jcb JS300 Service Manual page 692

Section E - Hydraulics
Hydraulic System
Hydraulic Operation and Schematics
Travel - Middle Speed
K Fig 5. ( T
For schematic, E-32).
When both tracks are selected forward, servo pressure
from port 2 (LH travel lever), and port 4 (RH travel lever) 35
enters the main control valve 14 at Pa6 and Pa1
respectively, selecting the left and right hand travel spools.
Flow from pump 2 is available at the RH travel spool and
is directed to the RH travel motor via port A1 of the main
control valve 14, through the rotary coupling and in to port
P1 on the RH travel motor. Exhaust oil from the motor
enters the main control valve 14 at port B1 and is directed
by the LH travel spool to the tank port.
Flow from pump 1 is available at the LH travel spool and is
directed to the LH travel motor via port A6 of the main
control valve 14, through the rotary coupling and in to port
P2 on the LH travel motor. Exhaust oil from the motor
enters the Main control valve 14 at port B6 and is directed
by the LH travel spool to the tank port.
Servo pressure at ports Pa6 and Pa1 is also available at
travel pressure switch 51 via the shuttle valves.
Pressure is lost on both negative control ports Ps1 and
Ps2, which is sensed at the pumps which come into full
flow.
E-31 9813/5100-1 E-31