How to Replace the Spur Gear on a Porter-Cable Belt Sander

Your belt sander has a gearbox that creates additional torque and optimizes the belt speed. The gearbox is driven by a belt between the motor and the gearbox. There are two gears in the gearbox. This article describes the process of replacing the spur gear. All gears will wear after years of use. Heavy use will wear the gears faster. Symptoms of worn gears are increased gear noise or a ticking sound from the gearbox. When a gear fails, the motor will run, but the sanding belt will not move (or the belt will stop moving as soon as the sander is placed on a work piece).

Let's get started.

REMOVING THE SPUR GEAR   1. Remove the belt cover.

a. Remove the screws securing the belt cover to the side of the sander.

b. Remove the belt cover from the sander.

  2. Remove the lower belt and pulley.

a. Insert long-nosed pliers into the slots beside the (center) hex nut. This will prevent the pulley from rotating during removal.

b. Use a hex wrench to remove the screw securing the pulley to the shaft. The hex screw is reverse-threaded (requiring clockwise rotation to loosen).

c. Remove the lower belt pulley and the drive belt from the sander.

  3. Remove the gearbox cover.

a. Remove the four screws securing the gearbox cover to the sander.

b. Remove the gearbox cover.

  4. Remove the spur gear.

a. Use a socket ratchet/wrench to remove the nut securing the spur gear to the spindle.

b. Use long-nosed pliers to lift the spur gear out of the gear box.

INSTALLING THE NEW SPUR GEAR

  5. Install the spur gear.

a. Place the new spur gear onto the shaft.

b. Align the keyway in the gear with the key on the shaft and insert the gear into the gearbox.

c. Secure the gear with the nut.

REASSEMBLING THE UNIT

  6. Reinstall the gearbox cover.

a. Install the gearbox cover.

b. Secure the gearbox cover with the four screws.

  7. Reinstall the belt and pulley.

a. Align the belt with the cogs on the upper pulley.

b. Align the belt with the cogs on the lower pulley.

c. Install the lower pulley onto the spindle.

d. Secure the lower pulley with the hex screw. (The screw is reverse-threaded.)

  8. Reinstall the belt cover.

a. Install the belt cover.

b. Secure the belt cover with the screws.