How to Change the Fork Seals in Vehicles

by Contributing Writer; Updated June 12, 2017

Keeping your Vehicles in its peak operating condition requires much more than an oil change every now and then. A watchful eye must be kept on the motorcycle's fork, which relies on an oil-damping system to compensate Vehicles changes in the road's surface. Although the Vehicles fork is fairly durable, the seals that keep the oil within the fork legs are susceptible to wear over time. A slick, oily film on the fork's tubes is the first sign of trouble. If you spot a leak, don't ride your motorcycle until the fork seals have been replaced.

Under The Hood:

 How to Change the Fork Seals in My Honda CRF450R

Place the bike lift under the engine and raise the 450R off the ground completely. The front forks must fully extend.

Loosen the two mounting clamps at the top of each fork using an Allen wrench. Pull forks from the clamps and lean the forks on the body of the 450R.

Place the blade of the screwdriver between the edge of the seal and the fork. Pry the fork seal off the fork but make sure you don't damage the fork. Pull the seal up and off the front forks.

Slide the new Honda 450R front fork seals down the forks. Force the seals into place on the forks using your hands. The seals will make snapping sounds when they lock into place.

Place the forks in the mounting clamps. Tighten the clamps using the Allen wrench.

Items you will need

  • Bike lift

  • 1/2-inch Allen wrench

  • Flat-head screwdriver

  • Replacement 450R fork seals

 How to Change Fork Seals on a Yamaha V Star 1100

Support the motorcycle on a service lift or jack. Remove the front brake caliper from the lower fork legs using a 12-mm socket and a socket wrench. Loosen the pinch bolt of the bottom of the right lower fork leg with a 12-mm socket wrench. Unscrew the front axle with a 17-mm socket, then pull it out from the front fork and wheel. Roll the wheel away from the motorcycle. Unscrew the front fender's bolts with a 10-mm socket, then remove the fender from the fork legs.

Remove one fork leg at a time. Loosen the pinch bolts on the upper and lower fork clamps using a 6-mm Allen wrench. Loosen the bolt on the rear of the forward turn signal assembly, positioned on the upper fork tube and just above the lower fork clamp, using a 10-mm socket. Pull the fork leg out from the bottom of the fork clamps and place it in a soft-jawed vise, facing the fork's top cap upward.

Unscrew the top cap from the upper fork tube using a 22-mm socket. Maintain a downward pressure on the the top cap to prevent it from being flung outward by the fork's internal spring. Remove the top cap and pull the cap's washer, the fork spring and the spring seat out of the upper fork tube.

Remove the fork leg from your vise. Hold the top of the fork tube over a container and pour out the fork's oil supply. Pump the fork tube repeatedly to force out any trapped oil. Place the lower fork leg horizontally into your vise.

Slide the fork spring into the fork tube, then loosely screw the top cap into place with a 22-mm socket. Push the fork tube into the lower fork leg and hold it in place. Unscrew the damper rod bolt, positioned at the bottom of the fork leg, using an 8-mm Allen wrench. Release the fork tube and remove the top cap and spring.

Pull the rubber dust boot off of the top of the lower fork leg and slide it off of the upper fork tube. Pry out the oil seal circlip from the top of the fork leg with a flat screwdriver. Remove the fork tube from the lower fork leg, using a back-and-forth motion to pull the tube, fork seal and damping rod out of the fork leg. Pull the seal off of the fork tube.

Coat the bottom of the fork tube with fresh 10W fork oil, then slide it into the lower fork leg. Reinsert the fork spring into the fork tube, then loosely screw the top cap into place with a 22-mm socket. Push the fork tube into the lower fork leg and hold it in place. Screw the damper rod bolt into the bottom of the fork leg using an 8-mm Allen wrench. Release the fork tube and remove the top cap.

Coat a new fork seal with 10W fork oil and slide it down the fork tube. Seat the fork seal with a seal driver, then slip the seal's circlip into place. Slide the rubber dust boot down the fork tube and onto the top of the lower fork leg.

Remove the fork leg from your vise, then pour up to 15.5 fluid oz. of 10W fork oil into the top of the fork tube. Screw the top cap into place with a 22-mm socket. Slide the fork tube up and through the motorcycle's fork clamps. Tighten the fork clamp pinch bolts with a 6-mm Allen wrench. Tighten the froward turn signal assembly's bolt with a 10-mm socket.

Replace the remaining fork's seal following the method shown above. Reinstall the fork leg. Reassemble the front wheel, brake calipers and fender in the reverse order of removal.

Items you will need

  • Service lift or jack

  • 10-, 12-, 17- and 22-mm sockets

  • Socket wrench

  • 6- and 8-mm Allen wrenches

  • Soft-jawed vise

  • Container

  • Flat screwdriver

  • 10W fork oil

  • Fork seals

 How to Change Fork Seals on a Harley

Lift the motorcycle using a motorcycle jack until the front wheel clears the ground. Ensure the motorcycle is securely tied down to the jack.

Remove the brake clevis pin at the brake lever, brake shoe anchor and centering bolt on motorcycles built before 1972. Remove the axle nut, fork slider cap nuts, speedometer cable and brake caliper on motorcycles built from 1973 on.

Push the axle out of the wheel using a hammer and drift. Remove the wheel from the front fork assembly, making sure not to lose any spacers from the wheel hub.

Remove the fork tube cap. The cap is under mild spring tension; use caution when removing the cap. Use the correct size socket on the cap to prevent damage to the nut.

Place a drain pan under the forks, and remove the fork slider lower bolt. Pull the fork tube out of the slider, and allow the fork oil to drain. The slider bolt is located at the bottom of the fork tube inside the axle saddle. Some models are equipped with a fork oil drain plug on the side of the slider tube near the axle. Discard the used fork oil in accordance with local disposal laws.

Remove the oil seal lock-ring using lock-ring pliers. Pry the oil seal out of the fork slider using a dull flat-tip screwdriver. Use caution that the inner and outer surface of the slider is not damaged when the seal is removed. Inspect the fork tube, fork slider tube and wheel assembly for damage. Repair or replace any damaged or worn-out parts as required.

Grease the outside of the new oil seal, and push the seal into the fork slider. Use a socket of the same size as the seal to help push it into the slider until it seats at the bottom of the seal well. Replace the oil seal lock-ring, and ensure it has snapped completely into the ring groove.

Slide the fork slider onto the fork tube, and fasten the original screw and washer. Tighten the fork slider screw to 11 ft-lbs.

Fill the fork tube with the correct amount and type of fork oil. Consult the manufacturer's specifications for specific information on your model of motorcycle. Pour the measured oil from a graduated measuring cup into the top of the fork tube with a funnel. Tighten the fork tube cap to 11 ft-lbs. using the correct size socket.

Reinstall the front wheel onto the fork sliders Push the front axle through the sliders and wheel hub, making sure that any spacers are reinstalled in the correct locations. Replace the brake clevis pin at the brake lever, the brake shoe anchor and centering bolt on motorcycles built before 1972. Replace the axle nuts, fork slider cap nuts, speedometer cable and brake caliper on motorcycles built from 1973 on. Tighten the axle nuts to 50 ft-lbs.

Items you will need

  • Motorcycle jack

  • Socket set

  • Hammer

  • Drift

  • Combination wrench set

  • Drain pan

  • Lock-ring pliers

  • Dull flat-tip screwdriver

  • Oil seal

  • Fork oil

  • Funnel

  • Graduated measuring cup

  • Torque wrench

 How to Change the Fork Seals of a CX500

Remove the front wheel from the motorcycle. Remove the two bolts holding the brake caliper to the fork and remove it. Tie up the caliper with wire to avoid tension on the brake line. Remove the front fender.

Loosen the upper triple clamp bolt. Loosen but do not remove the top fork cap. Loosen the lower clamp bolt, and slide the fork out. Hold the fork tube in a vise with soft jaws. Do not overtighten the vise to prevent bending the tube.

Remove the upper fork plug from the fork tube. Slide the spring out. Remove the fork from the vise, and turn it upside-down, pouring out the fork oil. Pump the fork by hand several times to ensure that most of the oil has been removed.

Clamp the fork base in the vise, and remove the Allen bolt at the bottom. Pull the fork tube out of the bottom case. Remove the dust seal from the bottom of the fork tube, then remove the clip that holds in the fork seal. Carefully pry the seal out of the lower half of the fork assembly, careful not to cause any damage. Clean all parts with solvent.

Using a fork seal driver, install the new seal in the lower half of the fork leg, spring side down. Replace the clip and dust seal. Use a new dust seal if the old one is cracked or damaged. Install the upper fork tube and parts into the fork. Screw on, but do not tighten the upper fork cap. Screw the Allen screw back into the bottom of the fork using a new copper washer.

Remove the cap and pour in the recommended amount of fork oil. Screw the cap back on, using a new O-ring. Install the fork in the triple clamps, tightening the lower bolt to specification. Tighten the fork cap to the proper specification before tightening the upper bolt to the proper specs.

Install the fender, the brake caliper and the front wheel. Torque all bolts to specs found in the manual. Pump the suspension a few times to ensure there are no leaks. Pump the front brake lever a few times to reseat the brake pads. Take the bike for a test drive, and check for leaks.

Items you will need

  • Basic metric tools

  • Allen wrenches

  • Fork seal driver

  • Copper washers

  • Fork oil