Page 52
472H Potato Harvester Owner Operator’s Manual
Periodically air may become trapped in the hydraulic sys-
tem. After working with the hydraulic system, “bleed” air
from the system. Where hydraulic oil will not compress, air
will compress. Therefore if any air pockets or bubbles are in
the cylinder it will become “spongy” and will not hold its
position. Cycle cylinders completely several times to purge
air. If air still exists in the cylinders, bleed the cylinders as
follows:
1.
Begin this operation by first loosening the clevis end
(“B”) fitting about one full turn. Cover this fitting with a
towel or rag to prevent the spray from hitting you or the
machine.
2.
Activate the appropriate switch to retract the cylinder
“A”. Release switch to its neutral position when fluid
starts to spray from the loose fitting. Tighten this fitting
and retract the cylinder fully by activating the appropri-
ate switch.
3.
Loosen the plunger end (“A”) fitting and repeat the pro-
cedure as used on the retraction only extend the cylin-
der this time.
4.
After completing the system bleeding, check the fluid
reservoirs for oil level.
4.4.4 BLEEDING THE SYSTEM
WARNING
Hydraulic fluid under pressure can pierce the skin, caus-
ing injury or death. Do not expose bare skin to pressur-
ized hydraulic fluid. Use eye protection and appropri-
ate protective clothing to prevent injury. If skin is punc-
tured, seek medical help immediately.
Fig. #66 Bleeding the system
4.4 MAINTENANCE
After the system is bled, adjust the flow control of the
tractor’s remote hydraulic outlet to the appropriate flow rate.
The electro-hydraulic valve is supplied all by the remote trac-
tor outlet. Excessive flow will potientially overload the trac-
tor with heated hydraulic oil that could damage the tractor’s
hydraulic system.
