16-21. BOOM HOIST CYLINDER REPAIR
This Task Covers:
Tools and Special Tools
Compound, Sealing (Item 42, Appendix B)
Shop Equipment, Automotive Maintenance,
Oil, Lubricating, Transmission/Hydraulic
Common No. 2 Less Power
(Item 30, Appendix B)
(Item 17, Appendix D)
Solvent, Drycleaning P-D-680
Wrench Set, Spanner (Item 26, Appendix D)
(Item 52, Appendix B)
Packing, Preformed (7)
Boom hoist cylinder removed
Container, 5 gal (19 l) capacity
Use a vise with soft jaws to secure
boom hoist cylinder in a horizontal
position for disassembly.
Hydraulic oil, under pressure, can
remain within cylinder after
disconnecting hydraulic hoses. To
avoid severe personal injury, slowly
loosen counterbalance valve and
allow pressure to escape before
removing valve entirely.
Relieve pressure in cylinder by
slowly removing counterbalance
valve (l) from cylinder tube (2).
Drain residual oil through valve
holes into a suitable container.
Remove back-up rings (3 and 4), two
back-up rings (5), and three
preformed packings (6, 7, and 8) from
each counterbalance valve (l).
Discard preformed packings.
Disassemble boom hoist cylinder parts (9 through 24).