How to Install a Bearing on a Mandrel Shaft for a Mower

Cut two pieces of wood to the height of the deck of your mower, measured from ground level, using a circular saw. Prop one piece of wood under either side of the deck, to hold the weight of the deck. Pull out the cotter pins from the surface of the deck, using pliers. Pull the rods on the underside of the deck away from the deck.

Slide the drive belt off the motor pulley. Lift the deck off the mower and set it aside. Slide the drive belt out of the pulley system altogether, to allow access to the mandrel shaft. Unscrew the bolt holding the pulley with the damaged bearing on the mandrel shaft, using a wrench.

Hold a small piece of wood against the pulley. Tap the wood firmly with a hammer, to loosen the bearings. Remove both the upper and lower bearings in this manner. Sit a replacement bearing in the end of the pulley. Hold the old bearing against the new bearing. Tap the old bearing with a hammer to drive the new bearing into the pulley. Repeat with the other bearing.

Screw the pulley back onto the mandrel shaft, using the restraining bolt you removed earlier. Slide the drive belt back onto the pulleys so it sits in the same position as it did when you first accessed it. Slide the drive belt back onto the motor pulley. Place the deck back on top of the mower. Push the rods back into place under the deck. Re-pin the deck to the mower using the cotter pins.