Service Manual
Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607
• Rev AI • Sep 2013
22
Adjustment (continued)
LS Control
Warning
Escaping hydraulic fluid
under pressure can have
sufficient force to penetrate
your skin causing serious
injury and/or infection.
Relieve pressure in the system
before removing hoses,
fittings, gauges, or
components.
Unintended movement of the
machine or mechanism may
cause injury to the technician
or bystanders. To protect
against unintended
movement, secure the
machine or disable/
disconnect the mechanism
while servicing.
LS control adjustment
LS adjusting plug
0 - 300 bar [0 - 4351 psi]
9/16-28
34-68 N•m [25-50 lbf•ft]
Case drain port L1
0 - 300 bar [0 - 4351 psi]
9/16-28
34-68 N•m [25-50 lbf•ft]
Gauge port M1
0 - 300 bar [0 - 4351 psi]
9/16-28
34-68 N•m [25-50 lbf•ft]
LS set screw
0 - 300 bar [0 - 4351 psi]
9/16-28
7.5-10.8 N•m [5.5-8 lbf•ft]
P104 367E
LS/ remote PC signal port X
Caution
Contamination can damage
internal components and void
the manufacturer’s warranty.
Take precautions to ensure
system cleanliness when
removing and reinstalling
system lines.
The LS setting is indicated in the pump model code. Refer to the
Series 45 J Frame Open Circuit Axial
Piston Pumps Technical Information Manual,
520L0676
, for more information.
Before performing adjustments, read page 15,
Pressure measurement.
1. Install a pressure gauge in port M1 to measure system pressure. Install a pressure gauge in drain
port L1 or L2 to measure case pressure. Tee-in a gauge to the LS/remote PC signal line (port X).
C
2. Start the prime mover and allow fluid to reach normal operating temperature. Slowly operate a hydraulic
function that will demand approximately half flow from the pump, but keep system pressure below the
PC set point.
3. Loosen the LS set screw. While watching the pressure gauges, turn the LS adjusting plug until the
desired pressure differential between port M1 and port X is achieved
1
. Clockwise rotation increases
the setting, counterclockwise rotation will decrease it; approximate gain = 17 bar [250 psi] per turn.
4. While holding the position of the LS adjusting plug, torque the LS set screw to 7.5 - 10.8 N•m [5.5-8
lbf•ft].
5. Operate a hydraulic function to its full extension loading the pump at maximum pressure and zero
flow.
6. Loosen the PC set screw and turn the PC adjusting plug until the desired setting is indicated on the
pressure gauge at port M1
2
. Clockwise rotation increases pressure, counterclockwise rotation
decreases it; approximate gain = 42 bar [610 psi] per turn.
7. While holding the position of the PC adjusting plug, torque the PC set screw to 7.5 - 10.8 N•m [5.5-8
lbf•ft].
8. Stop the prime mover, remove the pressure gauges, and return the system to its normal operating
configuration.
1
The LS setting is a differential pressure. Subtract pilot pressure at port X from system pressure at port M1 to compute the
actual setting.
2
PC setting is referenced to case pressure. Subtract case pressure from system pressure to compute the actual setting.
If the pressure does not
increase, an external system
relief valve may require
adjustment. External system
relief valve must be set above
the PC setting for proper
operation.