263920 R
2
Page 17
S
ervice
5.2
Cylinders
5.2-1
Main Lift Cylinder
Description
Left Hand Main Lift Cylinder
Right Hand Main Lift Cylinder
Figure 16a. Main Lift Cylinders.
The main lift cylinders (see Figure
16) are single stage displacement
type cylinders consisting of a shell
and a telescoping plunger/piston
assembly. During extension
hydraulic pressure is acting
against the plunger outer diameter
due to the internal porting through
the piston. The piston seals do not
affect cylinder extension. The
truck hoist control valve holds the
cylinders in place once extension
has stopped.
The shell is internally threaded at
the top end to hold the retainer.
The retainer seals provide a high-
pressure hydraulic seal against
the plunger. The retainer also
limits the upward stroke of the
plunger.
A piston is attached to the bottom
end of the plunger. The piston
seal provides a high-pressure
hydraulic seal against the shell
that engages the cushion valve
when the cylinder is fully lowered.
A hydraulic fuse/cushion valve is
located in the LH cylinder’s inlet
port. In case of a hose failure
between the lowering control valve
and the cylinders, the fuse limits
the lowering speed of the
cylinder.
TYPICAL ILLUSTRATION
Torque to 100 ft-lbs MIN
Install with LOCTITE 242
Torque to 50 ft-lbs MIN.
Piston
Hydraulic
Tube
Retainer
O-Ring
Fitting
Fitting
Spacer
(If required)
Piston Seal
Plug
Wear Ring
Retaining Ring
Rod Seal
Wiper
Rod End
Shell
Rod
Install with
Loctite 242
Torque to:
50 ft-lbs MIN.
MA2178.eps
External Fuse
O-Ring
