Step-by-Step: Rebuilding Your 36 E-MTB Factory GRIP2 Suspension Fork

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The Fox 36 E-MTB Factory GRIP2 [paid link] suspension fork is engineered to deliver exceptional performance for electric mountain bike (E-MTB) riders who demand superior control, durability, and responsiveness. Over time, like all suspension forks, the GRIP2 model requires maintenance to maintain its performance and ensure safety on challenging trails. This guide will take you through the process of rebuilding your 36 E-MTB Factory GRIP2 [paid link] suspension fork, from disassembly to reassembly, and provide essential maintenance tips.

Tools Required

Before beginning the rebuild, ensure you have the necessary tools on hand:

  • 8mm, 10mm, and 15mm wrenches
  • Torque wrench [paid link] with correct torque settings
  • Fox damper fluid (Fox 10wt)
  • Fox 20wt oil for the lower legs
  • Needle-nose pliers
  • Snap-ring pliers
  • Small screwdriver (flathead)
  • T27 and T30 Torx drivers
  • 5mm Allen wrench [paid link]
  • Seal driver tool
  • Clean rags
  • Suspension grease
  • Fork oil drain pan
  • Replacement seals and bushings (if necessary)

Step 1: Removing the Fork from the Bike

To begin the rebuild, you’ll need to remove the fork from your E-MTB.

  1. Remove the front wheel: Use a 15mm through axle wrench to take off the front wheel from the fork.
  2. Disconnect the brake caliper: Use a 5mm Allen wrench [paid link] to unbolt the brake caliper from the fork’s mounts. Secure the caliper out of the way to avoid damaging it.
  3. Remove the fork from the head tube: Loosen the headset stem bolts with a 6mm Allen wrench. Slide the fork out of the head tube. Keep the fork upright to avoid spilling any fork oil.
  4. Place the fork on a stable work surface: Position it securely to ensure it doesn’t tip over during the rebuild process.

Step 2: Disassembling the Fork

With the fork removed from the bike, you can begin disassembling the components.

  1. Drain the oil: Place the fork upside down into a drain pan to allow the oil to drain from both the lower legs. Let it sit for several minutes to fully drain.
  2. Remove the damper and air spring: Using the 8mm and 10mm wrenches, remove the top caps from the fork’s upper tubes. The air spring should come out first, followed by the GRIP2 damper. Use a T27 Torx driver to remove the damper mounting bolts, carefully pulling it out from the fork’s upper tube.
  3. Remove the fork lowers: Unscrew the four bolts (two on each lower leg) securing the lowers to the upper section. Use a T30 Torx driver for this step. Once the bolts are removed, gently pull the lower legs off, making sure not to damage the fork’s internal seals.
  4. Remove the seals and bushings: Use a seal driver tool and a small flathead screwdriver to carefully remove the internal seals and bushings from both the upper and lower sections of the fork. Replace any worn or damaged seals during reassembly.

Step 3: Cleaning the Fork

Thorough cleaning is crucial to prevent any dirt or debris from interfering with the fork’s performance.

  1. Clean the upper tubes: Use a clean rag to wipe the upper tubes, removing any dirt or debris. Pay special attention to the area around the seals.
  2. Clean the lowers: Clean the inside of the fork lowers with a rag, removing old oil residue and dirt. Make sure the area is dry before reassembly.
  3. Inspect the parts: Check the damper, air spring, seals, and bushings for wear. If any parts are excessively worn or damaged, they should be replaced before reassembling the fork.

Step 4: Rebuilding the Damper and Air Spring

With the fork thoroughly cleaned, you can now begin the rebuilding process, starting with the damper and air spring.

  1. Rebuild the damper: Apply Fox damper fluid (10wt) to the damper assembly, ensuring it is fully lubricated. Carefully reinsert the damper into the fork’s upper tube. Torque the mounting bolts to the specified value (usually around 10Nm) using a torque wrench [paid link].
  2. Rebuild the air spring: Apply suspension grease to the air spring’s seals before reinstalling it into the upper tube. Ensure that the air spring is properly seated and torqued to the manufacturer’s specifications.
  3. Check the air spring pressure: Before fully reassembling the fork, check the air spring pressure using a shock pump to ensure it meets your rider weight and riding preferences.

Step 5: Reassembling the Fork

After rebuilding the air spring and damper, you are ready to reassemble the fork.

  1. Install the lowers: Carefully slide the fork lowers back onto the upper legs, ensuring the internal bushings and seals are correctly aligned. Secure the lowers by tightening the four bolts to the correct torque specification.
  2. Install new seals: Use a seal driver tool to install the new seals into the fork’s upper tubes. Be sure the seals are seated properly to prevent oil leakage.
  3. Reinstall the top caps: Reinstall the top caps on the fork and torque them to the correct specifications. Ensure the air spring is properly seated and the damper is securely installed.
  4. Refill with oil: Add Fox 20wt oil to the fork lowers, following the manufacturer’s guidelines for the correct amount. Ensure the oil level is accurate to ensure proper performance.

Step 6: Final Adjustments and Testing

Now that the fork is reassembled, it’s important to test the suspension and make final adjustments.

  1. Set your sag: Use a shock pump to adjust the air spring pressure and set your desired sag based on your weight and riding style. A typical E-MTB rider’s sag is between 20-30%.
  2. Adjust the GRIP2 damper: Adjust the rebound and compression settings on the GRIP2 damper according to your personal preferences. The GRIP2 offers a wide range of tuning options, so experiment with different settings to find what works best for you.
  3. Test the fork: Perform a test ride to ensure the fork performs as expected. Check for any oil leaks, unusual noises, or abnormal behavior. Make further adjustments if necessary.

Step 7: Troubleshooting Common Issues

Here are some common issues you may encounter with the Fox 36 E-MTB Factory GRIP2 suspension fork, along with potential solutions:

  • Fork is too soft or too firm: If the fork feels too soft or too firm, adjust the air spring pressure. Ensure the recommended pressure for your rider weight is applied.
  • Excessive rebound or compression: If the fork rebounds too quickly or too slowly, adjust the rebound setting on the GRIP2 damper. Similarly, adjust the compression to tune the fork’s response.
  • Oil leaks: Oil leaks typically indicate a seal issue. Inspect the seals and replace them if necessary. Ensure the lowers are properly installed and torqued.

Step 8: Maintenance Tips

Regular maintenance will prolong the lifespan of your Fox 36 E-MTB Factory GRIP2 suspension fork and ensure optimal performance.

  • Clean and lubricate regularly: After each ride, wipe down the fork’s upper tubes and lubricate the stanchions with a light coating of suspension oil.
  • Service intervals: Perform a full rebuild of the fork every 100-150 hours of ride time or annually, whichever comes first.
  • Monitor performance: Pay attention to any changes in the fork’s performance, such as stiffness, noise, or handling, and address issues promptly.

By following these steps, you can rebuild and maintain your Fox 36 E-MTB Factory GRIP2 suspension fork, ensuring it performs at its best every ride.