Straight from Liebherr and laid out in the factory's own eleven chapters, this 342-page Liebherr PR 721, PR 731, PR 741 service manual PDF covers all three crawler dozers in the range. Drive hydraulics alone fill roughly a quarter of the book, with operating pressures, test instructions and hydraulic schematics tracing the travel circuit, while the electrical chapter carries wiring diagrams for following a dead circuit back to its source. Your undercarriage work is covered too: running gear wear limits, track adjuster and lower roller service, and travel drive removal through reassembly. Measure track pins and bores against the factory figures: 3 mm is the wear limit, and at 5 mm the parts get renewed. Every hour a dozer sits idle costs you. Exploded views show how each assembly goes together, so you order the right component the first time, and bookmarks plus searchable text jump straight to any chapter.
What's Inside This Manual
| System | Pages | Key Topics |
|---|
| Technical Data | 7-16 | Technical Data PR 721, Technical Data PR 731, Technical Data PR 741 |
| Engine | 17-24 | Maintenance Chart PR 721, Maintenance Chart PR 731, Maintenance Chart PR 741 |
| Drive Hydraulic | 25-114 | Operating Pressures, Test Instructions, Travel Hydraulics Components |
| Working Hydraulic | 115-146 | Table of Pressures, Test Instructions, Hydraulic Components |
| Electrical System | 147-194 | Electrical System Components, Electrical System Diagrams |
| Track Drive | 195-220 | Travel Drive Removal, Travel Drive Disassembly, Travel Drive Assembly |
| Running Gear | 221-284 | Wear Limits, Track Adjuster, Lower Roller |
| Track Frames | 285-306 | Lower Roller Frame Removal, Lower Roller Frame Installation, Swing Beam |
| Attachment | 307-324 | Pusher Frame Removal, Pusher Frame Adjustment, Pusher Frame Installation |
| Tools | 325-332 | Ring Nut Wrench, Filling Apparatus, Adapter Flange |
| General Information | 333-342 | Tightening Torques, Ermeto Unions |
Quick Reference Specifications
| Specification | Value | Page |
|---|
| All Models |
| Track tension | 2 cm | p. 22 |
| Track pin and bore wear limit | 3 mm | p. 225 |
| Track pin and bore renewal limit | 5 mm | p. 225 |
| Track tension sag | 2 cm | p. 235 |
| PR 721 Drive sprocket tooth flank wear | 6-8 mm | p. 229 |
| PR 731 Drive sprocket tooth flank wear | 6-8 mm | p. 229 |
| PR 721 M/103, 731/102, 741/106 |
| Reservoir of hydraulic circuit supply unit operating pressure | 30 bar ± 2 bar | p. 133 |
| PR 721 M/155 |
| Max. operating pressure (supply pressure) | 18 bar | p. 133 |
| PR 741 |
| Tightening torque for M 24 x 3 shank bolts (Strength rating 10.9) | 1 046 Nm | p. 334 |
| PR 721 |
| Engine Oil Capacity | 18 liters | p. 9 |
| Fuel Tank Capacity | 260 liters | p. 9 |
| Max. travel speed | 10.5 km/h | p. 10 |
