JLG TOUCAN 861 Service Manual page 71

V-6
Hydraulic circuit pollution
- Abrasive wear caused by abrasive
particles.
Abrasive wear results in a gradual reduction of the
power and speed of the hydraulic system.
Fine particles may enter the circuit:
• During reservoir filling (clean the area around the
filling neck before opening the cap. Use clean
containers and funnels during filling procedure).
• Through worn seals, particularly on dirty and poorly
maintained material.
• During maintenance procedures if components are
not capped after hydraulic lines disconnection.
Models
Toucan 861
Updated 04-06
REMOVAL - INSTALLATION
Bearing wear
(dull area)
Wear on pinion pressure
plates (dull area)
Wear on gear track
(dull area)
- Abrasive wear caused by metallic particles.
Metal particle wear results in a fairly sudden
degradation of the performances of the pump. Metal
particles result generally from worn components or
from an abnormal wear of the hydraulic circuit : the
component must be identified and replaced. All the
hydraulic components must be removed and cleaned.
The hydraulic circuit must be drained out and flushed
and the filters replaced.
Cavitation
Track grooved on suction side =
overpressure
- Aeration or cavitation.
Cavitation and aeration act alike in the system.
Aeration occurs when air mixes with the oil. Air may
enter the system through a small suction leak or by
agitation of the oil in the reservoir. Agitation occurs
when the oil returns to the reservoir above the oil
surface. This may occurs when the oil level is too
low. Cavitation is the formation and collapse of vapour
bubbles in the oil. This usually results from a restricted
pump suction. Cavitation occurs more readily when
the oil is cold.
Aeration and cavitation erode and pit the pressure
plates and pump housing.
A pump which is either cavitating or operating on
aerated fluid is usually noisy and the system operates
in a spongy or jerky manner.
If erosion on the suction side of the pump is evident on
the gear tracks, the cause is either air bubbles in the
oil or a restricted suction.
V-6
Bearing wear
(grooves)
Wear on pinion
pressure plates
(grooves)
Wear on gearing
track (grooves)
71