The hydraulic system is the source of power in excavators, wheel loaders and cranes, and any failure in it stops the machine completely. Among the most requested heavy equipment hydraulic parts are the main pump, swing motor, travel motor, main control valve, hydraulic cylinders and seal kits.
China is a major source of these parts, whether genuine, new aftermarket, remanufactured or used, for excavators such as Hitachi, Komatsu, Caterpillar, Volvo, Doosan, Hyundai, Kobelco and others. But buying correctly depends on matching the part number and model precisely, not just the machine name.
The main hydraulic parts on an excavator
1. Main pump
Turns engine power into oil pressure and flow that drive every excavator movement: boom, arm, bucket, swing and travel.
On most medium and large excavators the main pump is a variable-displacement axial piston pump, often a tandem unit (two pumps in one housing), with a small pilot pump for the control circuit.
2. Swing motor
Rotates the excavator's upper structure, working with a swing reduction gearbox.
3. Travel motor and final drive
Drives the tracks, combining a hydraulic motor with a reduction gearbox.
4. Main control valve
Distributes oil from the pump to the different functions according to the operator's commands.
5. Hydraulic cylinders
Boom, arm and bucket cylinders, which regularly need seal kits and sometimes a new rod or bushing.
6. Other parts
Such as solenoid valves, joysticks, hydraulic hoses, filters and the pump regulator.
The main pump on a Hitachi excavator: a practical example
Hitachi ZX-series excavators are among the most widespread, so demand for their main pumps is high.
Some Hitachi models use HPV-series pumps, such as the HPV102 on a number of ZX200 models, while excavators from other brands often use Kawasaki pumps from ranges such as K3V and K5V, which are among the most common pumps on excavators.
But the same model can come with different pumps depending on its generation (such as -3 or -5), year and market. So "a pump for a ZX200" isn't enough. You need to identify the part number precisely, as explained below.
Types of hydraulic parts available from China
Genuine parts
Parts carrying the excavator manufacturer's brand and original part number. The most expensive, with the most confidence in fit.
OEM component-maker parts
Many excavator brands don't make their own pumps. They buy them from specialist makers, so a pump made by a company such as Kawasaki may be fitted to excavators of several brands.
Buying the pump from the component maker under its own part number can cost less than buying it under the excavator brand's number, even though it is essentially the same part. But you must confirm the number, regulator and settings match.
New aftermarket parts
New parts made by Chinese factories to match the original in dimensions and performance. Prices are clearly lower, and quality varies a lot between factories.
Remanufactured parts
Used genuine parts that have been rebuilt: stripped, inspected, fitted with new internal wear parts such as pistons, cylinder block and valve plate, then tested on a test bench.
Used parts
Genuine parts removed from other machines and sold as is. The cheapest option but the highest risk, and they need inspection and testing.
How to match the part number precisely
Before ordering any pump or motor, prepare:
- The full machine model and generation, such as ZX200-3, not just ZX200.
- The machine's serial number from its data plate.
- The part's own nameplate: a clear photo of the plate on the pump, showing the pump model and number.
- The part number from the parts catalogue, if available.
- Photos of the part from several angles: regulator, solenoid, ports, shaft (the number of spline teeth) and mounting.
- Direction of rotation and flange type.
Why all this detail? Two pumps with the same trade name can differ in regulator, number of shaft splines, port positions or pressure settings, and any one of these differences can stop it fitting or cause poor performance.
Signs of a failing main pump
- General loss of power and slow movements.
- High hydraulic oil temperature.
- Abnormal noises from the pump, such as whining or knocking.
- Metal particles in the filters or the oil.
- Weakness when running more than one function at once.
- Low pressure when measured.
Note: some of these symptoms can be caused by the regulator, relief valve or control valve rather than the pump itself. It is best to measure pressure and flow before buying a complete pump.
A critical point: clean the system before fitting the new part
If the old pump failed, metal particles have probably spread through the whole system. Fitting a new pump into a contaminated system can destroy it within a short time.
Before installation:
- Clean the hydraulic tank.
- Replace all the hydraulic oil.
- Replace every filter.
- Check the hoses and oil cooler and remove any debris.
- Fill the pump housing with oil before first start-up and bleed the air according to the maker's instructions.
Warranties usually require proof that the oil and filters were changed at installation.
How to check pump quality before shipping
- A test bench report: showing pressure and flow at different speeds, with a video of the test if possible.
- Photos of the nameplate and serial number of the exact part being shipped.
- For remanufactured parts: a list of the internal parts that were replaced.
- For used parts: photos of the internal parts if possible, or a performance test.
- Packaging: ports sealed with caps to keep out dust and moisture.
Warranty
The warranty period depends on the type of part (genuine, new aftermarket, remanufactured or used) and its condition, and we state it in writing in the quote for each part.
Warranty terms usually require correct installation by a qualified technician, cleaning the system and changing the oil and filters at installation, and using oil of the correct specification. Failures caused by contaminated oil or incorrect installation are usually not covered.
Shipping hydraulic parts from China
- Main pumps and motors are heavy and ship in securely fixed wooden crates.
- Air or express freight suits urgent parts when the machine is down, because the cost of downtime can be greater than the difference in freight.
- LCL sea freight suits non-urgent parts and stock orders.
- Parts from several suppliers can be consolidated into one shipment to cut costs.
Common mistakes when buying hydraulic parts
- Ordering the pump by excavator name alone, without the part number and nameplate.
- Ignoring differences in the regulator or number of shaft splines.
- Fitting a new pump into a contaminated system without cleaning it and changing the oil and filters.
- Buying a complete pump when the problem is the regulator or relief valve.
- Buying a used part without a test report.
- Shipping an urgent part by sea while the machine is down.
How we work with you
China Aurora (Guangzhou Aurora Trading Co., Ltd.) is a Guangzhou-based company that sources heavy equipment spare parts and used machinery, inspects quality and ships from China. This is how we help with hydraulic parts:
- You send us the machine model, serial number, and a photo of the part's nameplate and number.
- We match the number and send you options: genuine, OEM component-maker, new aftermarket, remanufactured or used, with the price and warranty for each.
- We check the supplier and ask for the test report and photos of the actual part before you pay.
- We inspect the part and its packaging before shipping.
- We arrange air freight for urgent parts or LCL sea freight for stock orders to your country.
Send us the machine and part details on WhatsApp at +86 185 2028 8213 for a quote.
FAQs about heavy equipment hydraulic parts
Is the main pump the same on every Hitachi ZX200?
No. The pump can differ by generation, year and market, so identify it by part number and nameplate.
What is the difference between a genuine part and an OEM part?
A genuine part carries the excavator brand's part number. An OEM part comes from the component maker itself under its own number, and can be essentially the same part for less, as long as the number and settings match.
Are remanufactured parts reliable?
They can be a good option if properly remanufactured and tested on a test bench, with a list of the parts replaced.
How long does an urgent pump take to ship?
It depends on the destination and availability. Air or express freight is much faster than sea, and is usually the right choice when the machine is down.
Why does a new pump fail soon after installation?
The most common cause is a system contaminated with debris from the old pump, air in the system, or not filling the pump with oil before first start-up.
Conclusion
Buying heavy equipment hydraulic parts, especially the main pump for Hitachi and other excavators, starts with matching the part number and nameplate precisely, then choosing the type that fits your budget, checking the test report and cleaning the system before installation.
If you want us to match, inspect and ship the part for you, send your machine details on WhatsApp at +86 185 2028 8213.