Note on numbering: 7156579 is the Bobcat cylinder assembly number — “Cylinder, 331/430 Boom Assembly” per the official Bobcat EU parts catalog, which lists it for models 231, 329, 331, 334 and 430 (Mini Excavators). The reseal kit for this cylinder is commonly listed by aftermarket suppliers as 7156581 for Bobcat 331, 331E, 334 and 430 (HydraulicCylindersInc, ReliableAftermarketParts). This listing uses 7156579 as the reference for the boom cylinder reseal kit — if your records show 7156581, it is the same application.

The boom cylinder holds the entire front linkage during excavation, so seal wear shows up as boom drift, external leakage and reduced lifting capacity. The kit matches a 1-3/4″ (44.45 mm) rod × 3-1/4″ (82.55 mm) bore cylinder; typical contents include rod seal, piston seal, wiper, O-rings and backup rings. Confirm the exact component list with our sales team at [email protected].

The boom circuit holds sustained pressure — also check the counterbalance/holding valves before blaming the seals.

Factory-direct supply for distributors, repair shops and fleet operators. Wholesale MOQ: 5 kits. Email [email protected] with your quantity, shipping port and destination for a same-day quote. Custom packaging and private labeling available.

Why do I see both 7156579 and 7156581? — 7156579 is the Bobcat boom cylinder assembly number (official parts catalog); 7156581 is the seal kit number used by aftermarket suppliers to reseal that cylinder. This listing is the reseal kit.

Does the cylinder 7156579 also fit the 231 or 329? — Per the official Bobcat EU catalog, cylinder assembly 7156579 covers models 231, 329, 331, 334 and 430. Kit listings for 7156581 cover 331, 331E, 334 and 430 — confirm with your machine.

Is this a genuine Bobcat part? — No — this is a new aftermarket seal kit. If you need the Bobcat cylinder assembly itself, contact your Bobcat dealer.