CAP-VALVE SPRING 3227485 - Caterpillar

Pilot Hydraulic Schematic
Illustration 1 g03871124
Pilot Hydraulic System
(1) Shift piston
(2) Modulation valve
(3) First gear valve
(4) Oscillating axle cylinders
(5) Fore boom lowering control valve (if equipped)
(6) Boom lowering control valve (left)
(7) Boom lowering control valve (right)
(8) Stick lowering control valve
(9) Boom lowering control valve (left) - for ride control (if equipped)
(10) Boom lowering control valve (right) - for ride control (if equipped)
(11) Control valve (multi combined anti drift valve - if equipped)
(12) Auxiliary valve directional solenoid (if equipped)
(13) Auxiliary flow valve port "B" (if equipped)
(14) Auxiliary flow valve port "A" (if equipped)
(15) Proportional reducing valve (second high-pressure control - if equipped)
(16) Pilot filter
(17) Steering priority valve
(18) Boom down pilot pressure switch
(19) Proportional reducing valve (second high-pressure control - if equipped)
(20) Check valve (boom rod end) - port "B"
(21) Check valve (boom head end) - port "A"
(22) Drift reduction valve (bucket valve - port "A")
(23) Swing brake
(24) Joystick pattern change valve
(25) Medium pressure pilot pump
(26) Swing pump
(27) Main pump
(28) Hydraulic oil tank
(29) Relief valve (medium pressure creation)
(30) Relief valve (pilot pressure creation)
(31) Gear shift solenoid valve
(32) Travel direction solenoid valve
(33) Travel activation solenoid
(34) Main pump limit solenoid
(35) Swing pump control pressure switch
(36) Swing pump control solenoid
(37) Travel motor swash plate angle limit solenoid
(38) Pilot manifold
(39) Oscillating axle solenoid
(40) Swing brake solenoid
(41) Heavy lift solenoid (if equipped)
(42) Implement lockout solenoid
(43) Pilot system oil pressure sensor
(44) Main Pump Pressure Switch
(45) Medium pressure pilot pump displacement control solenoid
(46) Auto brake safety valve
(47) Right joystick pilot control
(48) Travel pedal
(49) Fore boom pedal (if equipped)
(50) Left joystick pilot control
(51) Blade/Stabilizer control lever
(52) Medium pressure control valve
(53) Smart boom control solenoid (if equipped)
(54) Pilot oil swivel
(55) Main oil swivel The pilot manifold is located behind the cab and below the step leading to the top of the machine.The pilot manifold performs many functions. Solenoid valves that are installed in the pilot manifold direct pilot oil flow to components on the machine. The pilot manifold performs the following functions:
Controls transmission clutch engagement for gear selection
Supplies pilot oil to the joysticks and pedals in order to operate the main control valve spools
Activates the heavy lift option
Release the swing parking brake
Generate power shift pressure for controlling the medium pressure/pilot pump
Locks and unlocks the oscillating axle cylinders
Controls travel motor displacement change valve
Limits the swing system pressure relief valve
Supplies oil to the medium pressure control valvePiston Pump
Illustration 2 g03872605
Right side view
(25) Medium pressure pilot pump A pressure signal line is connected from the pump outlet to the pilot manifold Q+ solenoid and back to pump port "X". At higher oil flow demand (medium pressure valve activated or pilot pressure too low) the Q+ solenoid activates and the pump adjusts to a higher displacement.Medium pressure pilot pump (25) supplies oil flow to the medium pressure and pilot hydraulic systems. Oil flow from the pump is used to operate various components.The oil from pump (25) flows to pilot oil filter (16) and to displacement control solenoid valve (45).A controlled amount of oil from displacement control solenoid valve (45) flows back to pump (25) in order to