Description

Komatsu SK818-5, SK820-5 Workshop Manual – 258 Pages of Factory Data

I’ve spent 28 years in a shop, and I can tell you the difference between a manual that was photocopied from a second-generation copy and one that came off the same press as the factory binder. This Komatsu SK818-5, SK820-5 Workshop Manual is the real deal – 258 pages of original OEM documentation, not some aftermarket interpretation where torque values get shifted a couple foot-pounds because some guy keyed them in wrong. You want to pull a cylinder head on a Komatsu SK818-5? You need the actual Komatsu figures, not a guess. That’s what this manual gives you.

Skid-steer loaders are compact, but the hydraulics and drivetrain are no joke. The SK820-5 turbo adds a turbocharger, and if you don’t set the valve clearances to spec, you’ll be pulling the head again in 50 hours. This manual covers both models with separate sections for the turbo version. Page 20-1 kicks off the Testing and Adjustments section, where you’ll find procedures for checking engine speed, adjusting valve clearance, and measuring compression pressure – all with the OEM limits. I’ve used those numbers to save a machine that a parts-chucker had condemned.

Transmission and Final Drive Coverage

Transmission work on these machines means pulling the pump and motor assembly. The manual dedicates full sections in Structure and Function (page 10-1) and Removal and Installation for the P.T.O., power train, and final drive. You get exploded views, seal locations, and the critical torque values for the drive flange bolts. Don’t trust the generic chart that came with your cheap socket set – Komatsu specifies different torques for M10 and M12 bolts depending on location. The STANDARD TIGHTENING TORQUE table in the front of this manual lists the numbers for every bolt grade used on the SK818-5 and SK820-5. I keep a bookmark on that page.

How to Adjust Valve Clearance Correctly

Valve adjustment is a routine job, but if you’re off by 0.002 in. on the intake, you get a ticking noise that eventually erodes the seat. This manual walks you through the procedure step by step, including the cold-engine specification and the order to rotate the crankshaft. The Valve clearance specs are listed in the Testing and Adjustments section, and there’s a note about which feeler gauge to use. I’ve seen aftermarket manuals skip the part about checking the clearance after tightening the locknut – this one doesn’t. It’s that attention to detail that keeps a machine running.

7 Electrical Diagrams Included

Electrical gremlins are the worst on compact loaders. The manual includes seven separate electrical diagrams: engine line, frame line (standard and optional), cabin line (standard and optional), and top-cabin light line (standard and homologation). Each diagram shows wire colors, connector pinouts, and component locations. If you’re chasing a no-start condition on an SK820-5 turbo, the starting motor circuit is laid out clearly. I’ve used these to bypass a bad solenoid without pulling the whole harness. The diagrams are in the Structure and Function section, and they’re printed with enough contrast to read under a work light.

Understand the Hydraulic Circuit Before You Disconnect Anything

Hydraulics on the SK818-5 and SK820-5 are complex – there are separate circuits for the main pump, control valves (3-spool and 4-spool), CLSS, solenoid valve, accumulator, and PPC valves. The manual has dedicated subsections for each, including pressure test points and calibration procedures. Page 20-1 also covers bleeding air from the hydraulic circuits. If you don’t follow the sequence in the manual, you’ll chase air locks for hours. The Torque specifications for the hose fittings are listed next to the diagrams – no need to guess between SAE and metric conversions. Everything is imperial where applicable, with a conversion table at the front.

Testing and Adjustments: Factory Procedures

The Testing and Adjustments section (starting page 20-1) is where this manual earns its keep. It includes checking engine oil pressure, adjusting injection timing, setting fan belt tension, and calibrating the PPC valve drive pressure. There’s even a procedure for adjusting the servo-control engagement safety sensor – a common point of failure if ignored. Each test lists the required special tools (Komatsu part numbers) and the acceptable ranges. I like that the manual tells you which pressure gauge range to use – that prevents blowing out a 100 psi gauge on a 300 psi circuit. Also included: valve calibration for the control valve and checking travel deviation. These are things aftermarket manuals either simplify or omit entirely.

3 Reasons to Choose OEM Documentation

First: the torque values are verified by Komatsu engineers, not transcribed by a data-entry clerk. Second: the wiring diagrams are correct for the specific serial numbers listed (SK818-5 37BF50003 and up; SK820-5 turbo 37BTF50003 and up). Third: the step-by-step removal and installation instructions include notes about thread locker application and tightening sequence – not just a bolt diagram. I’ve had to fix jobs where someone used the wrong lubricant on cylinder head bolts because the aftermarket manual said “apply oil.” Komatsu specifies molybdenum disulfide for some bolts. This manual tells you which.

FAQ

Does this manual cover both the SK818-5 and SK820-5 turbo models?

Yes, it covers both models with specific sections for each. Separate wiring diagrams, hydraulic circuits, and cylinder head procedures.

Are the wiring diagrams in color or black and white?

They are black and white but high-contrast. Each diagram is labeled with wire colors and codes as per Komatsu’s standard. There are six separate diagrams covering engine line, frame line standard and optional, cabin line standard and optional, and top-cabin light line. I’ve used these to diagnose a bad solenoid without pulling the harness. If you need color, the OEM digital version from Komatsu is the only way – but these are clean enough to read under a trouble light.

If you need to get this machine right the first time, access the factory manual. It’s 258 pages of the same data that Komatsu dealers use. Skip the aftermarket PDFs – get the real thing here at AutoRepairManuals.

Related manuals you might need:
Komatsu SK818-5 Operators Manual – Factory OEM Operation & Maintenance”>Komatsu SK818-5 Operators Manual – Factory OEM Operation & Maintenance
Komatsu SK820-5 Service Manual – 244-Page OEM Shop Manual”>Komatsu SK820-5 Service Manual – 244-Page OEM Shop Manual
Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual”>Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual

External references:
Manual Transmission”>Manual Transmission
Manual Transmission”>Manual Transmission