Section IV. HYDRAULIC SYSTEM MAINTENANCE
This section contains general support maintenance procedures
for hydraulic pump and hydraulic reservoir.
Hydraulic Pump Maintenance . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Hydraulic Reservoir Maintenance
4-8. HYDRAULIC PUMP MAINTENANCE
This task covers disassembly, cleaning, inspection, and reassembly of hydraulic
pump. It also includes a short theory of operation.
THEORY OF OPERATION
Drive and driven gears turn in gear housing as shown; there is little clearance be-
tween gears and gear housing. Oil comes into area between gear teeth as gear teeth
move out of mesh on inlet side of hydraulic pump. As gears turn, oil is taken around
edge of gear housing. As gear teeth move into mesh again, oil is pushed out of out-
let side of hydraulic pump. Oil from outlet side of hydraulic pump pushes thrust
plates against sides of gears to prevent oil in outlet side from leaking to inlet
side of hydraulic pump; thrust plates are located on both sides of each gear set.
TOOLS: No. 1 Common Organizational Maintenance Tool Kit
Torque wrench, 3/4 inch drive
Socket wrench set, 3/4 inch drive
Slip joint pliers
Hand hammer, 16 ounces
Mechanical puller kit
Automotive Mechanics Tool Kit
Socket wrench set, 1/2 inch drive
Drive pin punch, 1/8 inch point
Micrometer, zero to 5 inches
MATERIALS/PARTS: Cleaning solvent P-D-680 (Appendix C, item 2)
Paper labels (Appendix C, item 3)
Lubricating oil (Appendix C, item 15)
Oil-soluble grease (Appendix C, item 26)
Retaining compound (Appendix C, item 33)
Seal kit (FSCM 13829 PN 391-1802-165)
PRELIMINARY PROCEDURE: Hydraulic pump removed (page 3-612).