lUbRICaTION
47
Purging Procedures
Due to the effects air has on efficiency in hydrostatic
drive applications, it is critical to purge the system.
These purge procedures should be implemented
any time a hydrostatic system has been opened to
facilitate maintenance or any additional oil has been
added to the system.
Resulting symptoms in hydrostatic systems may be:
Noisy operation.
•
Lack of power or drive after short term operation.
•
High operation temperature and excessive
•
expansion of oil.
Shortened component life.
•
Before starting, make sure the oil tank is at the proper
oil level. If not, fill to the specifications outlined above.
The following procedures are best performed with the
vehicle drive wheels off the ground, then repeated
under normal operating conditions.
Disengage the brake if activated.
1.
With the bypass valve open and the engine
2.
running at fast idle, slowly move the directional
control in both forward and reverse directions (5
or 6 times). As air is purged from the unit, the oil
level will drop.
With the bypass valve closed and the engine
3.
running, slowly move the directional control
in both forward and reverse directions (5 to
6 times). Check the oil level and add oil as
required after stopping the engine.
It may be necessary to repeat Steps 2 and 3
4.
until all the air is completely purged from the
system. When the hydraulic drive operates
at normal noise levels and moves smoothly
forward and reverse at normal speeds, the
hydraulic drive is considered purged.
After the vehicle has been used two times, the
5.
oil level should be checked while the oil is cold
and adjusted accordingly.
