DIY: How to Replace the Deck Belt on an MTD Mower

The MTD Yard Man riding mower with a 27.5-inch cutting deck is a compact, well-designed mower suited for medium to large yards. The internal bagging system reduces down-time, and its zero-turn concept makes it easy to handle in tight corners. Although the machine is fitted with three belts, the lower and upper drive belts are protected from debris kick-back and last for extended periods before wearing out. The deck belt, on the other hand, must be replaced periodically.

Set of socket wrenches
New mower deck belt

Instructions

- 1
  Drive the mower onto a clean, flat surface and remove the ignition key. Pivot the mower cover containing the seat up and forward. Unhook the grass catcher from the back of the mower and lay it aside.
- 2
  Pull the rubber boot from the spark plug and secure it away from the plug. Lower the deck by setting the mower cutting height lever to its lowest position.
- 3
  Remove the hex nut and lock washer holding the right side of the tubular belt guard to the rear of the mower; use a 7/16-inch socket wrench fitted to a 6-inch extension to reach the nut. Undo the 3/8-inch self-tapping bolt holding the opposite side of the guard to the chassis with a socket wrench. Push the belt guard forward and out of the way.
- 4
  Work from the top-left side of the mower and undo the three self-tapping bolts and lock washers holding the deck belt cover to the deck with a 1/2-inch socket wrench. Lift the belt cover off and lay it aside.
- 5
  Loosen the hex nut on the center of the spring-loaded idler pulley with a 9/16-inch socket wrench to relieve tension on the belt; the idler pulley rests against the right side of the belt between the mower blade shaft and the chassis.
- 6
  Slip the worn deck belt from around the engine pulley, the idler pulley and the deck pulley. Lift the belt out from between the belt keeper and the idler pulley and discard it.
- 7
  Loop a replacement belt around the deck pulley and engine pulley, with the V section of the belt fitting into the matching groove in both pulleys. Slide the belt between the belt guard and the idler pulley, with the outer flat side of the belt resting against the flat face of the idler pulley.
- 8
  Align the belt guard parallel with the belt and tighten the central idler pulley hex nut loosened earlier with a 9/16-inch socket wrench.
- 9
  Lower the deck belt cover back into place, and ensure that the second belt keeper attached to the underside of the deck belt cover straddles the belt while doing so. Insert the three 1/2-inch self-tapping bolts removed earlier and tighten them securely with a socket wrench.
- 10
  Bolt the belt guard back onto the rear of the mower with the 3/8-inch self-tapping bolt removed earlier. Replace the 7/16-inch nut and lock washer removed earlier, and tighten both the nut and the self-tapping bolt securely with a socket wrench.
- 11
  Slot the grass catcher back into place on the back of the mower, and lower the mower cover containing the seat to complete the installation

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