Alamo MACHETE Product Service Manual page 150

POSSIBLE FAILURE / CAUSE & SOLUTION
Cylinder Excessive Drift:
CAUSE:
Leakage Past Control Valve Spool?
SOLUTION:
If excessive Cylinder Drift is confirmed and the Cylinder and Work Port Relief Valves
have been eliminated, The possibility is the Control Valve Spool itself. If clearance
between the Control valve Spool and Body are causing the drift, the Only Solution is
to replace the Valve Section. Keep in mind that the cause for excess clearance must
be found and corrected. Frequently the cause is pre-mature wear from abrasive
material (Contamination) in the Oil. If this is not corrected failure will re-occur.
CAUSE:
Abrasive Contamination In Oil?
SOLUTION:
Abrasive Contaminants (Dirt, Iron Particles, Clutch Disc Material etc.) in the Oil Sump
/ System is a major contributor to all of the above internal leakage problems. It is
especially likely if the Positioning Hydraulics are using Oil from the Tractor Hydraulic
System. If the Tractor Hydraulic System is not properly maintained, Materials from
Gears, Clutch Disc and Etc. can enter the Control Valve and Cylinders causing
excessive Pre-mature Wear. If Abrasive material Wear is found the complete system
Should be flushed and cleaned. On Some Later Models an additional Filter System
has been added as additional Filtering of Tractor Hydraulic Oil. But even this add on
Filter, if not maintained, will run through the Filter Bypass and contaminate System.
KEEP FILTERS CLEAN and/or Replace on a good Maintenance Schedule.
CAUSE:
Electrical Short Circuit?
SOLUTION:
Electrical short causing controls to emit electrical current even though controller
is in neutral position. Check all wire connections and try to determine where electrical
short is, Repair or replace as needed. Usually this type of problem will allow drift to
be rapid unless Short is through Joystick controller, There should be no electrical
current when Valve and Joystick are in centered (neutral) position
Cylinder Leaks At Fittings:
CAUSE:
Loose or Wrong Fittings?
SOLUTION:
Make sure correct Fittings are installed and are torque to correct specification. Boss
Fittings may have damaged O-Ring, Check and repair as required.
CAUSE:
Port Cracked at Fitting?
SOLUTION:
Repair or Replace Cylinder and/or Fitting. This type failure is more common on
Cylinders with Pipe Fittings than the ones with O-Ring Boss Fittings. The reason is
because the Pipe Thread is tapered and can be over tightened and the tapered
thread acts as a wedge. Don't over tighten any fittings, Don't use Teflon tape at all,
if using a Semi Liquid Pipe Thread Sealer Don't put excessive amount on fitting and
Never put sealer into ID of Port, It will get into system and contaminate it.
CAUSE:
Deformed or Damaged Fitting? (JIC)
SOLUTION:
Replace damaged Fittings and/or Hose, Over tightening of JIC Fittings can deform
the Flares on the Fitting and create leaks. See Torque Specification for proper
Torque Values.
Machete (Service Manual) 04/04
© 2004 Alamo Group Inc.
(Continued)
150