Pump adjustment, Pump adjustment -64 – JLG 340AJ Service Manual User Manual
Page 222
SECTION 5 - HYDRAULICS
5-64
– JLG Lift –
3121259
Pump Adjustment
Read through the entire topic before beginning a service
activity. Refer to Figure 5-31., Port Locations, for location of
gauge ports and suggested gauge size.
CONTAMINATION CAN DAMAGE INTERNAL COMPONENTS AND VOID YOUR
WARRANTY. TAKE PRECAUTIONS TO ENSURE SYSTEM CLEANLINESS WHEN
REMOVING AND REINSTALLING SYSTEM LINES
1.
With the prime mover off, thoroughly clean the outside
of the pump.
2.
If removing the pump, tag each hydraulic line. When you
disconnect hydraulic lines, cap them and plug each
open port to prevent contamination.
3.
Ensure the surrounding area is clean and free of contam-
inants like dirt and grime.
4.
Inspect the system for contamination.
5.
Check the hydraulic fluid for signs of contamination: oil
discoloration, foam in the oil, sludge, or metal particles.
6.
If there are signs of contamination in the hydraulic fluid,
replace all filters and drain the hydraulic system. Flush
the lines and refill the reservoir with the correct filtered
hydraulic fluid.
7.
Before re-installing the pump, test for leaks.
CHARGE PRESSURE RELIEF VALVE ADJUSTMENT
NOTE:
Ensure charge pressure is properly set before checking
pressure limiter.
1.
Install a 50 bar [1000 psi] pressure gauge in charge pres-
sure gauge port M3. Install a 10 bar [100 psi] gauge at
case pressure port L1, L2, or L3. Operate the system with
the pump in neutral (zero displacement) when measur-
ing charge pressure.
2.
The table shows the acceptable pump charge pressure
range for some nominal charge relief valve settings
(refer to model code located on serial number plate).
These pressures assume 1800 min-1 (rpm) pump speed
and a reservoir temperature of 50°C [120°F],and are ref-
erenced to case pressure.
NOTE:
Listed pressures assume a pump speed of 1800 rpm and
charge flow of 26.5 l/min [7 US gal/min]. At higher pump
speeds or higher charge flows the charge pressure will rise
over the rated setting.
3.
Rotate the adjusting screw clockwise to increase the set-
ting; counter clockwise to decrease it. Subtract the case
pressure reading to compute the actual charge pressure.
NOTE:
Pressure change per turn is dependant on charge flow
entering pump.
4.
While holding the adjusting screw, torque locknut to 17
Nm [13 lb.ft.].
5.
When you achieve the desired charge pressure setting,
remove the gauges and plug the ports.