How to Install a Variable Speed Belt on a Riding Mower

Disengage the PTO lever just as you do when turning off your mower deck after you finish mowing. Some mowers have a PTO switch instead of a manual lever. This stops the mower blades from spinning.

Drive your lawn tractor to flat stable ground, set the parking brake and then turn off the ignition key. Remove the ignition key to prevent the mower from turning on while you work on it.

Lower the mower deck to its lowest position with the lift lever. In most cases, the lift lever extends from one side of the mower deck or extends up though one of the rear fenders.

Locate the hangers that suspend the mower deck onto the bottom of the lawn tractor. In most cases, you will see hairpin retaining clips holding the deck's brackets onto pins mounted to the underside of the deck. Remove the hairpins and lower the deck to the ground. In other cases, you will see bolts holding the front and rear brackets in place. Remove those bolts with a wrench and lower the deck to the ground. Since this process differs depending on the mower model, having your owner's manual will help since most manuals show you how to remove the deck.

Slide the deck forward and locate the PTO pulley mounted under the motor. In most cases, you must remove a bracket that keeps the belt secured to the PTO pulley. Use a wrench to remove the bolts that hold the bracket in place and then remove the bracket.

Pull the belt off the PTO pulley and then slide the mower deck out from under the lawn tractor.

Take a photograph of the belts on the mower deck or draw a diagram of how the belts route around the pulleys. This will ensure you get the new belts on correctly.

Pull the top "PTO" belt off the pulley system of the mower deck and discard the belt. Since you removed the belt from the PTO pulley, you will have a lot of slack in the belt, which makes removing it from the deck easy.

Locate the idler pulley for the "drive" belt. The idler pulley has a spring-loaded mounting bracket below it. If the bracket has a square hole in it, place a 3/8-inch ratchet driver into the hole, rotate the pulley away from the belt and then remove the belt from the pulley system. If the mounting bracket does not have a square hole, disconnect the spring from the bracket with a spring puller and then loosen the cap screws that hold the bracket in place with an Allen wrench. Once they are loosened, remove the drive belt.

Place the new drive belt onto the pulley system. Again, follow your photograph or diagram. Tighten the idler pulley back into place.

Place the PTO belt onto the mower deck and then slide the deck back under the lawn tractor.

Place the PTO belt over the PTO pulley and reconnect the guard to the PTO pulley.

Lift the deck up and mount it under the lawn tractor reversing the steps with which you disconnected it.