173-8612 CAT 988G / 988H Wheel Loader Lift Cylinder (RH) Aftermarket Replacement

Product Overview

SEIGO’s aftermarket lift cylinder, part number 173-8612, is a direct drop-in replacement for the right-hand (RH) lift cylinder position on Caterpillar 988G and 988H large wheel loaders — covering serial number prefixes BNH and 2TW (988G) and BXY and A7A (988H). Confirmed in the Caterpillar 988G Hydraulic System Technical Manual (RENR2172-02, BNH1-Up / 2TW1-Up) as CYLINDER GP-LIFT, RH, this component works in tandem with the left-hand lift cylinder 173-8613 to raise and lower the entire boom and bucket assembly through the 988’s Z-bar linkage system.

On the CAT 988G and 988H — machines in the 49,000–50,000 kg operating weight class, powered by the CAT 3456 EUI (475 HP) and CAT C18 ACERT (507 HP) engines respectively — the lift cylinders endure the full weight of the boom, Z-bar linkage, tilt cylinder, and loaded bucket on every raise cycle. In truck-loading operations, a 988 completes hundreds of full lift-lower sequences per shift, each cycle putting the lift cylinders through maximum extension force at the start of the raise (when the mechanical advantage is at its lowest and bucket is fully loaded) and maximum retraction speed during the lower cycle. The Z-bar linkage geometry means that the lift cylinders also absorb lateral loads from bucket crowd-in at the pile — loading conditions that accelerate rod chrome wear and piston seal fatigue over time.

With a confirmed bore of 220 mm and stroke of 911 mm, the 173-8612 is a large, high-force cylinder operating at the full implement system relief pressure of approximately 4,500 PSI. SEIGO manufactures the 173-8612 with a 42CrMo4 induction-hardened, hard-chrome-plated piston rod to HRC 58–62, providing resistance to chrome scoring from grit and rock debris in the Z-bar linkage pivot zone. The cylinder barrel uses ST52 seamless honed steel with bore finish maintained to OEM tolerance. A genuine NOK (Japan) or Parker (USA) seal kit is fitted throughout. Every unit is pressure-tested at 1.5× rated working pressure before shipment from SEIGO’s Guangdong, China factory, and is backed by a 12-month or 2,000 operating-hour warranty, whichever comes first. Standard lead time is 2–3 weeks, with a 5–7 day Rapid Production Track for mine-site and quarry emergency orders.

Technical Specifications Table

Machine Fitment & Serial Number Ranges

• Caterpillar 988G (SN prefix: BNH, produced 2001–2005) — fits 173-8612 RH; engine: CAT 3456 EUI, 354 kW / 475 HP
• Caterpillar 988G (SN prefix: 2TW) — fits 173-8612 RH; confirmed in RENR2172-02 (BNH1-Up / 2TW1-Up)
• Caterpillar 988H (SN prefix: BXY, produced 2005–2013) — fits 173-8612 RH; engine: CAT C18 ACERT, 373 kW / 507 HP
• Caterpillar 988H (SN prefix: A7A, produced 2012–2015) — fits 173-8612 RH

Note: The CAT 988K (SN prefix TWX / LWX, produced 2013–2018) uses a revised lift cylinder specification. If you are operating a 988K, please provide your full serial number to SEIGO’s engineering team for confirmation before ordering.

Key Features & Quality Points

• OEM-confirmed specification: 220 mm bore, 911 mm stroke — sourced directly from Caterpillar Hydraulic System Technical Manual RENR2172-02
• RH position confirmed; paired with 173-8613 (LH) — one of each required per machine
• Covers full 988G production run (BNH, 2TW) and full 988H production run (BXY, A7A) under a single part number
• 42CrMo4 induction-hardened rod to HRC 58–62 — resists chrome scoring from rock debris and grit in the Z-bar linkage pivot zone
• ST52 seamless honed steel barrel, bore finished to OEM tolerance for consistent seal life across the full 911 mm stroke
• NOK (Japan) / Parker (USA) premium seal kit — zero-leakage performance at 988-class implement system pressure
• 100% pressure tested at 1.5× rated working pressure before shipment
• ISO 9001:2015 certified manufacturing process
• Drop-in fitment — no machine modification required
• 12-month / 2,000-hour warranty, whichever comes first
• Export-grade fumigated wooden crate packaging
• FOB Shenzhen / CIF / DDP shipping terms available

FAQ

Q1: Is SEIGO 173-8612 dimensionally identical to the Caterpillar OEM part? A: Yes. Our 173-8612 is manufactured to match all OEM specifications including the 220 mm bore, 911 mm stroke, rod diameter, mounting pin-eye dimensions, port locations, and thread specifications as documented in Caterpillar Technical Manual RENR2172-02 for the 988G (BNH1-Up / 2TW1-Up). It is a true drop-in replacement requiring no modification to the machine.

Q2: What is the difference between 173-8612 and 173-8613? A: Parts 173-8612 and 173-8613 are the right-hand (RH) and left-hand (LH) lift cylinders respectively on the CAT 988G/H — one for each side of the Z-bar linkage boom. They share the same bore (220 mm) and stroke (911 mm) but are mirror-image assemblies with port locations and pin-eye orientations suited to their respective sides. Each machine requires one 173-8612 (RH) and one 173-8613 (LH). SEIGO supplies both, individually or as a matched pair on a single purchase order.

Q3: Does 173-8612 fit both the 988G and 988H? A: Yes. Part 173-8612 covers the full production run of the 988G (serial prefixes BNH and 2TW, 2001–2005) and the full production run of the 988H (serial prefixes BXY and A7A, 2005–2015). If you operate a 988K (serial prefix TWX or LWX, 2013–2018), please confirm fitment with our engineering team before ordering, as the 988K introduced specification updates to the lift cylinder.

Q4: What is the lead time for 173-8612? A: Standard production lead time is 2–3 weeks ex-works Guangdong, China. For quarry or mine-site emergency orders, our Rapid Production Track delivers in 5–7 working days subject to materials availability. Air freight to major international airports adds approximately 3–5 days transit time.

Q5: What are the common failure signs on the 988G/H lift cylinder? A: The most frequent indicators of lift cylinder failure are: visible hydraulic oil leakage at the rod seal — typically appearing as oil streaking down the chrome rod surface; boom drift under load — the boom slowly lowers when the implement lever is in the hold position with the engine running; loss of full lift height or reduced lift force during a loaded cycle; and visible chrome scoring or pitting on the rod surface during the pre-shift inspection. Rod seal leakage is the most common initiator, usually caused by chrome surface wear from grit and rock particles accumulating in the Z-bar linkage area. Left unaddressed, contaminated oil progressively damages the implement pump and main control valve.

Q6: Should both lift cylinders (LH and RH) be replaced at the same time? A: If one cylinder has failed, we recommend a close inspection of the opposite side at the same time. Both cylinders work identical loads and duty cycles — at similar operating hours, the second cylinder is likely approaching the same wear threshold. Replacing both in a single planned shutdown eliminates the risk of a second unplanned stoppage and maintains balanced boom geometry. SEIGO supplies matched 173-8612 (RH) and 173-8613 (LH) pairs on a single purchase order.

Q7: What is the relationship between the lift cylinder (173-8612) and the tilt cylinder (231-1955) on the 988G/H? A: These are two separate and functionally distinct cylinders. Part 173-8612 is the right-hand lift cylinder — it raises and lowers the boom assembly. Part 231-1955 is the bucket tilt cylinder — it controls the rack-back and dump motion of the bucket. Both are critical hydraulic actuators on the 988G/H front linkage, but they are not interchangeable and should be ordered separately. SEIGO manufactures and stocks both cylinders for the 988G/H platform.

Q8: Do you supply to quarry and mining operations globally? A: Yes. We regularly supply CAT 988-series lift and tilt cylinders to operations across Australia (iron ore, coal, quarrying), Chile (copper, aggregate), South Africa (platinum, iron ore), Indonesia (coal, nickel), Mongolia (via China rail), and West Africa. We support FOB Shenzhen, CIF, and DDP Incoterms.