Alamo MACHETE Product Service Manual page 148

POSSIBLE FAILURE / CAUSE & SOLUTION
Cylinder Boom Positioning:
CAUSE:
SOLUTION:
CAUSE:
SOLUTION:
Control Valve Spool or Spools Sticking
CAUSE:
SOLUTION:
CAUSE:
SOLUTION:
CAUSE:
SOLUTION:
Machete (Service Manual) 04/04
© 2004 Alamo Group Inc.
Cyl. Continue to move after Joy Stick released.
Boom Moves on its Own (Electronic Joystick).
Joystick does Not return to Neutral.
Defective or Damaged Joy Stick Controller?
There are very few replaceable Parts in Joy Stick Controller, See the Repair
Section for Testing and repairing the Joystick. DO NOT Replace Joystick till all
Test have been performed to pin down the problem area. There are a number
of test to locate problem area that can be used, these are listed through out
sections of the repair Manual as well as some listed in the Operators Manual.
Oil Contaminated?
If the Filters are Not Maintained properly on the Tractor Hydraulic System, Fine
contaminates can get into the Solenoid valves, this prevents them from seating
Properly. This can result in Boom Circuits moving without input from the
Joystick Controller. When Filters get full, It causes the Bypass valve on the Filter
to Open and allow unfiltered Oil to go throughout the System. Once this is
allowed to happen even though the Filters are later changed, it is no guarantee
that the malfunction will not re-occur because the contamination could be any
where in the system waiting to break free and travel on through the system.
Later Models (Machete) had an add on filter added which has a lower Micron
Rating than Tractor Filter, This was added to keep Contamination from Tractor
System from going through the Boom System, Both Tractor and add on Boom
Filter will have to be changed an a regular maintance schedule, See Operators
manual.
Control Valve Bolted to Mounting Plate Incorrectly?
Loosen bolts and re-tighten 1 turn at a time using a criss-cross pattern. The
Valve Body can be placed in a bind if the mounting bolts are tightened un-evenly.
This can cause the Spool to stick in the bore or cause the Valve to leak internaly.
Contamination in Valve Spool?
Find Contamination source and correct it, Clean Valve, Change Filters, Re-
place Oil (if required to remove contamination), Re-Assemble and Test.
Faulty Valve Spool or Section?
Replace Valve Section, If the valve Section is defective, The Malfunction will
most likely occur immediately after being placed in service. If the Unit has been
operating for sometime, the problem is most likely to be a failure not a defective
part there fore more checking maybe needed to determine why the Valve Spool
failed.
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