SkyTrak 6036 Operation Manual - Manual (Page 99)

Page 93 6036/6036T
After the boom has been retracted fully, proceed as
follows:
1. If the line failure is in the boom hoist line, proceed
as follows. Using two people to perform the
procedure will make lowering the boom much
easier.
a. Remove the blocking that is supporting the
boom.
b. At the base end of each hoist cylinder, locate the
counterbalance valve cartridges (Figure 63).
c. Loosen the retainer nut (Figure 63) and
control the rate of boom lowering by simulta-
neously turning the adjusting screw on each
cartridge into the cartridge very slowly
(clockwise). Hydraulic oil from inside the
hoist cylinders will escape through the fault in
the line.
2. If the line failure is in the boom lowering line,
proceed as follows:
a. At the base end of each hoist cylinder, locate the
counterbalance valve cartridges (Figure 63).
b. Loosen the retainer nut (Figure 63) on each
cartridge and turn the adjusting screws in
(clockwise) until they bottom out. This will
render the counterbalance valves inoperative.
c. Reposition the capscrew into the spool shift
collar of the boom hoist/lower spool (right
spool) on the main control valve (Figure 64).
d. Remove the blocking that is supporting the
boom.
e. Clear the area around the vehicle of all
personnel.
f. Move the capscrew backward to shift the
boom hoist/lower spool. This will allow you to
lower the boom in a slow uniform manner.
IMPORTANT: This procedure is to be used in emergency
situations only. By turning the counterbalance cartridge
adjusting screws to lower the boom, the pressure settings
of the cartridge have been altered. DO NOT attempt to
reset these cartridges. Remove and replace all three
cartridges with new parts. Failure to replace these
cartridges with new parts will result in erratic (extreme
bouncing) lowering action, which may cause damage to
other components.