Manitowoc Published 11-22-17, Control # 257-02 2-19
MLC300 SERVICE/MAINTENANCE MANUAL HYDRAULIC SYSTEM
Inspecting and Replacing Hydraulic Hoses
Periodic Inspection
Visually inspect all hydraulic hose assemblies every month
or at 200 hours of service life for the following:
• Leaks at hose fittings or in the hose
• Damaged, cut, or abraded cover
• Exposed reinforcement
• Kinked, crushed, flattened, or twisted hose
• Hard, stiff, heat-cracked, or charred hose
• Blistered, soft, degraded, or loose cover
• Cracked, damaged, or badly corroded fittings
• Fitting slippage on the hose
• Other signs of significant deterioration
If any of these conditions exist, evaluate the hose
assemblies for correction or replacement.
At the same service interval, visually inspect all other
hydraulic components and valves for the following:
• Leaking ports
• Leaking valve sections or manifolds and valves installed
into cylinders or onto motors
• Damaged or missing hose clamps, guards, or shields
• Excessive dirt and debris around hose assemblies
If any of these conditions exist, address them appropriately.
Periodic Replacement
See Table 2-3 for the following.
Hydraulic hose assemblies operating in Zone C should be
replaced after 8,000 hours of service life.
Hydraulic hose assemblies operating in Zones A and B with
high ambient temperatures and high-duty circuits could see
hose service life reduced by 40 to 50%. High-duty circuits
can include, but are not limited to hoist(s), boom lift, swing,
travel, pump suction and discharge to directional valves, and
directional valve return to reservoir. Replace hoses
operating in Zones A and B after 4,000 to 5,000 hours of
service life.
Hydraulic hose assemblies operating in Zones D and E
should expect a degrade of mechanical properties. Long
term exposure to these cold temperatures will negatively
impact service life. Cold temperatures shorten hose life.
Therefore, frequent inspection is required.
Table 2-3. Climate Zone Classifications
CAUTION
Burn Hazard!
Oil in the hydraulic system may be under pressure and
extremely hot.
Before loosening any hydraulic fitting or hose, perform the
following:
• Wait until the hydraulic oil is cold.
• Vent the hydraulic tank and crack open fittings and
hoses slowly to allow pressure to vent.
Zone Description
A
Tropical Moist—All months average above 18°C
(65°F)
Latitude—15° to 25° N and S
B
Dry or Arid—Deficient precipitation most of the
year
Latitude—20° to 35° N and S
C
Moist Mid-Latitude—Temperate with mild winters
Latitude—30° to 50° N and S
D
Moist Mid-Latitude—Cold winters
Latitude—50° to 70° N and S
E
Polar—Extremely cold winters and summers
Latitude—60° to 75° N and S
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