2 Pcs Mower Deck Belt Tension Spring GX21582 GX20377 Fits for John Deere L120 L130 D140 D150 D155 D160 D170 G110 LA130 LA140 LA150 LA155 LA165 LA175 L2048 L2548 X140 145 165 Sabre 1642HS 1742HS

What It Is

This is a pair of replacement deck belt tension springs (OEM cross-refs GX21582 and GX20377) for select John Deere lawn tractors and Sabre models. They maintain proper tension on the mower deck drive belt, preventing slipping or premature wear during cutting.

Fitment & Compatibility

Before buying, verify your mower’s model number (e.g., L120, D140, X140) and deck size—these springs fit 42-inch, 48-inch, and 54-inch decks on compatible tractors. Check your existing spring’s length (typically ~4.5 inches fully extended) and hook type (closed loop at both ends). This aftermarket set is a direct replacement for OEM parts GX21582 and GX20377, but confirm your deck’s spring mount points match the same spacing (about 3.5 inches center-to-center). Not compatible with older or non-Deere decks without cross-referencing.

Key Things to Know

• Quality: At $7.89 for two, these are budget-grade. Expect adequate tension but may have slightly less corrosion resistance than OEM; inspect annually for rust.
• Installation: Easy—use a spring puller or pliers to remove the old spring and hook the new one onto the same anchor points on the deck and idler arm. No special tools needed.
• Common gotcha: If your deck has two springs (one per side), replace both at once to ensure even tension. A weak spring can cause belt slipping or uneven cutting.
• Note: If your belt is also worn, replace it simultaneously to avoid over-stressing the new springs.

Should You Buy It

This is a solid budget pick for owners of listed John Deere or Sabre models who need a quick, low-cost fix for a sagging or broken deck tension spring. It’s not premium, but works fine for typical residential mowing. Skip it if you want heavy-duty or salt-spray-resistant parts—pay more for OEM or coated options.