42 Inch Mower Deck Rebuild Kit for John Deere D100 D105 D110 D130 LA100 LA105 LA110 LA115 LA120 LA125 LA135 Parts Spindle GY21098 Blade GY20850 Idler Pulley GY20110 GY20067 GX20367 Belt GX20072

What It Is

This is a complete 42-inch mower deck rebuild kit for select John Deere 100 and LA series lawn tractors. It includes four spindles, one blade, two idler pulleys, and a drive belt—everything needed to refresh a worn-out deck in one purchase.

Fitment & Compatibility

Verify your deck size first: This kit fits only 42-inch mower decks (stamped on the deck shell). Compatible with John Deere D100, D105, D110, D130, LA100, LA105, LA110, LA115, LA120, LA125, and LA135 models.
OEM cross-reference: Spindle GY21098, blade GY20850, idler pulleys GY20110 and GY20067/GX20367, belt GX20072.
Before buying: Measure your existing belt length (should be ~92.5 inches) and spindle bolt pattern (3-bolt, 4-inch spacing). Check that your blade is 42-inch (not 46-inch or 48-inch). This kit is aftermarket, not genuine John Deere—quality is generally good but tolerances can vary slightly.

Key Things to Know

• Installation difficulty: Moderate (4/10). Requires basic hand tools (socket set, jack stands, impact wrench helpful). Expect 1.5–2 hours for a full rebuild.
• Spindle quality: Aftermarket spindles are steel, but some users report slightly shorter bearing life than OEM. Grease them before installation and re-grease every 25 hours.
• Belt fit: The GX20072 belt is a standard replacement—check tension after installation; a loose belt causes slippage and poor cutting.
• Missing blade: Kit includes only one blade (driver’s side). You’ll need a second GY20850 blade for the other side unless you replace both with a matching set.

Should You Buy It

Buy this kit if your 42-inch John Deere deck has noisy spindles, a slipping belt, or uneven cutting and you want a single-box solution to restore performance. It’s a solid value for DIY homeowners who can handle basic wrenching. Skip it if you need genuine OEM parts (for warranty or high-use commercial mowing) or if your deck is over 10 years old and may have structural rust or weld cracks.