Description

Komatsu D85C-21 1995 Workshop Manual

You do not need a dealer’s diagnosis to drop a transmission or chase a brake drag. What you need is the Komatsu D85C-21 1995 Workshop Manual – the same 523-page binder that Komatsu issued to its own techs. Without the factory specs, you are guessing on clearances, torque values, and hydraulic pressures. That costs you a rebuild job or a blown seal. I have seen it happen.

Transmission and Brake Diagnostics: Factory Procedures

Section 10 (Structure and Function) breaks down the Torqflow Transmission, the Transmission Control Valve, the steering clutch, and the steering brake. You get hydraulic piping diagrams and circuit diagrams for the entire power train. When the machine creeps in neutral or won’t steer, you trace the problem through the valve stacks and the lubrication circuit – not a generic flow chart from a third-party site. The factory diagram on page 10-1 shows every line and orifice.

Torque Specs You Can Trust

Section 20 (Testing and Adjusting) includes the Standard Value Table for Engine Related Parts and for chassis components. That is where you find the exact torque for head bolts, main bearing caps, and transmission case bolts. Aftermarket manuals often round up or omit the step-angle torques. This one gives you the Komatsu numbers. Use the wrong torque on a bevel gear shaft and you are buying a new carrier. I have torqued enough bolts to know the factory spec is the only safe bet.

Does It Cover the Engine Valve Train?

Yes. Section 20 includes a dedicated procedure for Adjusting Valve Clearance. It also covers fuel injection timing, measuring compression pressure, and blow-by pressure. If you need to pull the valve cover on the S6D125-2 engine, this manual walks through the clearance adjustment with feeler gauge specs and the correct sequence. No shortcuts, no “close enough”.

3 Systems the Manual Walks You Through

First, the Power Train – from torque converter stall test to final drive disassembly. Second, the Steering and Brake Control – includes the steering main relief valve, the brake pedal linkage adjustment, and the entire brake control valve body. Third, the Counterweight System – hydraulic circuit diagrams, control valve and piping. Each system has its own troubleshooting chart in section 20, with fault codes like H-2 (machine does not move) or H-6 (excessive shock when shifting). You follow the sequence of events list until you find the failed component.

Why This OEM Print Beats Any Aftermarket Copy

This is a 1995 Komatsu publication, printed in Japan, not a scanned reprint from a manual aggregator. The PDF you access from AutoRepairManuals is the original factory file – 523 pages, no missing pages, no blurred diagrams. The electrical circuit diagram and actual wiring diagram are crisp. Aftermarket copies frequently have missing torque data or rearranged sections to fit a generic layout. With this manual, you get the exact same content that came in the paper binder from Komatsu. That is why I only use OEM docs on my own shop floor.

If you own a D85C-21 and you are planning a transmission overhaul, a brake reline, or a valve adjustment, do not start without this manual. Access the Factory Manual from AutoRepairManuals and have the specs on your tablet or bench before you pull the first bolt.

Frequently Asked Questions

Is this the full factory manual, not a quick-start guide?

Yes, all 523 pages with every procedure, diagram, and torque chart from the original Komatsu shop manual.

What torque specs are listed in the manual?

The standard value tables cover engine and chassis fasteners. You will find torque figures for cylinder head bolts, main bearing caps, transmission case bolts, steering clutch bolts, and final drive nuts.

Does the manual cover the transmission control valve and hydraulic system?

Section 10 goes deep into the Torqflow Transmission, the Transmission Control Valve, the Lubrication Valve, and the PTO. It includes power train hydraulic system diagrams, circuit diagrams, and piping diagrams. You also get the steering and brake control valve, the steering main relief valve, and the entire counterweight hydraulic circuit. The troubleshooting section (H-mode) lists over 20 specific fault conditions, from H-1 (torque converter oil temperature high) to H-14, each with a step-by-step diagnosis path. No other document gives you this level of hydraulic detail for the D85C-21.

Will this work for a D85C-21 with a different serial number range?

This manual covers serial number 36551 and up. If your unit falls within that range, the procedures and specs apply. For earlier machines, check the serial prefix.

Related manuals you may need: Komatsu D85C-21 2005 Field Assembly Instruction, Komatsu D85C-21 2008 Workshop Manual – OEM Factory Manual, Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual. For general background on how a Manual Transmission functions, that page can help with fundamentals, but for the D85C-21 specifics, stick with this manual.