National Crane 1-21-2019 Control # 104-07 5-11
1400A SERVICE MANUAL HOIST
TROUBLESHOOTING
FIGURE 5-9
12-4
12-1
12-2
12-3
12-1
Metering Hole
Problem Cause Solution
Hoist does not hold
load
Excessive back pressure in the system.
Check the system for restrictions and reduce the
back pressure.
Brake discs are worn out. Replace brake discs.
Hoist clutch is slipping.
Inspect the clutch and driver for wear and replace
worn parts.
The hoist does not
raise the load it should.
Relief valve setting may be too low to
allow proper lifting.
Increase relief valve pressure setting.
Load being lifted may be more than the
hoist's rating.
Reduce the load or re-rig to increase mechanical
advantage.
The hoist does not
lower the load.
The brake valve was improperly hooked
up after being disconnected.
Check plumbing and connect lines properly.
The cartridge in the brake valve may
have a plugged metering hole.
Remove the cartridge and clean it if necessary.
Oil leaks from the vent
on the motor side of the
hoist.
The motor shaft seal may have failed.
Replace this seal and reduce back pressure if that
caused the shaft seal to fail.
Brake piston seals may have failed. Service the brake section and replace worn parts.
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r
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