AP2D21-G2SP Hydraulic Pump | HANDOK HP2D21XR Main Pump 16.8CC 6.5CC

The hydraulic pump is the powerhouse of any excavator’s hydraulic system. For Korean-made HANDOK hydraulic systems, the AP2D21-G2SP hydraulic pump GP (also referenced as HP2D21XR) is a precision-engineered dual gear pump. It delivers reliable flow for main and pilot circuits. This OEM-grade pump is commonly found in compact excavators and construction machinery. A failing pump can cause slow operation, weak digging force, or complete hydraulic failure. Therefore, this direct replacement main pump restores factory-grade hydraulic performance. As a result, your equipment works efficiently on every job site.

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What Is the AP2D21-G2SP Hydraulic Pump?

The AP2D21-G2SP is a tandem dual-section gear pump. It combines two independent pumping sections in a single housing. The larger section provides high-flow main hydraulic power. The smaller section supplies lower-flow pilot pressure for control circuits. Consequently, this integrated design saves space and simplifies plumbing. The pump is part of HANDOK’s HP2D21XR series. It is built for Korean excavators and other heavy machinery.

Key Specifications (Typical for AP2D21-G2SP / HP2D21XR):

Pump Type: Dual-section gear pump (tandem)
Section 1 Displacement: 16.8 cm³/rev (main hydraulic section)
Section 2 Displacement: 6.5 cm³/rev (pilot / control section)
Shaft / Spline: 13T (13-tooth spline drive)
Mounting Flange: SAE A or SAE B (verify with OEM)
Rotation: Clockwise (R) – typical
Rated Pressure: 200–250 bar (Main) / 30–50 bar (Pilot)
Weight: Approximately 8–10 kg

Cross-Reference & Equivalent Numbers:
This pump may also be known by the following OEM or equivalent numbers:

HANDOK HP2D21XR
HP2D21-G2SP-16.8/6.5CC (13T)
AP2D21-G2SP

Why Choose This HANDOK Main Pump?

Tandem dual-section design. The 16.8 cc section powers main functions (boom, arm, bucket, swing, travel). The 6.5 cc section supplies pilot pressure for control valves. Hence, no separate pilot pump is needed.
OEM-grade fitment. HANDOK pumps are original equipment on many Korean compact excavators. Therefore, this pump matches factory mounting dimensions, spline drive, and port locations.
Durable gear construction. Hardened steel gears resist wear and extend service life. The cast iron housing withstands high pressure and shock loads. This ensures reliable operation in harsh conditions.

Compatibility and Applications

The AP2D21-G2SP / HP2D21XR main pump is widely used in compact and medium-sized construction machinery. Below are common applications and compatible machine models:

Excavators (Korean & Global Brands):

Daewoo / Doosan: DH35, DH40, DH55, SOLAR 55, SOLAR 60
Hyundai: R55-7, R55-9, R60-7, R60-9, R60W-9, R80-7, R80-9
Kobelco: SK55, SK60, SK70 (some variants)
Komatsu: PC35, PC40, PC45, PC50, PC55, PC60
Hitachi: EX35, EX40, EX45, EX50, EX55, EX60
Kubota: KX101, KX121, KX161, U35, U45
Volvo: EC35, EC40, EC45, EC55, EC60
Takeuchi: TB135, TB145, TB153, TB175 (some variants)

Wheel Loaders (Compact & Mini):

Komatsu: WA30, WA40, WA50, WA80, WA100, WA120
Kawasaki: Compact wheel loader series
TCM / Yanmar: Compact wheel loaders

Skid Steers & Track Loaders:

Bobcat: Some compact models with Korean-made hydraulic systems
Case: Some compact models
Gehl / Mustang: Some compact models

Other Construction Equipment:

Compactors: Mini vibratory rollers
Small cranes and material handlers

How This Pump Fits the Hydraulic System

The 16.8 cc section is the main pump. It draws oil from the tank and sends high-pressure flow to the main control valve. This flow powers all major hydraulic functions:

Boom up / down
Arm (stick) in / out
Bucket curl / dump
Swing left / right
Track travel forward / reverse

The 6.5 cc section is the pilot pump. It supplies lower pressure oil to the pilot control valve. The pilot pressure (30–50 bar) moves the spools inside the main control valve. This allows precise, proportional machine control. Because both sections are in one housing, installation is simpler. Mounting and alignment are also more reliable.

Signs Your AP2D21-G2SP Pump Needs Replacement

Watch for these common failure indicators:

Slow or weak hydraulic functions. The boom, arm, or bucket moves slower than normal. Digging force is noticeably reduced. This is often the first sign of pump wear. Loss of pressure or flow may be the cause.
Unusual noises from the pump area. Whining, knocking, or grinding sounds indicate internal wear. Cavitation or gear damage may also occur.
Poor machine tracking. The excavator pulls to one side. Uneven flow between the two main pump sections (if dual-section) is a likely cause.
Overheating hydraulic oil. Excessive internal leakage generates heat. The pump may be worn or damaged.
Pilot function issues (slow response, jerky control). The smaller 6.5 cc section may be worn. Pilot pressure may be too low.
External hydraulic oil leaks. Seals may be worn or the housing may be cracked.
Increased fuel consumption for same workload. The engine works harder to compensate for pump inefficiency.

Installation Recommendations

Follow these steps for a successful replacement. First, depressurize the hydraulic system and disconnect the battery. Second, drain the hydraulic oil and remove the old pump.

Clean the pump mounting area thoroughly. Then, inspect the drive coupling and spline shaft for wear. Replace them if damaged. Install new O-ring seals on all ports. Mount the new AP2D21-G2SP / HP2D21XR pump. Tighten mounting bolts to OEM specifications (typically 40–60 Nm for M10 bolts).

Connect all hydraulic lines to their correct ports. Refill with clean hydraulic oil (ISO VG 32, 46, or as specified). Finally, start the engine at low idle. Cycle all hydraulic functions to bleed air from the system. Check for leaks and verify pump operation.

Conclusion

The AP2D21-G2SP hydraulic pump GP for Korean HANDOK HP2D21XR excavator is a high-quality dual-section main pump. It delivers 16.8 cc for main hydraulic power and 6.5 cc for pilot control. Whether you are repairing a Doosan DH55, a Hyundai R60-7, a Komatsu PC40, a Kubota KX121, or a Hitachi EX35, this OEM-grade pump restores factory hydraulic performance.

Order your AP2D21-G2SP / HANDOK HP2D21XR main pump today. Keep your compact excavator or wheel loader digging strong.