18-2. HYDRAULIC SYSTEM SERVICE
This Task Covers:
a. Purging air from piston pump.
b. Purging-air from tandem gear pump.
Tools and Special Tools
Oil, Lubricating, Transmission/Hydraulic (Item 22,
Tool Kit, General Mechanic's: Automotive
(Item 18, Appendix F)
Rags (Item 25, Appendix C)
Cap and Plug Set (Item 3, Appendix F)
Tags (Item 38, Appendix C)
Container, 1 gal (3.8 l) capacity
Transmission cover removed (Para 16-5)
a. Purging Air from Piston Pump.
· Hydraulic oil in system can be under pressures over 3000 psi (20685 kPa) with engine OFF.
ALWAYS relieve pressure in hydraulic hoses before attempting to remove any component in
hydraulic system. With engine OFF, starter switch in RUN position, and attachment on ground,
move control levers through all operating positions several times to relieve hydraulic pressure.
Relieve pressure in hydraulic oil tank by loosening filler cap very slowly. Failure to follow these
precautions could result in serious injury or death to personnel.
· At operating temperatures, hydraulic oil is hot and under pressure. Hot oil can cause injury to
personnel. Allow hydraulic oil to cool before disconnecting any hydraulic hoses.
· Wipe area clean around all hydraulic connections to be opened during removal and disassembly.
Cap oil hoses and plug holes. Contamination of hydraulic system could result in equipment failure.
· To prevent internal damage to piston pump ensure pump housing is filled with oil before beginning
· Remove caps and plugs as hoses are installed. Wipe all sealing surfaces on hydraulic components
and hoses clean and dry. Apply light coating of clean hydraulic oil to all seals as installed.
· Piston pump supplies hydraulic pressure to the attachment cylinder assembly, carriage tilt cylinder,
and fork sideshift cylinders.