Komatsu PW98MR-8: steering, separate swing pump and supported lift charts

PW98MR-8 steering and travel selections

The PW98MR-8 puts three steering patterns on the same wheeled undercarriage: front-wheel steering, coordinated four-wheel steering and crab travel. The steering choice changes the maneuver, not just the turning circle. Crab mode shifts the machine sideways at an angle while keeping its body orientation.

Komatsu requires simultaneous operation of two switches when changing steering mode, with a green confirmation lamp. Check the selected pattern before interpreting a steering complaint.

Front-axle oscillation has a separate hydraulic lock controlled through the monitor. Selecting four-wheel steering does not itself describe the axle's locked state. The travel drive is hydrostatic, with a synchromesh mechanism providing two ranges.

The specification then separates working speeds from travelling speeds. A quoted top-road speed is a poor description of how the excavator should be positioned for digging.

The swing pump is not the attachment pump

Komatsu's hydraulic diagram assigns the boom, arm, bucket, undercarriage and travel functions to a variable-displacement axial-piston pump. Swing uses a fixed-displacement gear pump of its own. Adding their published flows together would misdescribe the supply available at an attachment connection.

The separate swing relief also differs from the work-and-travel setting.

The HCU-A auxiliary circuit is listed as standard in this European brochure. HCU-C, which adds another auxiliary line and hydraulic quick-coupler preparation, is optional. A machine with hoses on its arm therefore needs its circuit identified before a buyer assumes the extra coupling controls are present.

Read the support arrangement above the lift chart

Blade-only, stabilizer-only and blade-plus-stabilizer machines carry different operating weights. Komatsu's lifting page divides the charts again: supports raised, rear blade down, or front blade and rear stabilizers down. The front and side columns are separate within each chart.

They are not interchangeable capacities.

The chart specifies an additional counterweight, twin tires and a particular bucket. Its lift point is a hypothetical hook behind the bucket. Removing the bucket, linkage or cylinder changes the calculation by the respective component weights; it does not justify taking a capacity from a different support arrangement.

The notes also specify level, firm ground and the applicable load-handling equipment. Use the chart that matches the actual arm and setup.

Which European engine sheet applies?

Publication WESS007502, dated December 2015, identifies a SAA4D95LE-5 and EU Stage IIIA. It gives separate ISO 14396 and SAE J1349 power ratings at the same rated speed. The archive product page currently uses a different emissions label.

For this brochure configuration, the printed Stage IIIA designation is the supported claim; an archive label alone is insufficient evidence of different exhaust equipment on a particular machine.

Source: Komatsu PW98MR-8 European brochure WESS007502, steering, hydraulics, lifting and equipment pages.