Figure 68. Control stand hydraulic compensators, removal and installation.
sure to open the bleed valve after the pressure is
upward toward the top row of compensators. When
applied and close the valve before the lever reaches the
bleeding air from the system, always start with the
end of travel or is released. If this caution is not
lowest unit and work upward.
observed, air will the sucked into the system through the
b. Attach the bleeder hose (fig. 69)
to the bleed
valve and use a clean jar or can t o catch the hydraulic
d. Check the level of the hydraulic fluid in the
fluid. Bleed the air from each of the hydraulic cylinders
reservoir and keep the reservoir filled at all times. This
on the machine, beginning with the lowest cylinders first
will prevent air from entering the supply line at the
and working toward the cylinders mounted at the highest
bottom of reservoir.
point. Keep the end of the bleeder hose at the bottom
of the can or jar used to collect the hydraulic fluid
removed from the bleeder valves. This wiII prevent air
from entering the bleeder hose and re-entering the
system. Manual operation of the controls will be
required to expel the air from the system.
a. Removal. Remove the compensator as shown
c. Work each of the controls slowly and note the
action on the machine. If any of the controls still feel
b. Cleaning and Inspection.
spongy, it may be necessary to remove the hydraulic
(1) Clean all parts in an approved cleaning
cylinder from the hydraulic cylinder assembly (fig. 70).
solvent and dry thoroughly.
Hold the hydraulic cylinder in the position shown, then
(2) Inspect for cracks, breaks, leaks and other
rock the cylinder back and forth to insure that all trapped
air is allowed to escape. Slight pressure may be applied
to the operating lever or pedal during this operation. Be