Alamo MACHETE Product Service Manual page 163

POSSIBLE FAILURE / CAUSE & SOLUTION
Hydraulic System Overheating:
CAUSE:
Restrictions? Just as indicated, an unintentional obstruction to normal Oil Flow
through the circuit.
SOLUTION:
Check for an unwanted increase in pressure, The obstruction would be down stream
from the Pressure increase, so you would want to check pressure going back toward
pressure inlet. As Oil passes through the obstruction it causes Heat increase, a check
of temperatures will generally be near restriction, a heat sensing gun works well for
this. Some Examples of Restrictions are:
The number of possibilities is numerous, Do not forget when checking especially for
kinks in hoses it may be required to run the cylinders through their complete range of
movement to check them. Know what repair work or modifications were performed.
CAUSE:
Wrong Type Valve being Used For Tractor? (Tractor Hydraulics Only)
SOLUTION:
Determine type of Control Valve for Tractor, Is tractor a Fixed Displacement (Open
Center) System or a Load Sense (Closed Center) System. Make Sure the Valve that
is installed is the correct one for the Type Tractor Hydraulics be used. If the Wrong
System is Used it will cause a Heating problem.
CAUSE:
Spool Valve Stuck In Open or Partially Open Position?
SOLUTION:
Repair or Replace Valve components as needed.
CAUSE:
Relief Valve Set to Low? (Load Sense / Closed Center Only)
SOLUTION:
Relief Valve for Mower Positioning Control Valve must be set higher than Tractor Relief
Valve, Otherwise the Oil will bypass continuously and overheat rapidly.
CAUSE:
Leakage?
SOLUTION:
This type Leakage is Internal, an External Leak will not cause Heating unless it causes
enough Oil loss to effect the Oils cooling. Another type leakage would be Air entering
the system on the suction side, This may not leak externally when system is engaged
because it would be a suction. Some internal leakage is always present because of
tolerance in the components, Valve, Pump, Motor and other components. But usually
this is compensated for in the design of the system and components. Internal leakage
will normally increase with wear and age on the system components. Heating from
normal internal leakage is usually not severe or noticeable until it reaches advanced
stages. It usually occurs gradually and is accompanied by a gradual loss of power.
Test System for leakage by running Pressure and flow Test, Rebuild or Replace as
required.
Machete (Service Manual) 04/04
© 2004 Alamo Group Inc.
Kinked, Mashed or Internally Broken Hoses.
Obstruction by foreign materials in lines.
Plugged Filter or Wrong Filters installed
Open (Stuck) By Pass Valve
Wrong Size Hoses or fittings installed.
Repair work done and parts assembled wrong.
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