JLG 600SC_660SJC Service Manual - Manual (Page 286)

SECTION 8 - HYDRAULICS
8-26 – JLG Lift – 3121157
Placing Pump Back Into Service
1. If shop test stand is available, the following proce-
dure for testing rebuilt pumps is recommended:
a. Mount pump on test stand making sure that the
proper level of clean oil is available in the reser-
voir. Check suction line for leaks and obstruc-
tions.
b. Start pump and run for three minutes at zero
pressure.
c. Intermittently load pump to 500 P.S.I. for three
minutes.
d. Intermittently load pump to 1000 P.S.I. for three
minutes.
e. Intermittently load pump to 2000 P.S.I. for three
minutes.
f. Remove pump from test stand and check for
freeness of drive shaft. Check pump for signs of
external leakage.
2. If shop test stand is not available, the following pro-
cedure for testing rebuilt pumps is recommended:
a. For engine driven pumps, mount pump on
equipment and run pump at 1/2 engine speed at
zero pressure for three minutes.
b. By operating control valve, build pressure inter-
mittently for three minutes.
c. Increase engine speed to full throttle and build
pressure intermittently for three minutes.
d. Stop engine and check pump for external leaks.
8.9 VARIABLE PUMP
Ports and Pressure Gauges
Proper servicing of pumps and motors requires that pres-
sure be measured and monitored at various points in the
hydraulic circuit. The Series 42 pump has several loca-
tions at which to take these measurements. The following
outlines show the locations of the various gauge ports.
The following table shows the recommended gauge size
and the fitting size for each port.
NFPE Control
The 3-position FNR control and the electric and hydraulic
non-feedback proportional (NFPE and NFPH) controls are
non-feedback type controls. The FNR and NFPE controls
consist of modules mounted on the pump housing. The
hydraulic input for NFPH is received through ports on the
top of the pump [9/16–18 SAE O-ring fitting].
The non-feedback controls are set at the factory. The con-
trol modules can be removed to clean the ports and
change the O-rings.
The orifice plugs for the FNR and NFPE are located inside
the servo piston covers. The orifice plugs for the NFPH are
located in the NFPH ports. Orifice plugs may be cleaned
or replaced.
Table 8-4. Recommended Gauge Size
Gauge
Port
Name
Pressure
Measured
Recommended
Gauge Size
Fitting
PSI Bar
M1 & M2 System
Pressure
Ports A & B
10000 600 9/16-18 ORF
M3 Charge 1000 60 3/4-16 ORF
M4 & M5 Servo 1000 60 9/16-18 ORF
L1 & L2 Case 500 35 1-1/16-12 ORF
S Charge Pump
Inlet Vacuum
30 in. Hg Vac. 1 1-1/16-12 ORF