Replace Fork Seals
The fork of a motorcycle connects the main frame to the front wheel and axle. The fork is what allows riders to change direction and also helps in braking and suspension. The fork itself consists of two tubes. Each tube requires a seal to keep the oil of the interior of the tube from leaking out. Fork seals should be replaced as soon as leaking oil is noticed. If the seal is left unchanged, the oil could leak onto the brake pads and ruin your motorcycle or you could run out of oil completely and ruin your motorcycle. Use these steps to replace your fork seals.
Steps
- Prepare the motorcycle for maintenance.
- Loosen the 2 bolts that secure the fork legs to the frame and the caps upon each leg. Then loosen the brake caliper bolts and the whole front axle of the bike.
- Put the bike in gear and chock the rear wheel.
- Raise the front wheel off the ground as far as needed.
- Remove the brake calipers, fender, front wheel and any other hanging cables.
- Disassemble the fork.
- Loosen the bolts further and pull downward on the fork while twisting.
- Remove the fork cap carefully. Because it is spring loaded, be careful not to stand in the way of the cap as you remove it.
- Take out the spring and let the oil drain into a bucket
- Free the damper rod by inserting a tool into the cavity to reach it.
- Memorize the assembly of the fork's springs, washers and spacers for easy re-installation later.
- Remove the old seal.
- Wedge the dust seal from the fork leg.
- Find the fork seal itself. It is held into place by a clip within a groove.
- Pry the seal out carefully.
- Flush the area as you go to remove debris within the fork.
- Take the tube in 1 hand and the stanchion in the other. Use muscle to pull the 2 apart. You will see the seal coming out of hiding as you do this.
- Prepare the fork for a new seal.
- Remove all rust and repair imperfections that led to the old seal's leakage.
- Soak a cloth with oil and work on the area where the seal rested.
- Install the new seal.
- Rub oil on the inner part of the new seal.
- Put the seal over the stanchion and slide it down into place.
- Set the seal with a seal driver. This will tap the seal into place gently but firmly.
- Put the fork back together.
- Situate the clip and dust seal back onto the fork. Place the damping rod back inside.
- Pour new oil into the fork, measuring the height as necessary.
- Re-install the spring and screw on the fork cap. Tighten the bolts.
- Repeat the process on the other fork leg.
- Reassemble your motorcycle's front end.
Tips
- Replace both seals at the same time regardless if only one needs to be replaced. This keeps the seals similarly aged.
- Instead of using physical force to separate the inner tube from the fork to remove the seal, you can fill the tube full of oil and add pressure to burst the seal out.
- Using a front-end lift is the safest way to raise your motorcycle for maintenance.
- The leg might need to be replaced if you cannot repair the damage hidden by the old seal.
Things You'll Need
- Motorcycle
- Sockets
- Ratchets
- Fork oil
- Wrenches
- Floor jack or lift
- Oil container or bucket
- Seal drivers
- Rags
- New seals
