Toro Groundsmaster 7210, Service Manual

Page: 72 / 342

Traction Circuit (Closed Loop) Component Failure
The traction system of the Groundsmaster 7210 machine consists of 2 identical
and independent closed loop traction circuits. If a component failure occurs
in 1 of these traction circuits (e.g., wheel motor or transmission piston pump),
unwanted material and contamination from the damaged component will
circulate throughout the traction circuit. This contamination can damage other
components in the circuit, so remove the contamination to prevent additional
component failure.
If a component failure occurs in 1 of these traction circuits, disassemble the
entire traction circuit, drain the hydraulic fluid, and clean the traction circuit
(transmission piston pump, hydraulic hoses, and wheel motor) to ensure that you
remove all contamination from it. Operating the machine with contaminants in
the traction circuit could cause additional damage to components of the traction
circuit.
An alternative procedure to remove contamination from the traction circuit is to
temporarily install a high-pressure hydraulic-fluid filter into the circuit; refer to
Special Tools (page 4–23) . Use a high-pressure hydraulic-fluid filter when you
connect the hydraulic test gauges in order to test the traction circuit components
or after you replace a failed traction circuit component (e.g., wheel motor or
transmission piston pump). Using a high-pressure hydraulic-fluid filter will
remove contaminates from the hydraulic fluid in the traction circuit, thereby
preventing additional component damage.
After you have installed the high-pressure hydraulic-fluid filter in the traction
circuit, raise and support the machine with jack stands and operate the traction
circuit to allow the hydraulic fluid to the circuit. With the machine raised off the
ground, the traction circuit will have maximum fluid flow at minimum pressure
to minimize damage from any remaining contamination. This filter removes
contaminants from the closed loop traction circuit during the circuit operation.
When you are certain that the filter has removed the contaminates from the
hydraulic fluid of the traction circuit, remove the filter.
IMPORTANT
When you operate the traction system with the additional
high-pressure filter, ensure that the flow is always directed through
the filter before it enters into a replaced component (e.g., do not
move the traction levers to move the machine in the reverse
direction if you installed the filter in the traction circuit for moving
the machine in the forward direction). If hydraulic fluid flows in the
opposite direction through the high-pressure hydraulic-fluid filter,
contamination from the filter will again circulate through the traction
circuit.
Hydraulic System: General Information Page 4–12 Groundsmaster 7210
16222SL Rev C