Original MTD extension (deck tension) spring 732-04099 — a direct-fit replacement that restores proper belt tension and deck engagement on compatible riding mower decks.

This is a heavy-duty extension spring with a free length of about 215 mm and an outside diameter of roughly 32 mm (active coil length ≈161 mm), built to the same spec used on MTD cutting decks.

Example models that use this spring include several MTD/ Cub Cadet / Bolens riding-tractor decks such as MTD JE 135 A (2004–2007 series), JE 145 A, JN 150 A and comparable Cub Cadet/Bl models — confirm your deck parts diagram shows part number 732-04099.

This part also replaces related reference numbers used in some parts lists (for example 732-0594A / 932-0594A), so it’s a suitable swap where those numbers are shown.

Buy with confidence if you need a genuine MTD deck-tension spring to get your mower back to cutting properly — it’s listed among MTD parts and kept to original specifications. Note: this is a replacement component commonly stocked alongside other small parts for power tools and garden machinery.