Gravely ZT-XL 52 (Residential Zero-Turn) Blade Bolt Torque

The blade bolt torque on the Gravely ZT-XL 52 (Residential Zero-Turn) is 80–120 lbf-ft (108–163 N·m), using a 5/8" hex bolt. Gravely ZT XL Owner/Operator Manual 00698300A (models incl. 915082 ZT2552XL 52"), p.GB-17, Install: "Torque 5/8-inch hex bolt to 80 to 120 lbf-ft (108 to 163 N•m)." Identical wording in the later ZT XL manual 04052400 (p.GB-19). The current-generation ZT X/XL manual 05278700B prints no blade torque at all, so nothing newer supersedes this. 5/8" is the bolt diameter, not a socket size; pitch and socket are not stated.

What's the exact spec for the Gravely ZT-XL 52 (Residential Zero-Turn)?

Torque: 80–120 lbf-ft (108–163 N·m). Thread: 5/8" hex bolt. Threadlocker: Not called for in the Gravely manuals cited below. Gravely ZT XL Owner/Operator Manual 00698300A (models incl. 915082 ZT2552XL 52"), p.GB-17, Install: "Torque 5/8-inch hex bolt to 80 to 120 lbf-ft (108 to 163 N•m)." Identical wording in the later ZT XL manual 04052400 (p.GB-19). The current-generation ZT X/XL manual 05278700B prints no blade torque at all, so nothing newer supersedes this. 5/8" is the bolt diameter, not a socket size; pitch and socket are not stated.

Step-by-step Gravely ZT-XL 52 (Residential Zero-Turn) blade-bolt reinstall

1) Disconnect the spark plug and engage the parking brake. 2) Block the blade with a 2×4 wedged against the deck shell — never your hand. 3) Use a 1/2" drive breaker bar with an impact socket sized to the blade bolt to break the bolt loose. 4) Clean threads with brake cleaner and inspect the bolt for stretch. 5) Reinstall with no threadlocker. 6) Torque to 80–120 lbf-ft (108–163 N·m) in one smooth pull with a calibrated torque wrench. 7) Re-check after the first hour of cutting.

Common Gravely ZT-XL 52 (Residential Zero-Turn) blade-bolt mistakes

Over-torque past spec stretches the bolt past yield — it will not hold the next reinstall. Under-torque lets the blade walk loose at full RPM, which destroys the spindle key and balance. Using a 12-point socket on a rusted bolt rounds the head; always use 6-point. The Pro-Turn manual cautions that mating surfaces between spindle, lower spindle guard, blade and washer "MUST be free of debris to ensure correct tightness and alignment" — clean them before torquing, or the 115–160 lb-ft reading is meaningless.

What socket fits the Gravely ZT-XL 52 (Residential Zero-Turn) blade bolt?

A 6-point impact socket sized to the blade bolt — the manual doesn’t state an exact size, so confirm it against the bolt head before buying one on a 1/2" drive breaker bar. A 12-point socket can be used in a pinch on a clean, sharp-edged bolt head — never on a rusted bolt.

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