Description

Komatsu PC400-7, PC400LC-7, PC450-7, PC450LC-7 Technical Manual

I’ve been turning wrenches for 28 years, and if there’s one thing I’ve learned, it’s that skipping the test specs on a hydraulic pump will cost you a machine. This Komatsu PC400-7, PC400LC-7, PC450-7, PC450LC-7 Technical Manual is the exact document the factory uses to qualify remanufactured pumps. It’s not a vague aftermarket reprint—it’s 27 pages of numbers, diagrams, and procedures that will keep you from blowing a $10,000 main pump. The PDF opens with the pump identification and applications: HPV160+160 (190+190 cc/rev spec) for PC400/400LC-7 (serial #50001~) and PC450/450LC-7 (serial #20001~). Page 1 lists the stamping on the nameplate and part numbers. That alone can save a parts-ordering headache.

What’s Inside This 27-Page Testing Method Manual

Divided into five clear sections. The Table of Contents shows: Test Method (pages 3–11), Test Hydraulic Circuit Diagram (page 12), Performance Diagram and Standard Value Table (pages 13–24), Names of Sections and Related Dimension (pages 25–27), and a Schematic Diagram of Test Jig. Every page is packed with data, not fluff. For example, the Performance Diagram section gives you the flow vs. pressure curves you need to compare your bench results against. If your pump’s output doesn’t match the curve, something is wrong inside. The manual doesn’t tell you how to tear the pump apart—it tells you exactly how to verify the rebuild.

Why OEM Torque and Pressure Specs Matter on a Pump Test

Page 3 includes Table 1-1 – List of Test Specifications. You get piston pump capacity (190 cc/rev), EPC current dither (150mAp-p at 40Hz), max input shaft speed (1800 rpm conversion, 1500 rpm standard), max pressure (37.3 MPa {380 kg/cm²}), suction and drain pressures, and the EPC valve original pressure. Aftermarket manuals often round these numbers or use generic values. Try setting the EPC valve original pressure to 0.98 MPa instead of the correct 1.0 ± 0.5 range and see how fast the machine throws a code. This manual gives you the exact Komatsu specs. Use them.

This Is Not a Repair Manual – Know the Difference

If you’re looking for disassembly and assembly instructions, grab the Komatsu PC400/450-7 Shop Manual – Section: 30 Disassembly And Assembly. This 27-page technical manual is specifically for pump performance testing after a rebuild. It assumes you already have a rebuilt pump core. You’ll need a KHT75-3 hydraulic test stand (or equivalent). Without that bench, you can’t run the converted value tests. But if you have the stand, this manual is your pass/fail checklist. The scope is the remanufactured main pump HPV160+160 for PC400/450 series-7 machines. It also covers the Komatsu PC-7 Series Hydraulic Excavator Training Manual for additional background on the system.

Safety First: High-Pressure Hydraulic Testing

Page 3 opens with a warning I expect every tech to read twice: “Since high pressure is produced during this HST pump test, great care should be taken when selecting the equipment, device, test jigs and components. Also, great attention should be given to the pump installation condition, the hydraulic circuit configuration, and the universal joint connection.” That’s not boilerplate. A 380 kg/cm² burst will send shrapnel through a shop wall. I’ve seen it happen. This manual doesn’t let you forget the risks. It also specifies oil quality: Komatsu genuine engine oil E010-CD or equivalent, with discoloration managed to Class NAS10. Don’t substitute cheap oil.

Who Should Buy This Manual?

Home garage enthusiasts who own a PC400-7 or PC450-7 and plan to rebuild the main pump themselves? Yes, if you have access to a hydraulic test stand. Professional pump rebuilders? Absolutely—this is the factory verification procedure. Shop owners? Put this in your library for quality control. The manual is specific to the HPV160+160 pump, so if you’re working on a different pump, look elsewhere. But for these four models, it’s the final word on pass/fail criteria. The 27 pages are dense—no wasted space. You’ll find the exact values for converted and standard tests. For more context on how pumps interact with the rest of the drivetrain, read the Manual Transmission basics, but this manual is your pump bible.

Frequently Asked Questions

Does this manual cover the entire excavator or just the pump?

Just the main pump. The scope is the HPV160+160 (190+190 cc/rev) pump for PC400/450 series-7 machines.

Can I use this manual to rebuild a pump without a test stand?

No. The manual assumes you have a KHT75-3 test stand or equivalent. It’s for post-rebuild verification, not rebuild instructions.

What torque values are listed in this manual?

This is a testing method manual, so it doesn’t have bolt torque specs. Those are in the full shop manual, like the Komatsu PC400-7 PC450-7 2005 Workshop Manual – 782 Pages. However, it does list critical pressure settings you must set with an adjustable wrench—like the EPC valve original pressure (0.98 ± 0.05 MPa). Missing those by 0.1 MPa can cause the pump to shift incorrectly, leading to cavitation or seal failure. I’ve seen a $3,000 reman pump return because a tech set it to 1.1 MPa. The manual gives you the margin of error. Respect it. The Performance Diagram on pages 13–24 also gives you the expected flow at each pressure point so you can bench-test your pump against the factory curve. That’s an order of magnitude more valuable than a torque spec when you’re verifying a rebuild.

Why is this better than a generic hydraulic manual?

Generic manuals guess. This is the actual Komatsua testing procedure. Page 2 tells you it’s for quality verification of remanufactured pumps. That means each value was checked against production line standards. You get the same pass/fail criteria the factory uses. No room for error.

If you’re working on a Komatsu PC400-7, PC400LC-7, PC450-7, or PC450LC-7, stop relying on forum threads and aftermarket PDFs. This 27-page technical manual gives you the factory test method for the main pump. Pair it with the Manual Transmission basics if you need drivetrain theory, but for pump verification, this is the only source that won’t send a $10,000 pump back to you. Access the Factory Manual now and start testing with actual OEM data.