Service Manual and
Axial Piston Pumps Series 20
Repair Instructions
L1003506
• Rev BA • Jun 2014
8
Preconditions for Trouble-
free Operation (continued)
First-time Operation
The charge pressure
measured at the charge pressure gauge connection port of the pump with the
adjusting lever in the neutral position should be approx. 15 bar [217.6 psi] at a pump input speed n =
1500 min
-1
(rpm).
The charge pressure measured at the charge pressure gauge connection port of the pump with the
adjusting lever engaged should be approx. 2 bar lower at a pump input speed n = 1500 min
-1
(rpm).
1. After installing the transmission and the corresponding pipeline connections, remove the plug
from the charge pressure gauge port of the variable displacement pump. Fit a gauge with a
measuring range up to 60 bar [870 psi] to this port.
The charge pressure gauge port has a straight 7/16-20 UNF-2 B SAE thread.
2. Disconnect the charge pump inlet line from the charge pump inlet connection pipe.
3. Fill the pump case and the motor case with the recommended oil through the drain port.
4. Fill the oil reservoir with fluid. As soon as oil emerges from the end of the discon nected charge
pump inlet line tighten the pipe connector (see
table to page 35
for the correct tightening torque)
and continue to fill the reservoir.
Only use oil reservoirs that are fitted with air filters.
5. Disconnect the control linkage from the control handle.
The pump must be in the zero position.
6. Allow the prime mover to turn for approx. 15 sec. by using the starter.
If the prime mover is an electric motor: Switch on and off again.
7. Then start the prime mover and allow the pump to turn at idling speed (approx. 750 min
-1
) for
approx. 5 minutes.
In the case of electric prime mover:
Allow to turn for approx.1 minute.
After initial fluctuations in pressure, the charge pressure should settle down to 10 bar [145 psi] or
12 bar [174 psi].
8. Check the pressure fluid level.
9. Raise the speed to approx. 1500 min
-1
(rpm). The gauge should now indicate a pres sure of approx.
15 bar [217.6 psi].
10. If the charge pressure falls to below 8 bar [116 psi], stop the prime mover, find the fault in
accordance with the trouble-shooting guide and take the appropriate remedial action.
Start-up procedure
