SUB-SECTION 4B
PUMPS
3. Carefully install the pump on the pump drive, and install
is installed. Tap the shaft and bearing gently into the body
the mounting screws. Care should be exercised in tightening
and install the large snap ring.
the mounting screws to prevent misalignment.
4. Reconnect the suction and outlet lines. Then turn the
These are right hand rotation pumps. Check the rota-
suction line valve to the open position.
tion of the cartridge before installing it in the pump.
The direction of rotation arrow should point in a
5. Engage the pump drive and start the engine. Allow the
clockwise direction when the cartridge is viewed from
engine to run at idle speed, with no load applied to the
the shaft end.
hydraulic system to prime the pump. Then run the engine
at moderate speed and load for a short period of time.
6. Install the O-ring and back-up ring on the pressure plate
Check the reservoir oil level and add oil if required.
hub. Lay the body O-ring in the body groove, and install
the large back-up ring and O-ring on the cartridge. Carefully
install the cartridge in the body so one of the chamfers on
the cam ring will align with the inlet port when the inlet
housing is installed.
SINGLE PUMP (41Z104)
GENERAL
7. Place the inlet housing over the cartridge so the locating
pins are properly engaged and the inlet housing is in the
Single hydraulic pump 41Z104 is used to develop fluid flow
correct position with respect to the body outlet. Install the
for the operation of the auxiliary winch.
four screws and torque them to the values shown in Figure
4B-27.
The pump illustrated in Figure 4B-36 is representative of the
8. Install the cover end cartridge, being certain the pins
single pump. The pump consists principally of an inlet
engage the housing and that cartridge rotation is correct.
cover, outlet body, driveshaft and pumping cartridge. The
principal components of the cartridge are en elliptical cam
Place the large back-up ring and O-ring on the pressure
plate.
ring, a slotted rotor splined to the driveshaft, a pressure
plate, wear plate, and ten vanes and inserts fitted to the
rotor slots.
9. Install the small O-ring and back-up ring on the pressure
plate hub. Install the cover O-ring in its groove. Install the
cover and screws, and tighten the screws to the torque
values shown in Figure 4B-27.
PRINCIPLES OF OPERATION
Fluid enters the pumping cartridge through the inlet port
end is discharged through the pressure plate to the outlet
INSTALLATION
port. The action of the pump cartridge is illustrated in
Figure 4B-37.
Care must be exercised when installing a new or overhauled
pump on the pump drive to prevent misalignment, which
The rotor is driven within the cam ring by the driveshaft,
can lead to premature pump failure. Install a new or over-
which is coupled to the pump drive. As the rotor turns,
hauled pump on the pump drive as follows:
centrifugal force on the vanes, aided by under-vane pressure
fed from the outlet port, causes them to follow the ellip-
1. Check the mounting flange on the pump drive, the pilot
tical inner surface of the cam ring.
diameter on the pump, the splined coupling, and the
splined driveshaft for burrs or imperfections that would
Prevent the pump from seating properly on the pump drive.
Radial movement of the vanes and turning of the rotor
Carefully remove any imperfections by lapping.
cause the chamber volume between the vanes to increase as
the vanes pass the inlet section of the cam ring. This results
2. Apply a light coating of grease to the pilot diameter and
in a low pressure condition which allows atmospheric pres-
drivesheft splines. Position the gasket on the pump.
sure to force fluid into the chambers.
4B-21
