Track links wearing out early, a code 8002 on the display, or a dozer that will not move after a travel drive failure: this is the book for those jobs. It is the Liebherr Service Manual for the PR724, PR734, PR744, PR754, PR764 Litronic crawler dozers, Series 4, index issue 02.2010. It comes from Liebherr-Werk Telfs, runs 2567 pages and is in English.
Every day the dozer sits, you pay for an idle operator and the contract falls further behind. The book covers engine data by serial range, the hydrostatic travel and working hydraulics, and LinDiag diagnostics. It also covers the final drives, track and blade.
Check your F/N against the right engine and component pages before you call the dealer. Then the part you order is the one that fits.
What's Inside This Liebherr PR724–PR764 Litronic Manual
| System | Pages | Key Topics |
|---|---|---|
| General Information | 13-56 | Safety Guidelines, Service Items and Lubricants, Tightening Torques, Conversion Chart, Storage Guidelines, Weights |
| Special Tools / Application Guidelines | 57-90 | Special Tools, Repair Welding, Installation of Slip Ring Seals |
| Technical Data / Maintenance Guidelines | 91-192 | Technical Data per Model and Serial Range, Maintenance and Inspection Schedules and Guidelines |
| Engine | 193-220 | Engine Data Pages, Fan and Cylinder Configuration, Diesel Particle Filter Installation, Engine Mount |
| Coupling and Splitterbox | 221-244 | Engine Coupling, Splitterbox, Pump Output Couplings |
| Travel Hydraulic | 245-450 | Data Page, Description, Function, Test and Adjustment, Component Location |
| Working Hydraulic | 451-622 | Regulating Pump, Pilot Control, Control Valve Block, Quick Drop Unit, Overspeed Safety, Blade Release, Check and Adjustment |
| Hydraulic Components | 623-814 | Variable Pump, Variable Motor, Regulating Pump, Double Gear Pump, Control Valve Block, Hydraulic Cylinders |
| Electrical System - Plans | 815-1528 | Code Letter Explanations, Function List, Fuses, Current Flow Diagrams, Component Arrangement |
| Electrical System - Descriptions | 1529-1620 | Instrument Panel, LinDiag Diagnostic Software, Adjustments, Service Code Lists |
| Final Drive | 1621-1706 | Data Page, Design and Function, Sectional View |
| Track Components | 1707-1782 | Track Wear and Evaluation, Inspection Checklist, Track Pad Screw Torques, Track Roller Frame, Idler and Tension Unit |
| Attachments - Front and Rear | 1783-1856 | Straight Blade, 6-Way Blade, Hydraulic Cutting Angle Adjustment, Ripper |
| Main Frame Components | 1857-1894 | Cooler Arrangement, Hoist Cylinder Suspension, Equalizer Bar |
| Tank Arrangement | 1895-1950 | Hydraulic Tank, Fuel Tank, Battery Box |
| Operator's Platform | 1951-1980 | Heater and Blower, Air Conditioning, Operator's Seat |
| Special Equipment / Additional Documentation | 1981-2567 | Special Equipment, Travel and Working Hydraulic Schematics, Additional Electrical and Hydraulic Sheets |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| PR724 | ||
| PR724 engine (F/N 7697 to 9199) | Liebherr D924 TI-E A2, 4 cylinder in-line intercooled, 6.6 l, 118 kW (160 HP) to ISO 9249, rated 1800 rpm | p. 95 |
| PR724 engine (from F/N 9200) | Liebherr D934 L A6, 7.0 l, 120 kW (163 PS) to ISO 9249 | p. 97 |
| PR724 firing order (D924 TI-E A2) | 1-3-4-2 | p. 95 |
| PR724 fuel tank capacity | 365 l | p. 95 |
| PR724 travel pumps | 2 x HPV 105, max. 2 x 233 l/min, max. operating pressure 420 bar | p. 95 |
| PR724 track pad screws 3/4-16 UNF 12.9 (Intertractor, as of 2010) | 320 +/- 15 Nm + 120 degrees | p. 1710 |
| PR734 | ||
| PR734 engine (F/N 6200 to 8219) | Liebherr D926 TI-E A2, 9.96 l | p. 105 |
| PR734 engine (from F/N 8220) | Liebherr D936 L A6, 10.5 l, 150 kW (204 HP) to ISO 9249 | p. 107 |
| PR744 | ||
| PR744 engine | Liebherr D936 L A6, 10.5 l, 185 kW (252 HP) to ISO 9249 | p. 111 |
| PR754 | ||
| PR754 engine | Liebherr D946 L A6, 12 l, 250 kW (340 PS) to ISO 9249 | p. 113 |
| PR764 | ||
| PR764 engine (from F/N 9506) | Liebherr D9508 A7, 16.2 l, 310 kW (422 PS) to ISO 9249 | p. 117 |
| All Models | ||
| Track chain sag between idler and carrier roller | 30 to 40 mm, depending on track type | p. 135 |
Liebherr PR724–PR764 Litronic Common Problems This Manual Covers
Track components wearing fast
Too much track tension causes increased track component wear. Drive forward on level ground, stop, and measure chain sag between the idler and the carrier roller. The maintenance guidelines give 30 to 40 mm, depending on track type. The Track Components section then covers wear evaluation, the inspection checklist and the idler and tension unit.
Manual Section: Technical Data / Maintenance Guidelines; Track Components p. 135Service code 8002: engine oil pressure too low warning
Code 8002 means engine oil pressure too low. Check the oil level first. If the level is correct, check the wiring and then the sensor before you blame the engine. Electrical System - Descriptions has the service code lists and LinDiag. The plans section has the current flow diagrams for tracing the circuit.
Manual Section: Electrical System - Descriptions p. 1596Diesel particle filter exhaust counter pressure does not drop during regeneration
Turn the diesel engine off, wait approx. 30 minutes and repeat the regeneration. If the counter pressure still stays up, read the service code on the display and follow the steps in section 10.2. The Engine section shows the diesel particle filter installation.
Manual Section: Engine; Electrical System - Descriptions (section 10.2) p. 211Machine cannot be moved after a travel drive failure
The brake release procedure has you run a hose from connection B to C with the accumulator under pressure. That releases the travel drive brake and the parking brake.
Manual Section: Travel Hydraulic; Final Drive p. 313Frequently Asked Questions
Which engine is in my PR724 or PR734?
It depends on the F/N on the plate. A PR724 from F/N 7697 to 9199 runs the Liebherr D924 TI-E A2, a 6.6 l four cylinder with firing order 1-3-4-2. From F/N 9200 it has the D934 L A6 at 7.0 l. The PR734 has the D926 TI-E A2 up to F/N 8219 and the D936 L A6 from F/N 8220. Read the plate before you order filters or gaskets. p. 95
Does the book list the service codes the display shows?
Yes. The electrical descriptions section covers the instrument panel, the LinDiag diagnostic software, adjustments and the numeric service code lists. 8000 is the engine ECU collective error and 8002 is engine oil pressure too low. Look the number up before you start pulling sensors. p. 1596
What travel pumps does the PR724 use?
Two HPV 105 variable pumps, each delivering up to 233 l/min, with a max. operating pressure of 420 bar. The Hydraulic Components section covers the variable pump, variable motor, regulating pump and double gear pump. The Travel Hydraulic section has the test and adjustment steps. p. 95
Are the track pad screw torques in the book?
Yes, they are listed by model and screw type. For the PR724 with 3/4-16 UNF 12.9 screws (Intertractor, as of 2010) the figure is 320 +/- 15 Nm plus 120 degrees. p. 1710
Does it cover the 6-way blade and the ripper?
Yes. The front and rear attachments section covers the straight blade, the 6-way blade, the hydraulic cutting angle adjustment and the ripper. The main frame pages add the hoist cylinder suspension and the equalizer bar. p. 1783
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