a work stand, to prevent damage while you work on it.

Step 2: Removing the Fork’s Top Cap

  • Use a 10mm wrench to loosen and remove the top cap from the fork. This will give you access to the internals of the fork.
  • If your fork is equipped with a rebound adjuster or other top-mounted controls, carefully remove them before unscrewing the top cap.

Step 3: Draining the Old Oil

  • Once the top cap is removed, invert the fork over a container to drain the old oil. You may need to gently compress the fork to allow the oil to flow out completely.
  • Let the fork drain for several minutes to ensure all the oil has been removed.

Step 4: Disassembling the Fork

  • After draining the oil, proceed with removing the lower legs. Use a 10mm wrench to remove the bolts that secure the lower legs to the upper stanchions.
  • Gently slide the lower legs off, taking care not to damage the seals. If necessary, use a small flathead screwdriver to pry off any stubborn seals.

Step 5: Cleaning the Internal Parts

  • Use a clean rag to wipe down all internal parts, such as the stanchions, and the inside of the lower legs. This helps to prevent debris from contaminating the new oil.
  • Optionally, you can use a soft brush to clean out any dirt or grime that may have built up during use.

Refilling with New Oil

Step 6: Preparing the New Oil

  • Check the recommended oil type and amount for your specific Bomber 58 model, as Marzocchi offers various suspension fluid types for different performance characteristics.
  • Using an oil syringe or pump, prepare the new suspension fluid for installation.

Step 7: Filling the Damper Side with Oil

  • Locate the damper side of the fork. Insert the syringe or pump into the oil port and slowly fill the damper side with the recommended amount of oil.
  • Make sure not to overfill, as this can lead to air bubbles in the fork, reducing its performance.

Step 8: Filling the Air Spring Side with Oil

  • Similarly, fill the air spring side with the recommended amount of oil. This oil is crucial for the proper functioning of the air spring, providing consistent pressure and ensuring smooth fork movement.
  • Again, avoid overfilling.

Step 9: Reassembling the Fork

  • Carefully slide the lower legs back onto the upper stanchions, ensuring that the seals are seated correctly.
  • Tighten the bolts to secure the lower legs in place using a torque wrench [paid link] to the manufacturer’s specified torque setting.

Step 10: Reinstalling the Top Cap and Adjustments

  • Reinstall the top cap and any other components, such as the rebound adjuster, that were removed earlier.
  • Ensure everything is tightened to the correct torque settings. Double-check the adjustment controls to make sure they’re functioning smoothly.

Troubleshooting Common Issues

While changing the oil in your Bomber 58 fork is a straightforward process, issues may arise. Below are a few troubleshooting tips for common problems:

Fork Not Holding Air

  • If the fork isn’t holding air pressure after an oil change, check for damaged seals or improperly tightened bolts. Replacing worn seals and tightening components properly can resolve this issue.

Fork Feels “Squishy” or Has Reduced Damping

  • This could be a sign of insufficient oil in the damper side or air spring. Recheck the oil levels and ensure the fork is filled according to the manufacturer’s guidelines.
  • If the problem persists, inspect the internal components for wear or damage.

Oil Leaking from the Fork Seals

  • Leaks are typically caused by worn or improperly seated seals. If you notice oil leaking from the lower legs, remove the seals, clean the area, and replace the seals if necessary.

Customization and Optimization for Better Performance

After performing an oil change, it’s a good idea to optimize your fork for specific riding conditions or personal preferences.

Adjusting the Rebound and Compression

  • Marzocchi’s Bomber 58 suspension fork offers various adjustment options, including rebound and compression settings. Adjust these controls according to your riding style and terrain.
  • For smoother rides on technical trails, a slower rebound setting may offer more control. For faster, less technical terrain, try increasing the rebound speed.

Changing the Air Spring Pressure

  • Depending on your weight and riding style, you might want to adjust the air spring pressure for improved performance. Ensure you follow the recommended air pressure chart from Marzocchi for the best results.

Compatibility with Other Drivetrain Components

The Bomber 58 fork is compatible with a wide range of drivetrain components, but it’s crucial to check compatibility before installation. The fork’s axle standard, travel length, and brake mount configuration should align with your frame and wheels. Additionally, make sure the fork’s travel doesn’t interfere with other components like the bottom bracket or head tube.

Conclusion

Changing the oil in your Marzocchi Bomber 58 suspension fork is an essential maintenance task that ensures optimal performance and extends the life of your fork. By following the steps outlined in this guide, you can easily complete the oil change, troubleshoot common issues, and optimize your fork for various riding conditions. Regular oil changes will help maintain the damping performance and responsiveness of your suspension, ultimately providing a smoother and more controlled ride.