TM 5-3805-290-23-1
THEORY OF OPERATION - CONTINUED
0003 00
HYDRAULIC SYSTEM - CONTINUED
f.
These conditions could cause oil cooler bypass valve to divert oil around hydraulic oil cooler:
(1)
Cold hydraulic oil
(2)
Restriction in a hydraulic oil line
(3)
Restriction in hydraulic oil cooler
4.
Piston Pumps.
a.
Pumps are located on left side of machine under cab.
b.
Piston pump supplies oil to pilot system and steering system.
c.
Piston pump supplies oil to implements.
5.
Piston Pump Pilot and Steering.
a.
Pilot system piston pump and steering system piston pump has variable displacement, load sensing, compensation
for pressure, and compensation for flow. This piston type pump has variable flow and pressure dependent on sys-
tem demands sensed by pressure and flow compensator valves.
b.
When engine is OFF, there is no load sensing signal to pressure and flow compensator valve. A margin spring
pushes a flow compensator spool completely right. Any pressure behind actuator piston is vented to case drain
across flow compensator spool.
c.
When there is no pressure behind actuator piston, bias spring is able to hold swashplate at maximum angle.
d.
When engine is started, drive shaft starts to rotate. Oil flows into piston bore from pump inlet. Oil is forced out of
pump outlet and into system as cylinder barrel assembly rotates.
0003 00-136
