2 Pack 918-05078A Spindle Assembly with 756-05034A 756-04511B Idler Pulley 954-04325 Belt for Cub Cadet RZT L46, RZT S46, RZT LX46, RZT SX46, Troy Bilt Mustang XP 46, Craftsman Z6400 46" Deck

What It Is

This is a replacement spindle assembly kit for 46-inch zero-turn mowers, including two spindles, two idler pulleys, and a drive belt. It’s designed for Cub Cadet, Troy Bilt, and Craftsman models with a 46-inch fabricated deck—ideal for restoring cutting performance when blades wobble, the deck vibrates, or the belt slips.

Fitment & Compatibility

Before buying, confirm your mower’s deck size is exactly 46 inches (measure deck shell width, not blade span). This kit fits Cub Cadet RZT L46, RZT S46, RZT LX46, RZT SX46, Troy Bilt Mustang XP 46, and Craftsman Z6400 46” deck. Check your model’s serial number prefix—these use stamped steel spindles (OEM part 918-05078A) with a 5/8-inch shaft. The belt (954-04325) is a 1/2-inch x 107-inch Kevlar-reinforced replacement. Not for older models with aluminum spindles or 48/50-inch decks. Verify your deck pulley configuration (2-spindle, single-belt system) before ordering.

Key Things to Know

• Quality: OEM-equivalent spindles with sealed bearings—longer life than generic no-name parts. Idler pulleys (756-05034A, 756-04511B) are steel, not plastic.
• Installation: Moderate difficulty. Requires removing deck, loosening belt tension, and swapping spindles. You’ll need a 15mm socket, torque wrench (spindle bolts to 35-40 ft-lbs), and thread locker.
• Common gotcha: The belt may be slightly tight on some decks—check pulley alignment after install. If blades don’t spin freely, re-center the belt on idlers.
• Pack contents: All parts needed for a full spindle/pulley/belt swap—no extra hardware or blade replacements included.

Should You Buy It

If your 46-inch Cub Cadet, Troy Bilt, or Craftsman zero-turn has worn spindles (wobble, noise) or a frayed belt, this all-in-one kit saves time and shipping cost vs. buying parts separately. It’s a solid value for DIY owners who want OEM-level durability without dealer markup.