PUMPS
SUB-SECTION 4B
4. Remove the large snap ring and pull the driveshaft and
REASSEMBLY. Reassemble the pump, with a presassem-
bearing from the body. Drive the shaft seal and wiper out
bled pumping cartridge, as follows:
from the shaft of the body. If it necessary to remove
the shaft bearing, first remove the small snap ring. Then
1. Clamp the body in a vise or place it on blocks as at
press the shaft out of the bearing, while supporting the
disassembly.
bearing inner race.
5. Remove the O-ring, and backup rings from the pressure
These are left hand rotation pumps. Check the rota-
plate. Remove the fillister head screws and lift off the wear
tion of the new cartridge before installing it in the
plate. Note the position of the am ring, rotor, and vanes to
pump, The direction of rotation arrow should point
assure correct reassembly. Separate the cam ring, rotor,
in a counterclockwise direction when the cartridge is
vanes, locating pins, and pressure plate.
viewed from the shaft end.
2. Install the O-ring and back-up ring on the pressure plate
INSPECTION AND REPAIR. Inspect and repair the fol-
hub. Lay the body O-ring in the body groove, and install
lowing items:
the large back-up ring and O-ring on the cartridge. Carefully
install the cartridge in the body so one of the chamfers on
1. Discard the shaft seal and all O-rings and back-up rings.
the cam ring will align with the inlet port when the inlet
Use new gasket kit for reassembly. Wash the metal parts
housing is installed.
in clean mineral solvent, blow them dry with filtered, de-
hydrated air, and place them on a clean surface for inspec-
3. Place the inlet housing over the cartridge so the locating
tion.
pins are properly engaged, and the inlet is in the correct
position with respect to the body outlet. Install the four
2. Check the wearing surfaces of the cartridge parts for
screws and torque them to the values shown in Figure 4B-5.
scoring and excessive wear. Remove light score marks by
lapping. Lubriting, Moly-Koteing or equivalent is desir-
4. Install the cover end cartridge, being certain the pins
able after lapping to prevent seizure during start-up. Re-
engage the inlet housing. Place the large back-up ring and
place any heavily scored or badly worn parts.
O-ring on the pressure plate.
3. Inspect the vanes and inserts for burrs, wear, and exces-
5. Install the small O-ring and back-up ring on the pressure
sive play in the rotor slots. Replace the rotor if the slots are
plate hub. Install the cover O-ring in its groove. Install the
worn.
cover and screws. Tighten the screws to the torque values
shown in Figure 4B-5.
4. Rotate the bearing while applying pressure to check for
wear, looseness and pitted or cracked races.
OVERHAUL
5. Inspect the seal and bushing mating surfaces on the shaft
DISASSEMBLY. Use the following procedure in conjunc-
for scoring or wear. Replace the shaft if marks cannot be
tion with Figure 4B-5 to completely disassemble the pump:
removed by light polishing.
1. Support the pump on blocks clamp the body in a vise
as shown in Figure 4B-6. If a vise is used, use protective
jaws to avoid damage to the body and its machined sur-
REASSEMBLY. Use the following procedure to reassemble
faces.
the pump:
2. Mark the body, inlet housing, and cover for correct re-
NOTE
assembly. Remove the four cover screws and lift the cover
off me pump. Remove the cover O-ring (see Figure 4B-7).
Coat all parts except seals and back-up rings with
Pull and/or pry out the cover end cartridge as shown in
clean hydraulic fluid to facilitate reassembly, and to
provide initial lubrication. Use small amounts of
petroleum jelly to hold the O-rings in place during
3. Next, remove the four screws attaching the inlet housing
reassembly.
to the body. Lift off the inlet housing (see Figure 4B-9)
and remove the body O-ring. Turn the driveshaft to free the
1. Place the pressure plate on blocks as shown in Figure
cartridge and pull the cartridge from the body.
4B-10. Place the rotor on the pressure plate with the arrow
4B-6
