Mower Deck Spindle Reinforcement Ring Mower Deck Spindle Repair Plate for John Deere 42" Mower D100 D140 D160 LA100 LA115 LA120 LA125 LA140 LA145 LA155 LA165 X110 X120 X140 L100 L110 2 Pack

What It Is

This is a steel reinforcement plate that bolts onto the underside of a John Deere mower deck to repair a worn or cracked spindle mounting hole. It prevents the spindle from loosening or shifting during operation, extending the life of decks on 42-inch Edge and Edge Xtra mowers.

Fitment & Compatibility

• Deck size: 42-inch (fits John Deere 42" Edge and Edge Xtra decks only—measure your deck width before ordering).
• Model series: D100, D140, D160; LA100, LA115, LA120, LA125, LA140, LA145, LA155, LA165; X110, X120, X140; L100, L110.
• OEM cross-reference: Replaces John Deere part numbers GY21137, GY20788, GY21136, GY21059. Not an OEM part—aftermarket steel, typically thicker than stock.
• What to measure: Spindle bolt hole pattern (center-to-center distance on the mounting flange). Most 42" decks use a 3.75" pattern, but verify yours by removing a spindle and measuring.
• Fitment check: If your deck has a stamped steel housing (not fabricated), this plate will work. Not for decks with oval or non-standard spindle holes.

Key Things to Know

• Installation difficulty: Moderate. You must remove the spindle, clean the deck surface, and bolt the plate between the deck and spindle. A socket set and torque wrench are needed.
• Quality: 4.6/5 stars across 28 reviews—users report solid steel construction and good corrosion resistance. Some note the plate is slightly thicker than OEM, which can require longer bolts (not included).
• Common gotcha: The plate adds ~1/8" thickness, so your spindle bolts may be too short. Plan to buy longer grade 8 bolts (typically 1/2" longer) if the originals don’t thread fully.
• Quantity: Sold as a 2-pack—ideal for replacing both spindles on a two-spindle 42" deck, but you can use one plate per damaged hole.

Should You Buy It

Buy this if your 42" John Deere deck has a worn or cracked spindle mounting hole and you want a cheap, durable fix instead of replacing the whole deck. It’s a solid choice for DIY repairs on older or high-hour mowers. Skip it if your deck is bent or rusted through—then a new deck is the better bet.