jcb JS300 Service Manual page 950

Dipper Ram
1 Prepare the Machine
a Operate the dipper out and lower the boom to set
the bucket on the ground.
Fig 14.
b Make the machine safe, refer to Section E,
Service Procedures.
c Connect a 0 - 400 bar (0 - 6000 lb/in
gauge and adaptor to port TP2 on the hydraulic
pump.
2 Increase MRV Pressure, refer to Section E, Service
Procedures.
3 Start the engine, lower the gate lock lever and run the
engine at minimum no-load speed in the E mode.
4 Pressure Adjustment
a Raise the boom enough to allow the Dipper to
move freely.
b Move the dipper fully out and then continue to
operate the control lever, as at A.
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Hydraulic System Test Procedures
A
B
C030150-1
2 ) pressure
c The pressure gauge reading (Dipper Out) should
be compared to the technical data at the start of
the section. If it is outside the limits, adjust the
ARV.
d Move the dipper fully in and then continue to
operate the control lever, as at B.
e Compare the pressure gauge reading (Dipper In)
to that stated in the technical data section at the
start of the section. If it is outside the limits, adjust
ARV.
Note: For accurate setting, the pressure should be
adjusted up to the required level. Release lock nut X.
Adjust setting screw Y to indicate a pressure below the
required level and then bring the pressure back up for final
setting. Tighten lock nut X.
5 Restore Original MRV Pressure, refer to Section E,
Service Procedures.
9813/5100-1
Section E - Hydraulics
Auxiliary Relief Valves
Fig 15.
Fig 16.
C002700-C1
312460-C1
E-289