KB21 Service Manual Pub 09-14
94
Visual Test
slip on cover that prevent visual inspection of general condition of components. Look for any broken
components, missing components, loose components, oil leaks, damaged components. Look for any
thing that is obvious to cause a problem.
2. Replace any missing / broken components, tighten any loose components and repair any oil leaks
before beginning any further test.
Mechanical Control Valve
Operational Test
1.Visual test should have been done already, if not go back one page and perform visual test now.
Pump and/or valve covers should be removed.
the heads motor hydraulics pressure and the second section (smaller section) supplies the control
valve hydraulics pressure.
3. With tractor engine running operate each circuit, paying close attention to everything the unit does
or does not do.
4. The engine speed should drop slightly (the sound change) when the valve spool moves and the
pump come under a load, if the engine sound does not change when the circuit is activated, it is an
indication that there is no load being placed on pump.
5. Observe each movement of the cable controls throughout its complete range of movement. Check
the cylinder speeds; look for “jerky” operation, the cylinder should respond smoothly to the movement
of the control valve controls. Look for time delay between movement of controls and movement of
cylinders.
6. After checking each function, attempt to duplicate the malfunction described by operator, using the
information gathered in the operator interview. If you are not able to get machine to malfunction; see
if operator can get the machine to malfunction.
7. When the malfunction occurs, take note of all conditions that exist during the time of the
malfunction, some things to take note of are:
A. Engine speed or sound
B. Position of articulating members
C. Operating temperature
D. Length of time unit has been running
E. Position of control levers before and during malfunction
F. Position and condition of tractor
G. Any other condition you might notice.
8. Duplicate the conditions that existed when the malfunction occurred to determine if the malfunction
would occur every time that the same conditions exist. Try different combinations of conditions to
determine which conditions actually affect the malfunction and which ones just happened to be there
when the malfunction occurred.
80 - A. Mechanical Control Valve
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