Unic URW295CUR, Workshop Manual

Page: 91 / 155

17 . 3 Cause of Troubles and Measures to be Taken ( Hoist winch )
Problems Possible cause Measures to be taken
Pressure does not rise.
Pump is faulty.
(Pressure does not rise at idling speed.)
(Total pressure required for operation is
insuicient.)
Replace.
Relief set of control valve is faulty.
(Pressure rises but not enough.)
Adjust or replace.
O-ring and other parts of relief valve of
control valve are faulty.
(Adjusting bolt of relief valve is tight-
ened but unable to control pressure.)
Replace parts or replace relief
ass' y with new one.
Hoist motor is faulty.
(Quantity of drain is larger than the spec-
ified.)
Replace.
Pressure rises but hoisting
up impossible.
Drum or internal mechanism of reduction
gear is faulty.
Overhaul reduction gear.
Inspect the drum
Pressure rises but lowering
is impossible.
Brake shoe is over-tightened.
Drum or reduction gear is defective.
Adjust tightening of brake
shoe.
Overhaul reduction gear.
Check drum.
Unable to maintain suspend-
ed load.
Brake shoe is faulty.
Pawl is faulty. Replace brake shoe.
Replace pawl.
When lowering, hunting
occurs.
Brake shoe is faulty.
Over-tightening of brake shoe.
Internal mechanism of reduction gear is
faulty.
Inspect brake shoe and check
quantity of oil.
Adjust tightening of nut.
Disassemble reduction gear.
When hoisting up, clattering
sound is heard.
Spring pressing the pawl against slide
plate is faulty.
Bushing the part of fitting pawl is worn
out.
Replace spring.
Replace bushing.
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