HD Switch - Deck Belt Pulley Idler Arm Tensioner, Bushing & Hardware Kit fits John Deere 180 240 245 260 265 320 325 335 345 355D Tractor Lawn Mowers

What It Is

This HD Switch idler arm tensioner kit replaces the spring-loaded pulley assembly that maintains belt tension on the mower deck’s drive system. It’s designed for select John Deere 100–300 series tractors with 38–48 inch decks.

Fitment & Compatibility

Check your model number (e.g., 180, 240, 260, 265, 320, 325, 335, 345, 355D) and deck size—this kit fits 38", 42", 44", and 48" decks on those tractors. It replaces OEM part AM34507 and includes the idler arm, bushing, hardware, and pulley. Measure your existing pulley diameter (typically 3.5") and bushing inner diameter (0.5") to confirm match. Aftermarket, not OEM—verify belt routing diagram matches your deck.

Key Things to Know

• Quality: Bushing is sintered bronze (self-lubricating), but check for burrs on the arm edge—file smooth if needed.
• Installation: Moderate difficulty (30–60 minutes). Need a wrench set, socket, and pry bar to relieve belt tension. Watch for worn spindle bearings that could cause premature failure.
• Common gotcha: The included bolt may be slightly longer than OEM—use the original hardware if the new bolt bottoms out in the deck frame.
• Belt compatibility: Works with standard A-section belts (1/2" wide)—ensure belt length matches your deck (common sizes: 92", 96", 100").

Should You Buy It

This kit is a solid budget fix if your deck belt slips, squeals, or the idler pulley wobbles, but only for the listed John Deere models. Skip it if you need OEM exact fit or have a different deck size—measure first. For $22, it’s a practical repair for DIYers with basic tools.