Reference
( 1 ) Basic Hydraulic Function Checks
Action:
Do the following checks. Record details or repair obvious problems before proceeding to the hydraulic diagnostics.
Ask operator:
– How is machine performing?
– When does it malfunction?
– In what application?
Check maintenance records for:
– Correct service intervals
– Unusual, frequent or similar features
Check for:
– Disconnected, broken or binding operating linkage and wiring
– Kinked or dented oil lines
– Other mechanical failures
Check hydraulic oil condition:
– Oil reservoir level low?
Possible causes:
– Improper service intervals
– External leaks
Is oil milky or dirty?
Possible causes:
– Water in oil (milky)
– Filter failure (dirty)
Is oil discolored or burned odor? (overheated oil)
Possible causes:
– Kinked pipes
– Crushed hoses
– Plugged oil cooler
– Wrong oil viscosity
– Internal leaks
– Mechanical failure
Check for external oil leaks, with engine stopped and again with engine running. Review safety precautions.
IMPORTANT:
With engine running, if sound of hydraulic system seems to be under load or at high pressure, STOP ENGINE. Return to diagnosis in progress.
Cycle all hydraulic control levers, pedals and switches while running at slow idle.
Possible causes:
– Broken pipes, hoses or loose connections
– Leaking O-rings
– Cracked housing
Check for internal oil leaks with engine at slow idle:
– Listen for unusual noises in oil lines, passages, and control valves as hydraulic and power train functions are operated.
– Check for hot oil lines and passages.
– At slow idle, feel return lines and passages for excessive heat due to internal oil leaks.
– Turn steering full right and full left.
– Apply brakes.
– Move SCV lever forward and rearward (without cylinders). Repeat check with cylinder in each SCV coupler.
– Operate hitch with only an implement quick coupler installed using the position control lever.
Result:
YES: Go to next check.
NO: Return to diagnosis in progress.
