24 MHD56037 - Edition 5
TROUBLESHOOTING
This section provides basic troubleshooting information. Determination of specific causes to problems are best identified by thorough
inspections performed by personnel instructed in safety, operation and maintenance of this equipment. The chart below provides a brief
guide to common winch symptoms, probable causes and remedies.
SYMPTOM CAUSE REMEDY
Winch will not operate. No air supply to winch. Check air supply line connections and hoses.
Winch is overloaded. Reduce load to within rated capacity.
Disc brake does not release. Pressurize disc brake release port and check for leakage. Replace brake
piston seals if leakage is found. Ensure air pressure at inlet to disc brake is
at least 50 psig (3.4 bar/340 kPa).
Shipping plugs may still be in
place.
Remove shipping plugs in valve and motor exhaust ports.
Drum brake does not release. Disengage manual drum brake, or refer to ‘Automatic Drum Brake
Adjustment’
on page 26.
Load continues to move when
winch is stopped.
Drum brake is slipping. Check drum brake adjustment on page 26 and brake band lining wear.
Winch is overloaded. Reduce load to within rated capacity.
Winch motor controls sticking. Check pendant/throttle levers spring return to normal (neutral) positions
when released.
Winch does not lift load or
does not lift rated capacity.
Motor may be damaged. Remove and disassemble motor as described in the “MAINTENANCE”
section
on page 30. Examine all parts and replace any that are worn or
damaged.
Insufficient air supply. Verify air supply pressure and volume at winch inlet meets requirements
listed in the “SPECIFICATIONS” section
on page 5. Clean air line filter.
Throttle or pendant lever
moves but winch does not
operate.
Motor may be damaged. Disassemble and clean motor and replace any broken or damaged parts.
Insufficient air supply. Ensure air pressure at winch inlet is at least 90 psig (6.3 bar/630 kPa) at
rated volume. Clean air line filter.
Air leak. Check hose and fitting connections. Inspect hose(s) for breaks. Tighten
fittings and repair or replace hoses as necessary.
Motor runs hot or makes
excessive noise during
operation.
Low oil level. Check oil level in motor. Add oil as required to obtain proper level.
Improper lubrication. Replace oil with type recommended in “LUBRICATION” section on
page 19. Set lubricator to provide 6 to 9 drops of oil per minute at
maximum winch operating capacity.
Water in oil. Drain and refill with recommended oil. Operate winch with no load
slowly, in both directions. If noise still exists or motor overheats
disassemble and repair motor.
Damaged or broken piston or
connecting rod.
Disassemble and repair motor.
Winch runs slow. Improper hose or fitting sizes. Check fittings, connections and hoses for correct size and length. Replace
parts that may cause restricted air flow. Inspect air line filter.
Motor may be damaged. Remove and disassemble motor as described in the “MAINTENANCE”
section
on page 30. Inspect all parts and replace all worn or damaged
parts.
Brake(s) not releasing. Refer to brakes in “MAINTENANCE” section on page 26.
Air lines freeze. Water in air supply. Install or drain air system moisture traps, moisture collecting air receivers
and compressor aftercoolers. After corrective action has been taken,
disconnect lines at winch inlet and purge with clean, dry air or nitrogen.
Throttle lever hard to actuate,
or lever does not spring return
to neutral.
Valve body sticking in
bushing.
Lubricate valve through grease fitting with recommended lubricant. Refer
to ‘Air Throttle’
on page 19 in “LUBRICATION” section.
Automatic Drum Brake:
Brake cylinder will not
release.
Drum brake out of adjustment. Adjust drum brake to maintain correct cylinder stroke.
Leaking cylinder seals. If air is noticed escaping from cylinder breather when attempting to
release brake, replace or repair cylinder.
Dirty filter in air supply. Clean or replace filter.
Faulty dump valve. Check dump valve exhaust port. Air should exhaust when control valve
handle is in neutral. If no air escapes, replace dump valve.