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519 Telehandler
HYDRAULICS
HYDRAULIC SCHEMATICS, TROUBLESHOOTING, TESTING & ADJUSTMENT PROCEDURES GENERAL TEST PROCEDURES
INTRODUCTION This section of the Mustang 519 Telehandler service manual covers the hydraulic schematics, troubleshooting, testing and adjustment procedures.
WARNING
A single-section gear pump attached to the hydrostatic pump provides hydraulic flow for the main control valve. The main control valve directs flow for the steering control valve, joysticks and isolation valve. The hydrostatic pump provides hydraulic flow for the SAHR brake valve. The excess flow from the gear pump is directed back to the hydraulic tank.
NEVER use your hands to search for hydraulic fluid leaks. Instead use a piece of paper or cardboard. Escaping fluid under pressure can be invisible and penetrate the skin, causing serious injury. If any fluid is injected into your skin, see a doctor at once. Injected fluid must be surgically removed by a doctor familiar with this type of injury or gangrene may result.
The joysticks are located on the RH console. They direct the flow from the main control valve for boom functions.
ALWAYS wear safety glasses when checking for hydraulic fluid leaks. Escaping fluid can cause permanent eyesight damage or loss if safety glasses are not worn.
An electrical switch on the right side of the dash is connected to a solenoid that operates the SAHR park brake. When the switch is OFF, the SAHR solenoid is activated and flow from the hydrostatic pump is directed to release the park brake. When the switch is ON, the electrical signal to the solenoid is switched off. The spring on the SAHR valve control spool shifts the spool, blocks the flow from the hydrostatic pump and directs the park brake hydraulic fluid to the reservoir. The spring pressure inside the park brake applies the brake.
WARNING Construction equipment can be dangerous if improperly operated or maintained. This machine should be operated and maintained only by trained and experienced people who have read, understood and complied with the Operator’s Manual.
The steering wheel is connected directly to the Steering Control Valve. When the steering wheel is turned clockwise (right) or counterclockwise (left) the steering control unit directs flow from the priority flow divider to the steering cylinders. The Steering Mode Valve control solenoids are connected to a 3-way switch on the instrument panel. When the switch is in the neutral position, the flow from the priority flow divider is directed to the front steering cylinder. When the switch is in the 4-Wheel Mode or Crab Mode, the Steering Mode Valve directs flow to or from the front cylinder to the rear steering cylinder. The front and rear steering cylinders are in a series hydraulic circuit through the Steering Mode Valve.
WARMING THE ENGINE: Start the engine and run until the coolant temperature gauge is in the normal operating range. WARMING THE HYDRAULIC OIL: 1. Operate the attachment tilt, boom extend and boom lift cylinders at the end of their stroke for 30 seconds. 2. Repeat Step 1 until the hydraulic oil temperature is at 120°F (49°C). 3. Operate boom functions three to five times in both directions to allow warm oil to enter the circuits.
913302
601-2
PRINTED IN U.S.A.
