271-1717 CAT 992K Boom Lift Cylinder (LH) Aftermarket Replacement

Product Overview

SEIGO’s aftermarket boom lift cylinder, part number 271-1717, is a direct drop-in replacement for the left-hand lift cylinder on the Caterpillar 992K mining wheel loader — one of Caterpillar’s large production loaders, matched to load haul trucks in the 90-plus tonne class. Caterpillar catalogues this part as Cylinder Gp-Lift, LH, within the 346-1000 lift cylinder group, with a 279.4 mm (11 in) bore and a 1148 mm (45.2 in) stroke.

The 992K uses paired lift cylinders, one on each side of the loader linkage. The right-hand cylinder is 271-1716. Caterpillar has issued field-replacement numbers for both: 271-1717 (LH) is replaced by 491-5804, and 271-1716 (RH) by 491-5803. All four numbers share the same 279.4 mm bore and 1148 mm stroke — the difference between them is left-hand versus right-hand porting and mounting, and the revision level. If your parts book shows any of these numbers, we can supply the correct current-specification cylinder for your side.

On a production mining loader, the lift cylinders carry the full weight of the loaded bucket through every lift-and-load cycle, at high cycle rates across a full shift. The dominant failure modes are rod chrome wear and scoring from abrasive dust in the loading environment, and rod seal leakage once the chrome surface is compromised. Because a loader cannot work with one lift cylinder down, and because the two sides accumulate identical hours, lift cylinder condition is a direct driver of machine availability.

SEIGO manufactures the 271-1717 to full Caterpillar dimensional specification: a 42CrMo4 induction-hardened, hard-chrome-plated piston rod finished for abrasion and scoring resistance, an ST52 seamless honed steel barrel machined to the 279.4 mm bore, and a genuine NOK (Japan) or Parker (USA) seal kit rated for the 992K implement circuit. Each unit weighs approximately 1006 kg, is pressure tested at 1.5× rated working pressure before shipment from our Guangdong factory, and is backed by a 12-month or 2,000 operating-hour warranty. Standard lead time is approximately 30 days ex-works, with expedited production available for machine downtime.

Product Specifications

* OEM part numbers, brand names and model designations are used for identification and cross-reference purposes only. SEIGO Machinery is an independent aftermarket manufacturer and is not affiliated with Caterpillar Inc.

Cat 992K Lift Cylinder Cross-Reference (346-1000 Group)

The 992K uses paired left-hand and right-hand lift cylinders. Caterpillar has issued field-replacement numbers for both sides. All four numbers below share the same 279.4 mm bore and 1148 mm stroke; they differ by hand (LH/RH) and revision.

271-1717 and 491-5804 are the left-hand lift cylinder; 271-1716 and 491-5803 are the right-hand. If your parts book shows any of these four numbers, SEIGO supplies the correct current-specification cylinder for that side. Confirm your machine serial number before ordering.

Cat 992K Work Equipment Cylinder Reference

The 992K work equipment uses lift and tilt cylinders. Part 271-1717 is a lift cylinder; the tilt cylinders are different parts.

Lift and tilt cylinders are different parts with different bore and stroke and are not interchangeable. SEIGO supplies lift and tilt cylinders for the 992K — send us your machine serial number and the position you need to confirm the correct part.

Why This Cylinder, Specifically

• Correct hand and revision, verified. The 992K lift cylinder exists as left-hand (271-1717 / 491-5804) and right-hand (271-1716 / 491-5803). Ordering the wrong hand means the ports and mounting will not line up. We confirm the side and the current revision against your serial number before quoting.
• Manufactured to Cat dimensional spec. 279.4 mm (11 in) bore and 1148 mm (45.2 in) stroke, built to reproduce the original lift geometry and force curve exactly — no change to lift height or breakout.
• Abrasion-rated rod. On a production loader the dominant failure is rod chrome scoring from abrasive dust on the loading face. We specify 42CrMo4 with a hard chrome finish optimised for scoring resistance, because rod condition sets the seal service interval on this machine.
• Replace lift cylinders as a pair. Both lift cylinders share identical operating hours. If the LH cylinder has failed or is scored, the RH (271-1716 / 491-5803) is usually close behind. We supply matched LH/RH pairs on a single order to keep lift balanced and avoid a second shutdown.
• Rods, barrels and seal kits supplied separately. For workshops rebuilding in-house, we supply the piston rod, honed barrel, cylinder head, piston and seal kit as individual items — typically 40–60% of the cost of a complete cylinder, and far lower freight on a bare rod than on a 1000 kg assembly.
• Full traceability and testing. ISO 9001:2015 manufacturing, 100% pressure tested at 1.5× rated working pressure, shipped in an ISPM-15 fumigated export crate with material certificate and test record.

FAQ

Q1: Is 271-1717 the left-hand or right-hand lift cylinder?

A: 271-1717 is the left-hand (LH) boom lift cylinder for the Cat 992K, catalogued by Caterpillar as Cylinder Gp-Lift, LH. The right-hand cylinder is 271-1716. Both have a 279.4 mm bore and 1148 mm stroke, but the porting and mounting differ between sides, so the hand must be correct. Confirm which side you need before ordering.

Q2: What is the difference between 271-1717 and 491-5804?

A: They are the same left-hand lift cylinder position. Caterpillar issued 491-5804 as the field-replacement number for 271-1717 — both have the same 279.4 mm bore and 1148 mm stroke. If your parts book shows either number, SEIGO supplies the correct current-specification left-hand lift cylinder. The equivalent for the right-hand side is 271-1716, replaced by 491-5803.

Q3: Does 271-1717 fit all 992K machines?

A: The 992K was built under several serial prefixes — RM2, KK2, KK4, RM5, H4C, 880 and ZMX. 271-1717 applies across the 992K lift cylinder group, but because Caterpillar issues revisions and field replacements across build years, confirm against your full machine serial number before ordering. Send us the serial number and we will verify the correct current part for your machine.

Q4: Is the lift cylinder the same as the tilt cylinder on the 992K?

A: No. The lift cylinders (271-1717 LH, 271-1716 RH) have a 279.4 mm bore and 1148 mm stroke, in group 346-1000. The tilt cylinders (271-3572, 503-8431) have a 266.7 mm bore and a longer 2056 mm stroke, in group 361-0975. They are different parts and not interchangeable. SEIGO supplies both — specify lift or tilt when you enquire.

Q5: Can I buy the rod, barrel or seal kit separately instead of a complete cylinder?

A: Yes. SEIGO manufactures the piston rod, honed barrel, cylinder head, piston and seal kit as individual items and supplies them to hydraulic repair shops and rebuild facilities. For workshops with in-house honing and assembly capability, sub-component supply typically runs 40–60% of the cost of a complete replacement cylinder, and freight on a bare rod is far lower than on a complete 1000 kg assembly. Send us your machine serial number and the component you need for a quotation.

Q6: What is the lead time and how does it ship?

A: Standard production lead time is approximately 30 days ex-works Guangdong, China, with expedited production available for machine downtime. At approximately 1006 kg, each cylinder ships in an ISPM-15 fumigated wooden export crate, FOB Shenzhen, CIF or DDP. Sea freight is standard for planned replacements; air freight is available for urgent situations.

SEIGO Machinery is an independent aftermarket manufacturer. All OEM part numbers, brand names and machine model designations are used for identification and cross-reference purposes only. These aftermarket components are not manufactured by, endorsed by, or affiliated with Caterpillar Inc.