Comparison Table of Common Faults and Corresponding Replacement Parts for Hydraulic Main Pump

Comparison Table of Common Faults and Corresponding Replacement Parts for Hydraulic Main Pump

I. General Fault Diagnosis + Repair and Part Replacement

II. Precision Fault-Specific Parts Exclusive to Each Brand's Main Pump

1. Kawasaki K3V/K5V/K7V series

1) The K3V63/112/140/180 models have insufficient power.

Replacement: Plunger + Cylinder Block + Flow Plate + Major Overhaul Kit

2) Unusual noise from the Kawasaki pump

Replacement: spindle bearing, swing seat, swash plate

3) The Kawasaki lift mechanism exhibits slow fault response.

Replacement: Flow booster assembly, servo valve core

2. Komatsu HPV Series (entire PC range)

1) HPV95/160 weak warm-up capacity

Essential replacement parts: 708-2L distributor plate + plunger + original factory repair kit

2) Komatsu pump oil leakage

Replacement: Original factory frame oil seal and end cover gasket

3) Stalling due to vehicle congestion

Replacement: Komatsu-specific lifting device, flow pull rod

3. Hitachi HPV Series (ZAX/EX)

1) Internal leakage in the Hitachi 200 main pump

Replacement: Hitachi 118-plunger cylinder block + distributor plate

2) Stuttering motion

Replacement: Nine-hole return disk, steel balls

4. Rexroth A10VSO/A4VG/A11VLO

1) Pump truck A4VG has weak driving power.

Replacement: closed-loop pump plunger, distributor plate, sealing pack

2) Insufficient pressure for small and medium-sized excavators A10VSO

Replacement: A10VSO complete oil seal kit + plunger

5. KYB small excavator main pump (PSVD2-27/42)

1) The 55/60/75 small excavator operates at a slow speed throughout its operation.

Replacement: KYB plunger + distributor plate + small pump repair kit

2) Small excavating pumps tend to overheat easily.

Replacement: Heat dissipation pilot pump + oil inlet filter

III. Priority Replacement Sequence for Hydraulic Pump Maintenance (Cost-Saving Repair Procedure)

1. Minor oil leakage → Replace only the oil seal and use the basic repair kit

2. Slow movement with low pressure → Replace the distributor plate and return plate

3. Both hot and cold engines fail → Directly replace the piston and cylinder block

4. Abnormal noise + severe heating → Full overhaul: overhaul kit + plunger + distributor plate + bearing +斜盘 (clutch disc)

5. Abnormal electrically controlled flow → Replace the lift mechanism/servo valve

IV. Maintenance and Repair Taboos (Practical Tips)

1. It is strictly prohibited to fill the hydraulic pump with oil without replacing its components; prolonged use will lead to more severe wear.

2. The thickened wear-resistant distributor plate must be replaced under high-temperature operating conditions.

3. Heavy-duty mining machinery models directly utilize reinforced pistons.

4. After repair, it is mandatory to replace with brand-new genuine hydraulic oil and all vehicle filters.

5. The use of repair kits from different brands is prohibited, as this may lead to pressure release and oil leakage.

Failure phenomenon, failure cause, primary replacement part, backup part

The entire machine lacks power and moves slowly; there is internal leakage in the piston. The issues involve the piston assembly, cylinder block, distribution plate, and return plate.

The cold engine is powerful but the hot engine lacks power; the distributor plate is worn out. Use a high-wear-resistant distributor plate and a thrust plate.

Oil leakage from the pump body, aging of oil seals, main shaft frame oil seals, and end cover gaskets

The hydraulic pump produces significant noise; the rocking seat is worn out; there are issues with the swashplate assembly and the servo piston.

The pressure fluctuates unpredictably; the thrust stop plate is uneven; the thrust stop wear-resistant plate requires adjustment using a gasket.

Vehicle stall due to gear drop and engine shutdown; flow mechanism damaged; hoist assembly; flow pull rod

The pilot action is sluggish; the pilot pump is worn out; it is a pilot gear pump with a pilot oil seal.

The pump body has low heating efficiency; the ball joint return disc is worn out, and the steel balls in the return disc require major overhauling.

The running speed varies unevenly; the servo valve core is stuck; servo valve assembly; adjustment spring

The oil temperature is too high; the bearing clearance is excessive; this applies to the main shaft bearing and the needle roller copper bushing.