MOUNTING GP-STARTING MOTOR 2106434 - Caterpillar

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Boom cylinder lines group (1) Supply line for boom cylinder rod end (2) Boom lowering control valve (3) Supply line and return line for boom cylinder head end (4) Pilot line to boom lowering control valve (5) Drain line to hydraulic tank
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Hydraulic schematic of boom lowering control valve (6) Pressure relief valve (7) Check valve (8) Port to head end of boom cylinder (9) Control valveThe boom lowering control valve has two functions:
A check valve prevents the boom from falling if a hydraulic supply line or a supply tube to the boom cylinder fails.
An adjusting screw allows the operator to manually lower the boom when the engine is shut down.Boom Raise Operation
When the boom pilot control valve is moved to the BOOM RAISE position pump oil from line (10) flows into boom lowering control valves (2). The pump oil passes through check valve (7) and flows into the head end of the boom cylinders.The oil in the rod end of the boom cylinders goes through line (1), and back to the hydraulic tank through the boom control valve.When the implement control lever is moved to the NEUTRAL position, the boom cylinders are held in the raised position. Check valve (7) prevents the oil in the head end of the boom cylinders from flowing out of the boom cylinders.Boom Lower Operation
When the implement control valve is moved to the BOOM LOWER position, pilot oil is sent through line (4) to the boom lowering control valve. The pilot oil shifts check valve (7) and control valve (9). Oil from the head end of the boom cylinders flows through boom lowering control valves (2) and line (10) to the hydraulic tank.At the same time, main pump oil from the main control valve flows through line (1) to the rod end of the boom cylinders. Relief Operation of the Cylinder Head End
When the boom is pushed downward by an outside force the oil pressure in the head end of the cylinder increases. The oil pressure is sensed at relief valve (6) of the boom lowering control valve. When the relief valve opens the oil flows back to the hydraulic tank. Note: The relief valve is set to open at 36300 500 kPa (5265 72.5 psi).Manual Boom Lower Operation
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(10) Supply line and return line for boom cylinder head end (11) Line to the relief valve (12) Supply line and return line for boom cylinder rod end (13) Return line to tankA boom lowering control valve is installed on the head end of both boom cylinders. The boom lowering control valve allows the operator to manually lower the boom if the engine is stopped. The boom lowering control valve also prevents the boom from falling if there is an oil leak in the hydraulic line of the boom.
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(15) Locknut (16) Adjusting screwThe oil flows from the head end of the cylinder through line (11) to the bleeder valve. When locknut (15) and adjusting screw (16) are slowly