Komatsu PC30MR-2 Troubleshooting: What to Do When Your Hydraulic Pump (708-3S-04570) Fails?

Struggling with slow movements or power loss on your Komatsu PC27MR or PC35MR-2? This guide helps you diagnose the 708-3S-04570 hydraulic pump, explains part number supersessions, and provides pro tips for installation to prevent premature failure.

If your Komatsu mini excavator starts to feel sluggish after a few hours of work, you are likely facing a common hydraulic issue. In the PC27MR-2, PC30MR-2, and PC35MR-2 series, the 708-3S-04570 hydraulic pump acts as the heart of the system. Once it wears down, your entire job site efficiency drops.

In this guide, we’ll break down how to identify a failing pump and what you need to know before replacing it.

1. Common Symptoms of 708-3S-04570 Failure

Don't wait for the pump to snap. Watch for these early warning signs:

• Power Loss When Hot: The machine works fine for the first 30 minutes, but cycle times slow down significantly as the hydraulic oil temperature rises.

• Tracking Issues: One track moves slower than the other, causing the excavator to "drift" to one side while traveling.

• Abnormal Noise: A high-pitched whining or grinding sound coming from the pump area, especially under heavy load.

2. Part Number Update: 708-3S-04570 vs. 708-3S-04571

When searching for a replacement, you may encounter two different part numbers. Here is the quick lookup:

• 708-3S-04570: The original part number found on many older PC30MR-2 units.

• 708-3S-04571: The official Komatsu supersession.

  Note: These two are 100% interchangeable. The "04571" is an improved version designed for better durability. If you order one and receive the other, it will still be a perfect bolt-on fit.

3. Compatible Engine & Machine Models

This pump is specifically engineered for Komatsu mini excavators powered by Yanmar 3D82, 3D84, or 3D88 engines.

4. Pro Installation Tips 

To ensure your new pump lasts for years, follow these two critical steps:

• Case Drain Priming: Never start the engine with a dry pump. Fill the pump case with clean hydraulic oil through the top drain port before connecting the hoses.

• System Flush: If your old pump suffered from internal metal failure, there will be metal shavings in the tank. Failure to flush the system and replace the suction filter will destroy your new pump within hours.

• https://beespareparts.com › products › 708-3s-04570-gear-pump-hydraulic-pump-for-komatsu-pc55mr-3-pc50mr-2-pc40mr-2