jcb JS200 Service Manual page 220

Section E
4 - 1
Main Relief Valve Pressure
Note:- P1 refers to test point on pump.
1. Prepare the machine
Put the operator levers into neutral, lower the gate lock
lever.
Start the engine and place the machine on level ground,
lower and open the dipper and set the bucket on the
ground. Stop the engine. Release the hydraulic oil tank
pressure. (See Releasing Tank Pressure).
*
1.1 Connect a 0-400 bar (0-6000 lb/in
adaptor to the P1 pressure test point, see A.
1.2 Start the engine, and confirm that the engine is at its
maximum no-load speed and it is in the S mode.
*
1.3 Operate the dipper and read the pressure gauge with the
ram at end of stroke.
2. High Pressure Setting (Pressure raising)
a. Release lock nut B and tighten the adjusting screw C
until the piston E touches the inner face marked *,
make sure, when locking screw C with lock nut B,
that nut F does not turn.
b. Tighten plug D and adjust the pressure (while
watching the pressure gauge and gradually
tightening plug D). After setting the pressure, 338
bar ± 19 bar(4977 lb/in
nut G.
3. Low pressure setting (Standard)
a. Adjust the pressure as in the high pressure setting
above by loosening plug D. If the plug C is also
loosened, the piston E moves to the plug C the
spring loading is reduced.
b. Pressure is therefore reduced. The setting pressure
is 314 bar ± 19 bar (4621 lb/in
Note: The pressure is adjusted 209 bar (3086 lb/in
revolution.
c. Lock with the plug B.
4. Stop the engine
5. Confirmation of the rated pressure
a. Start the engine, raise the r.p.m to maximum in the S
*
mode, operate the pressure raising switch in the RH
Joystick and check for leakage at the adjusted points.
*
b. Operate the dipper, hold the service in the stalled
position and then stop the control at the standard
pressure.
*
c. Press the pressure raising switch on the RH Joystick
and check the pressure.
*
d. If it needs adjusting, repeat the procedure from
step 1.3.
6. Stop the engine and relieve the pressure in the hydraulic
oil tank (see Releasing Tank Pressure) . Remove the
pressure gauge and adaptor and reconnect the hose.
9803/6400
Hydraulics
Pressure Testing
) pressure gauge and
2
± 284.4 lb/in ), lock with
2 2
± 284.4 lb/in ).
2 2
) per
2
B
Section E
4 - 1
A
*
Issue 2*