Description

Komatsu CK20-1 Workshop Manual

I’ve been turning wrenches for 28 years. If you’re trying to rebuild a CK20-1 without the factory book, you’re wasting time and risking a come-apart. Third-party manuals don’t get the charge pressure right, and they sure as hell don’t give you the OEM torque values for that track tensioner cylinder. This 298-page Komatsu CK20-1 Workshop Manual is what the factory techs used. It’s the only book I’d trust on my bench.

10 Structure and Function: Know Your Machine

Pages 10-1 through 10-108 cover every system. P.T.O., power train, frame, track tensioner idler wheel, and the track tensioner cylinder and bumper spring. You’ll find the lower idler roller, rear idler roller, and all five hydraulic circuit variants: standard, float, high-flow, super high-flow, and pattern change. The hydraulic pump section breaks down the suction safety valve, charge safety valve, charge pump, anti engine-stall control valve, shuttle valve, and travel synchronization valve. I’ve seen guys skip the AS valve adjustment and then wonder why the engine stalls under load. The manual shows you the exact procedure. Each cylinder is diagrammed with seal part numbers.

20 Testing and Adjustments: Getting the Numbers Right

Page 20-1 starts the testing section. You get normal technical data, special tool lists, engine speed checks, valve clearance adjustment, compression pressure measurement, fan belt tension, injection timing, engine oil pressure, accelerator cable stroke, PPC valve drive pressure, and PPC valve clearances. The servo-control engagement safety sensor adjustment is covered — that’s a critical safety step. Hydraulic circuit pressures, pump testing, valve calibration, travel deviation, and residual pressure elimination are all here. If you don’t bleed air from the hydraulic circuits per the factory method, you’ll chase air locks for hours. This section gives you the numbers, not guesses.

Standard Tightening Torque: Why I Trust Factory Specs

There’s a dedicated section called STANDARD TIGHTENING TORQUE. It lists the torque values for every fastener grade and size used on the machine. I’ve torqued more head bolts than most people have had hot meals, and I still check the manual. Using the wrong torque on a cylinder head or a hydraulic fitting can cost you a rebuild. This section is pulled from Komatsu’s engineering data, not a generic chart. You can also find the coating materials table and the weight table — useful when you’re hoisting the cab off.

Electrical Diagrams: Tracing the Wires Without the Smoke

The manual includes 20+ pages of electrical diagrams covering engine line, frame line, cabin line, and top-cabin light line — both standard and optional. Each diagram is labeled with component IDs and wire colors. If you’re working on a Manual Transmission in another vehicle, the principles of tracing circuits apply here too. But for the CK20-1, these diagrams are specific to the machine’s solenoid valves, accumulator, pattern change valve, and PPC valves. Don’t use a generic wiring schematic — it’ll lead to shorts and fried ECUs.

Source Validity: OEM vs Aftermarket Reprints

This is an original OEM Komatsu shop manual, not a scanned copy or a third-party reprint. The document ID is WEBM006400. It includes the REVISED PAGES table with revision marks — aftermarket books never include that. If you’ve ever tried to use a Haynes-style manual for a skid-steer, you know the frustration. This factory manual gives you the exact procedures, part numbers, and torque specs that Komatsu trained technicians use. Check out related manuals like Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual or Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual for other models. For a larger wheel loader manual, see Komatsu PW95R-2 Workshop Manual – 520 Pages of Factory Specs.

What This Manual Covers (and What It Doesn’t)

The manual is divided into five main sections: Structure and Function (10), Testing and Adjusting (20), Removal and Installation (30), Maintenance Standard (40), and Other (90). The removal and installation chapter includes engine hood, cab, battery, starting motor, and more. The maintenance standard section gives wear limits and inspection intervals. If you’re looking for engine rebuild specs, the compression pressure and valve clearance adjustments are in section 20. The manual does not cover the engine disassembly in full — that’s in a separate engine manual. But for the CK20-1 chassis, hydraulic system, and powertrain, this is complete.

Does this manual cover the hydraulic circuits?

Yes. It covers standard, float, high-flow, super high-flow, and pattern change circuits. Each circuit has its own diagram and pressure specs.

What torque values are listed?

The STANDARD TIGHTENING TORQUE section gives fastener torque for all standard bolts. Additionally, specific torque values for hydraulic fittings, cylinder mounting bolts, and track tensioner components are listed in the relevant sections. For example, the track tensioner cylinder requires a specific torque during assembly — it’s not just “tighten until snug.” The manual spells it out.

Is this the same manual the dealer uses?

Yes. This is the OEM Komatsu shop manual, part number WEBM006400. Dealers use this exact document for warranty repairs and diagnostics. It includes the revised pages table with the latest updates.

How many pages?

298 pages. Covers structure, testing, removal, and maintenance standards. Enough to get the job done right.

Torque matters. Cylinder pressures matter. Electrical diagrams matter. If you’re serious about fixing your CK20-1 without guesswork, get the factory manual. Access the Factory Manual now and keep it on your tablet or print it out. You’ll thank yourself when you’re setting that charge pressure or adjusting the PPC valve clearances.