UDC Parts Spindle Assembly for Troy-Bilt 46-inch Deck — Complete Direct-Fit Replacement Kit

UDC Parts 918-06989 is a complete spindle assembly engineered to replace worn or damaged spindles on 46-inch Troy-Bilt and compatible MTD decks, restoring cutting performance and deck reliability.

When a mower deck starts vibrating, cutting unevenly, or producing unusual noises, the spindle assembly is often the root cause. This UDC Parts spindle is manufactured as a direct-fit replacement for OEM numbers MTD 618-06989 and 918-06989 and comes as a ready-to-install kit that includes the spindle, mounting hardware, blade bolt, pulley nut, and washer. Built from robust materials, it’s intended to withstand regular lawn care demands while returning your deck to stable, true rotation.

How will this spindle assembly improve my mower’s cutting performance?

Replacing a worn spindle reduces blade wobble and uneven blade pitch, which restores a consistent, level cut across the 46-inch deck. The included pulley and nut ensure proper belt alignment so the blade spins smoothly at designed RPMs.

• Replaces OEM numbers MTD 618-06989 and 918-06989 for exact fit.
• Restores correct pulley diameter and alignment for belt tension.
• Reduces vibration and improves blade stability for cleaner cuts.
• Complete kit means fewer return trips to the parts store.

What comes in the kit and what sizes should I expect?

The assembly ships with everything required to swap spindles on compatible decks: one spindle unit, four mounting bolts, one blade mounting bolt, one pulley lock nut, and a washer. The spindle’s dimensions and pulley sizing match OEM specifications so existing blades and belts remain compatible.

• Spindle height: 6-7/8" to match deck clearance requirements.
• Pulley outer diameter: 6-1/4" to preserve belt geometry.
• Six-point star pattern on the pulley for secure belt seating.
• Hardware included for a single-spindle replacement—no extra parts needed.

Which mower models and brands will this part fit?

This spindle assembly is designed for a broad range of Troy-Bilt and MTD family machines with 46-inch decks, covering Bronco and Horse series variants and many model numbers specified by MTD. Confirm your mower’s OEM part number or model list before ordering to ensure compatibility.

• Fits Troy-Bilt: Bronco 46 Auto/46B/46T/46X and Horse series (Hydro, XP, Auto).
• Replaces part used on MTD model families including T1500, T1600, T1700, T1900, T2600, T2700.
• Compatible MTD part numbers include 247.27343, 247.27372, 247.25586 and similar listings.
• Also fits models labeled CLT46CVT, LT 4600, and many CMXGRAM variants listed by MTD.

How difficult is installation and what tools will I need?

Installation is straightforward for someone comfortable with basic mower maintenance: lift and secure the deck, remove the old spindle assembly and transfer blade and pulley as needed, then fasten the new spindle with the supplied hardware. Torque values and safety steps vary by mower—follow manufacturer instructions and use standard hand tools.

• Typical tools: socket set, torque wrench, jack or deck lift, safety gloves and eye protection.
• Use correct torque on bolts to prevent loosening under load.
• Inspect belts and blades during replacement; replace worn parts for best results.
• If unsure, consult a professional to avoid injury or improper installation.

Who this is for: Gardeners, lawn-care professionals, and DIY owners of Troy-Bilt or compatible MTD tractors with 46-inch decks who need a reliable, full hardware spindle replacement. If your deck shows vibration, uneven cutting, or you’ve confirmed the OEM numbers match 618-06989 / 918-06989, this UDC Parts assembly gives you a cost-effective way to restore deck function and extend the life of your mower.