Komatsu PC40MR-2 / PC50MR-2 Hydraulic Pump: How to Match the Right Part Number (708-3S-00462 & Alternatives, 2026)

Quick Answer

Key Takeaways

• PC40MR-2 and PC50MR-2 share the same pump family — the reference number is 708-3S-00462.
• The same physical pump can be sold under 5–6 different part numbers; the number alone does not always identify the pump.
• Confirm by machine model + serial number + the plate on the old pump — not by the part number you happen to find online.
• It is a load-sensing variable pump: flow is delivered on demand, which means responsive control and lower energy consumption on a compact machine.
• Net weight is about 33.93 kg — light enough for one person to handle with basic lifting gear.
• Original mounting dimensions and ports allow direct replacement of the original pump body.

Table of Contents

• 1. The "One Pump, Six Numbers" Problem
• 2. The Pump Behind the PC40MR-2 & PC50MR-2
• 3. How Komatsu Part Numbers Are Structured
• 4. Part Number Cross-Reference
• 5. How to Confirm the Right Pump for Your Machine
• 6. Load-Sensing Variable Pump on a Mini Excavator
• 7. Why Compact Excavator Pumps Fail
• 8. Rebuild vs Replace on a Mini Excavator
• 9. What to Send for an Accurate Quote
• 10. FAQ
• 11. Match Your PC50MR-2 Pump Today

1. The "One Pump, Six Numbers" Problem

If you own a Komatsu PC40MR-2 or PC50MR-2 mini excavator and the main pump has failed, you already know the frustration: search online and you will find the same pump listed under half a dozen different part numbers. Which one is yours? Do they actually differ? Will the wrong number damage the machine?

The short answer is that these compact machines share a pump family, and Komatsu has used several reference numbers across production batches and applications. That is why a number alone is not enough. This guide shows you how to move from a part number to a confirmed match — the way a parts professional would. If you are comparing Komatsu excavator parts for a mini machine, start here.

2. The Pump Behind the PC40MR-2 & PC50MR-2

Always confirm against the identification plate on your original pump and your machine serial number — numbers can vary with production batch and market.

3. How Komatsu Part Numbers Are Structured

Komatsu part numbers follow a grouped format, written as blocks separated by hyphens — for example 708 - 3S - 00462. The leading block groups the component family, and the trailing block is the individual item number within that family. A widely used reference for the same component in different applications can therefore share the leading block but differ in the trailing digits.

The practical lesson: a part number is an identifier, not a specification. Two numbers can point to interchangeable pumps, and one number can be superseded by another over time. Never buy on the number alone — match it to the machine.

4. Part Number Cross-Reference

For the PC40MR-2 / PC50MR-2 pump family, the following reference numbers are the ones most commonly associated with this compact pump:

Because several numbers can apply to the same machine build, the safe rule is: send your machine model, serial number and the plate number from the failed pump together, and let the supplier confirm. A verified supplier will match your pump to the correct current number rather than guess.

5. How to Confirm the Right Pump for Your Machine

• 1. Read the machine plate. Record the exact model (PC40MR-2 or PC50MR-2) and serial number.
• 2. Find the pump identification plate. The number stamped on the pump body is the most reliable starting point.
• 3. Photograph the pump from three angles — side, mounting flange, and the ID plate — so a supplier can see the mounting face and ports.
• 4. Note the control type. Confirm the regulator / control setup matches your machine's behaviour.
• 5. Send all of it together so the match is confirmed in one round, not three.

6. Load-Sensing Variable Pump on a Mini Excavator

On a compact machine, hydraulic efficiency matters more than raw power — the engine is small and the duty cycle is stop-start. The PC40MR-2 / PC50MR-2 pump uses a load-sensing variable structure: it senses what the work function actually needs and delivers flow on demand, rather than pumping a fixed flow all the time.

The result is responsive control, less wasted energy (and less heat) during light-duty work, and smoother operation for the operator. A precision plunger and valve plate assembly, built to be wear- and heat-resistant, keeps pressure stable through continuous work and extends overall machine service life.

7. Why Compact Excavator Pumps Fail

Mini excavators fail differently from large machines. The pump is small, the engine bay is tight, and the machine often runs a high proportion of short, repetitive cycles. The most common causes:

The fix is the same as on a large machine — clean oil, correct filters, and oil temperature kept under control — but on a compact machine those disciplines pay back even faster, because the oil volume is small. Downstream damage is also a risk: debris from a failing pump can reach the control valve assemblies, turning one repair into two.

8. Rebuild vs Replace on a Mini Excavator

At roughly 33.93 kg, this pump is physically easy to handle — but that does not make a rebuild the right choice. A rebuild only replaces the wear that is visible; housing and shaft wear often surface later as a second failure. For a machine that earns its keep, a verified complete assembly — matched, tested as a unit and warrantied — is usually the lower total-cost option once downtime is counted. Use a rebuild only when the housing and shaft are confirmed sound and a clean workshop is available.

9. What to Send for an Accurate Quote

Send these five items in one message and you will get a confirmed match and price in a single round:

• 1. Machine model (PC40MR-2 / PC50MR-2) and serial number.
• 2. The part number from the pump's ID plate (e.g., 708-3S-00462).
• 3. Photos of the pump — side view, mounting flange and ID plate.
• 4. The failure symptom (weak digging, high temperature, noise, metal in the filter).
• 5. Shipping requirement — sea or air, destination, and required lead time.

You can browse the full parts range at excavator hydraulic parts and learn more about RITO HYDRAULIC.

10. FAQ

Q1: Do the PC40MR-2 and PC50MR-2 use the same hydraulic pump?

They share the same compact pump family, referenced as 708-3S-00462 and listed with several companion numbers. Confirm against your machine serial number and the pump ID plate before ordering.

Q2: Why does the same pump have several part numbers?

Komatsu part numbers can change with production batch, application and supersession. The same physical component can therefore appear under more than one number, which is why the number alone is not a specification.

Q3: Which part number fits my PC50MR-2?

Start with the number on your pump's ID plate and match it with your machine serial number. The common reference numbers for this family are 708-3S-00462, 708-3S-00461, 708-3S-00522, 708-3S-00870 and 708-3S-00872.

Q4: What is the weight of the pump?

Approximately 33.93 kg — a compact unit that one person can move with basic lifting gear.

Q5: What type of pump is it?

It is a load-sensing variable displacement pump. It delivers flow on demand, which gives responsive control and lower energy consumption on a compact machine.

Q6: Can I install it as a direct replacement?

Yes. The pump uses original mounting dimensions and port specifications, so it directly replaces the original pump body without adapters.

Q7: How do I know my mini excavator pump is failing?

Watch for weak digging, slow cycle times, rising oil temperature, whining or knocking, and metal particles in the return filter. Metal debris is the most urgent warning.

Q8: Should I flush the system when replacing the pump?

Yes. Flush the system and replace the return filter and suction strainer at the same time — old debris from the failed pump will damage the new one.

Q9: Why does my mini excavator pump run hot?

Common causes are a clogged oil cooler, low oil level, wrong oil grade, or internal pump leakage converting flow to heat. Investigate any sustained temperature above 80°C.

Q10: How can I be sure the pump is good before it ships?

Ask for the per-unit test report. A verified supplier bench-tests the pump for flow, pressure and leakage and provides the data before shipment.

11. Match Your PC50MR-2 Pump Today

Send us your machine model, serial number and the part number from your pump plate — plus a couple of photos — and our team will confirm the correct number, provide a test-report sample and quote lead time the same day. RITO HYDRAULIC supplies complete, individually tested pumps, swing motors, travel motors and control valves for Komatsu, Caterpillar, Hitachi, Hyundai, Kobelco, Doosan and Kawasaki / Rexroth-series machines, with export packing and a 6–12 month warranty.

Contact our team for a same-day quotation.