jcb JS300 Service Manual page 945

a confirm that the engine is at its maximum no-load
speed and it is in the L mode.
b Stall the dipper.
c Hold nut C and slacken locknut B. Screw nut A out
to reduce pressure or in to increase pressure.
d Once required pressure is achieved on the
pressure gauge, lock nut B against nut C.
e Make the machine safe, refer to Section E,
Service Procedures.
f Re-attach the servo hose to MRV.
4 Check the pressures.
E-284
Hydraulic System Test Procedures
9813/5100-1
Section E - Hydraulics
Main Relief Valve (MRV) Pressure
E-284