The boom telescope cylinder has a 5.5 in. (13.9 cm)
fittings is 24 ft (7.3 m). The cylinder has a stroke of
bore. The cylinder is internally ported (rod ported).
21.6 ft (6.5 m) which gives the cylinder an overall
Oil from the telescope control valve is routed to the
extended length of 45.6 ft (13.9 m) from the end of
cylinder by external lines.
Foreign material is
the cylinder barrel to the center of the attachment
prevented from entering the cylinder during rod
fittings on the cylinder rod.
retraction by a wiper seal in the head. O-ring seals
prevent internal and external leakage.
The cylinder weights approximately 1,305 lbs (591.9
kg) dry and 1,380 lbs (625.9 kg) wet.
The retracted length of the telescope cylinder from
the end of the barrel to the center of the attachment
For Removal and Installation procedures, refer to BOOM MAINTENANCE
in Section 10.
When removing seals and rings, avoid
scratching grooved and gland surfaces.
Any maintenance requiring disassembly
replacement of all cylinder seals and O-
Aligning discarded seals and rings in the
order of disassembly will facilitate
installation of new items.
Using a spanner wrench, unscrew the cylinder
head, refer to Figure 2-8-26.
Remove the hydrolock piston seal to gain
access to the setscrew securing the piston to the
Do not use air pressure to remove the
Remove the setscrew and unscrew the piston
cylinder rod assembly. Use only a
from the cylinder rod.
source of controlled hydraulic oil
pressure, if the rod is hard to remove.
Remove the remaining hydrolock seal and
guide lock ring from the outside of the piston and the
O-ring and two backup rings from the inside of the
Exercise extreme care when handling or
setting down the cylinder rod. Do not
Remove the spacer from the rod and remove
damage the chrome surface.
the wear ring from the spacer.
Remove the cylinder rod assembly from the
Remove the cylinder head from the rod.
cylinder barrel and cover the barrel to avoid