M143350 M111358 M146073 M131119 24H1184 T40189 M122350 Deck Idler Arm Ternsioner & Bushing Rebuild Kit fits John Deere 48C 54C GT LX GX Scotts Sabre Tractor Lawn Mowers Used with AM37249 Pulley

What It Is

This rebuild kit replaces the deck idler arm tensioner and bushing assembly on 48- and 54-inch mower decks (models 48C, 54C) for John Deere GT, LX, GX, Scotts, and Sabre lawn tractors. It restores proper belt tension to the blade drive system, preventing belt slip and uneven cutting.

Fitment & Compatibility

Before buying, confirm your deck model and mower brand. This kit fits John Deere 48C and 54C decks on GT, LX, GX, Scotts, and Sabre tractors. It replaces OEM part numbers M143350, M111358, M146073, M131119, 24H1184, T40189, and M122350. It works with the AM37249 pulley (sold separately). Measure your existing arm’s pivot bolt diameter—this kit uses a 5/16-inch bushing. Check that your deck has a single idler arm (not a dual-arm setup). Not compatible with 42-inch or 60-inch decks.

Key Things to Know

• Quality: Kit includes a steel idler arm, nylon bushing, and retaining hardware. The bushing is greasable—apply light grease during installation to extend life.
• Installation difficulty: Moderate. You’ll need a socket set and a breaker bar for the pivot bolt. Expect 30–45 minutes. No special tools required.
• Common gotcha: The bushing can be pressed in too tight—leave a slight gap (1/16 inch) between the arm and deck bracket for free movement.
• Belt routing: After replacing, verify belt tension and routing. A loose belt will cause the new arm to wear quickly.

Should You Buy It

If your 48C or 54C deck idler arm is worn, has play, or the belt keeps slipping, this kit is a solid, low-cost fix. It’s well-reviewed (4.9/5 stars) and restores OEM-level performance for under $16. Avoid if your deck uses a different arm style or if the pulley itself is damaged (you’ll need the separate AM37249 pulley).