Reactivación De Equipo

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HYDRAULIC SYSTEM
NOTE
Hydraulic systems on all loader backhoes are similar and operate basically the same way.
Hydraulic system for loader backhoes with Serial Numbers 319995 thru 342573 is shown.
See Section XX, Hydraulic and Fluid Systems (page 2-1189), for hydraulic system
diagrams.

TRANSMISSION CASE
·Considered part of transmission system.
·Acts as hydraulic fluid reservoirfor all hydraulic system components.

SPEED GEAR ASSEMBLY (REVERSER) CLUTCH CONTROL VALVE
·Considered part of transmission system.
·Clutch pressure valve spool routes excess hydraulic fluid through oil line to hydraulic pump.

CLUTCH CONTROL VALVE-TO-HYDRAULIC PUMP INLET OIL LINE
·Routes hydraulic fluid from speed gear assembly (reverser) clutch control valve, and oil filter reliefvalve-to-clutch
control valve adapter oil line, to hydraulic pump inlet.

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HYDRAULIC PUMP
·Variable displacement, constant pressure pump with eight radially arranged pistons.
·Inlet fed by hydraulic oil filter relief valve and speed gear assembly (reverser) clutch control valve through low pressure oil lines.
·High pressure output hydraulic fluid routed through high pressure oil lines topressure control valve, hydraulic accumulator, and steering valve.
·Passes excess low pressure hydraulic fluid directly to hydraulic oil cooler through low pressure oil line.
·Excess hydraulic fluid from hydraulic pump shaft lubrication is routed to transmission case sump through drain line to protect pump shaft seal from pressure build-up.
·Delivers on demand to maintain hydraulic systempressure for operation of all hydraulic system components.


HYDRAULIC PUMP STROKE CONTROL SOLENOID VALVE
·Considered part of electrical system.
·Normally closed solenoid is opened when starter switch is closed to bypass hydraulic pump discharge oil into pump crankcase during engine cranking.
·Reduces load on engine to make starting easier.

HYDRAULIC PUMP-TO-SPEED GEAR ASSEMBLY (REVERSER) SEALDRAIN LINE
·Routes excess hydraulic fluid from hydraulic pump shaft lubrication to transmission case sump.
·Protects hydraulic pump shaft seal from pressure build-up.

HYDRAULIC PUMP-TO-HYDRAULIC OIL COOLER OIL LINE
·Routes low pressure hydraulic fluid not needed by hydraulic pump directly to hydraulic oil cooler.

HYDRAULIC OIL COOLER
·Considered part of transmission system.
·Finned coreair cools hydraulic fluid routed to it through low pressure oil line from hydraulic pump.
·Routes cooled hydraulic fluid through low pressure oil line to clutch control valve.

HYDRAULIC OIL COOLER-TO-CLUTCH CONTROL VALVE OIL LINE
·Routes cooled low pressure hydraulic fluid from hydraulic oil cooler to speed gear assembly (reverser) clutch control valve.


HYDRAULIC PUMP-TO-PRESSURECONTROL VALVE OIL LINE
·Routes high pressure hydraulic fluid from hydraulic pump, to hydraulic pump pressure line tee-to-hydraulic accumulator oil line, and pressure control valve.

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HYDRAULIC PUMP PRESSURE LINE TEE-TO-HYDRAULIC ACCUMULATOR OIL LINE
·Routes high pressure hydraulic fluid from hydraulic pump pressure line tee, through hydraulic accumulator tee, where it isconnected to hydraulic accumulator and accumulator tee-to-steering valve oil line.

HYDRAULIC ACCUMULATOR
·Connected through high pressure oil lines to hydraulic pump, steering valve, and pressure control valve.
·Pressure tight cylinder with sealed floating piston.
·One side of floating piston is precharged with dry nitrogen.
·Other side of floating piston is filled with hydraulic fluid fromhydraulic system.
·As hydraulic system fluid pressure builds up, dry nitrogen is compressed to equalize pressure on both sides of floating piston.
·Compressed dry nitrogen absorbs surge pressure when hydraulic cylinders reach end of travel or control valves are returned to neutral.
·When hydraulic fluid pressure drops due to demand on system or engine shutdown, dry nitrogen expands to slow...