This is the factory service manual for the Mustang ML52 wheel loader, covering the 520 and 620 machines (models 303 58 and 304 59) built on Perkins 1004-4 diesel engines, including the 1004-4 LR, 1004-4 HR, and low-emission 1004-42. Published as part number 50940190, it runs 194 pages.
Coverage includes engine service, the hydrostatic drive and hydraulic circuit, the ZF APL-R 735 planetary front axle, brakes, the steering system, and the complete electrical system with wiring harness diagrams and fuse sizes. Specifications, maintenance kits, and torque values run throughout.
With this PDF you can adjust valve clearance, pressure-test the hydrostatic and work hydraulics, synchronize and bleed the steering, service the axles and brakes, and trace wiring faults against the diagrams. It gives an owner or independent mechanic dealer-level detail for these loaders.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| General & Service Materials | 3 | Specifications / Controls, Servicing Material, Sealing Kits, Lubricants, Engine, Fuel Lines, Cooling, Frame |
| Specifications (520 / 620) | 4-16 | Specifications Controls, Specifications Wheel Loaders 520 / 620, Frame, Engine, Engine 520, Engine 620, Low-Emission Engine 520 |
| Maintenance Kits | 17-19 | Service Kit for “1st Inspection”, Maintenance Kit for Maintenance Plan “B”; “C” and “2nd Inspection”, Maintenance Kit for Maintenance Plan “D” |
| Maintenance & Lubrication | 20-21 | Oil and Filter Changes, Inspection Work, Lubrication, Functional Check, Leakage Check |
| Engine | 22-32 | Specifications, Engine 520, Engine 620, Valve Tip Clearance (Checking and Adjusting, Four Cylinder Engines), Removing and Fitting the Rocker Assembly |
| Fuel System | 33-34 | Group 08, Fuel Lines, Fuel Feed System 520 / 620 Wheel Loaders |
| Cooling System | 35-36 | Group 15, Cooling, Cooling System 520 / 620 Wheel Loaders |
| Frame | 37-38 | Group 20, Vehicle Frame Wheel Loaders 520 / 620 |
| Hydrostatic Drive | 39-88 | Hydrostatic Drive Wheel Loaders 520 / 620, Hydraulic Circuit Wheel Loaders 520 / 620, Temperature Controller 520/620 |
| Front Axle | 89-94 | Front Axle (Specifications and Set Values for Zf Apl-R 735 Planetary Steering Axle, Lubrication and Service Instructions) |
| Brakes | 95-98 | Group 24, Brake System 520 / 620 Wheel Loaders, Brake Diagram 520 / 620 Wheel Loaders, Hydr Fixed-Calliper Brake 520 / 620 Wheel Loaders |
| Rear Axle | 99-101 | Group 26, High Speed 520 / 620 Wheel Loaders |
| Steering | 102-106 | Specifications, Synchronising the Steering, Bleeding the Steering System |
| Electrical System | 107-139 | Fundamentals (Ohm's Law; Power, Measuring Equipment, Measuring Methods, Terminal Description, Pin Interface - Cab / Frame, 20 Series) |
| Wiring Harness & Electronics | 140-149 | Electronics Box Models 300 55/301 56/302 57/303 58/304 59, Cable Assignment, Main Wiring Harness Frame 0 38 330 00 10, Assignment Table 21 Pole Interface, Wiring Harness |
| Wiring Harness (Instrument Panel) | 150-155 | Electrical System Overview, Wiring Harness Instrument Panel 0 00 080 39 64, Wiring Harness Details |
| Electrical Diagrams | 156-163 | Wiring Harness Instrument Panel 0 00 080 39 64, Ref No Description Section, Fuse Sizes, Electrical Diagram Models 303 58/304 59 |
| Cab | 164-165 | Group 34, Removing the Front Wiper Motor 520 / 620 Wheel Loaders |
| Hydraulic System | 166-184 | Group 36, Hydraulic System 520 / 620 Wheel Loaders, Work Hydraulics 520 / 620 Wheel Loaders, Hydraulic Tank 520 / 620 Wheel Loaders |
| Hydraulic Diagrams | 185-188 | Hydraulics Diagram 520 / 620, Notes |
| Cab Heating & Torque Specs | 189-194 | Group 41, Cab Heating, Heating 520 / 620 Wheel Loaders, Torque Specifications, Hydraulic Fittings with Various Seals, With Coarse-Pitch Thread, With Fine-Pitch Thread |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Wheel nut torque | 420 ±20 Nm | p. 10 |
| Hydraulic oil filter insert replacement interval | every 12 months or 1200 service hours | p. 21 |
| Air filter insert replacement interval | every 12 months or 1200 service hours | p. 21 |
| Fuel filter replacement interval | every 50 hours | p. 21 |
| Engine coolant capacity | About 15 ltr. | p. 18 |
| Thermostat minimum opening distance | 9 mm | p. 29 |
| Battery voltage and capacity | 12 V, 100 Ah | p. 9 |
| Tire pressure (front) for 14.5-20 MPT E91-2 10PR 132 E | 2.25* bar | p. 9 |
| Maximum hydraulic oil temperature | 85°C | p. 70 |
| Main pressure relief valve pressure (work hydraulics) | 235 bar | p. 73 |
| Lift ram piston screw torque | 1000 Nm | p. 183 |
| Engine 520 Output | 53 kW / 72 HP, 2.200 rpm | p. 5 |
