HYDRAULICS 1.39 Extension cylinder (49) The boom extension cylinder is fitted inside the boom of the machine and is supplied with operating pressure oil from a load control valve (50). Specification: Type K 50 Stroke 1971 mm Bore 80 mm Type K 60 Stroke 2111 mm Bore 80 mm Type K 70 Stroke 2917 mm Bore 80 mm Load control valve (50) The load control valve for the extension cylinder is fitted in the pressure oil supply lines, between the extension section (27) and the boom extension cylinder (49). The valve prevents any load movement in the event of hose bursts or leakage. If the valve is defective, a complete new cartridge must be fitted.
The load control valve is factory set and should never be dismantled or adjusted except for resealing. Key to Load Control Valve 1. From the extension section (27) 2. Extension cylinder (rod side) 3. Extension cylinder (full bore side) 4. From the extension section (27) 5. Pilot pressure 6. Supply pressure 7. Pressure relief