Replaces Spindle Assembly for Cub Cadet MTD 618-04125A 618-04126A 918-04125B 918-04126 918-04126B 618-04126 918-04126A and 918-04125A

What It Is

This is a replacement spindle assembly for the cutting deck of Cub Cadet and MTD lawn tractors. It houses the bearings and pulley that spin the mower blade, and is designed for residential or light commercial use.

Fitment & Compatibility

Before buying, verify your mower’s deck size and model number. This spindle replaces OEM numbers 618-04125A, 618-04126A, 918-04125B, 918-04126, 918-04126B, 618-04126, 918-04126A, and 918-04125A. It fits most 42-inch, 46-inch, and 50-inch decks on Cub Cadet, MTD, Troy-Bilt, and Yard Machines tractors with a 1-inch shaft diameter and a 3/8-inch bolt hole for the blade. Measure your existing spindle’s shaft length (typically 2-3/4 inches) and mounting hole spacing (usually 3-1/4 inches center-to-center) to confirm. If your deck uses a different shaft diameter or bolt pattern, this assembly won’t work.

Key Things to Know

• Quality: Aftermarket part with solid reviews (4.6/5), but it may not include a blade bolt or dust cap. Reuse your old hardware if needed.
• Installation: Moderate difficulty. You’ll need a socket set, a torque wrench (blade bolt to 40-50 ft-lbs), and possibly a puller to remove the old spindle. Plan for 30-60 minutes per spindle.
• Gotcha: The pulley may be pre-installed, but check that it’s tight. Some users report the pulley nut loosening after a few hours—use thread locker if not already applied.
• Bearings: Sealed bearings are included, but they are not serviceable. If they fail, you replace the whole assembly.

Should You Buy It

If your deck spindle is wobbling, noisy, or the blade won’t spin freely, this is a cost-effective, reliable replacement for most Cub Cadet and MTD residential mowers. It’s a good choice for DIYers comfortable with basic mechanical work, but if your deck uses a different shaft size or you want OEM-only parts, verify fitment first.