the hand-pump, slowly apply pressure to observe if
there is any movement of the suspended load. If the
load begins to lower, there may be a gear train fail-
ure in the hoist. The load may be lowered by control-
ling the pressure to the ABS port; more pressure
releases faster, less pressure releases slower.
Lower the load
VERY SLOWLY
to minimize the heat
generated by the slipping ABS brake discs.
3. If no movement is observed, apply 800 PSI (5500
kPa) to the ABS release port and keep the hand-
pump valve closed to hold the pressure in the ABS
and keep the ABS released.
4. Move to the motor end of the hoist. Close the brake
isolation needle valve and remove the cap/plug from
the static brake release port tee.
5. Install the hand-pump equipped with the -4 JIC
adapters to the static brake release port tee.
6. Install the stand-pipe described previously to the
lowering port of the motor. Fill the stand pipe with
hydraulic oil and have a helper stationed by the
stand-pipe with additional oil. Remove the hose from
the hoisting port on the brake valve to make certain
oil is not running through the motor and out a brake
valve that is stuck open. If oil is running through the
brake valve, tap the main spool retainer cap with a
hammer to dislodge the stuck spool. If this does not
close the brake valve, remove the spool spring
retainer cap and tap the spool back into the closed
position with a hammer and punch. Install the spool
and spring retainer caps and proceed with the emer-
gency load lowering. If the main spool was stuck in
the open position, the brake valve
MUST
be
replaced following the emergency lowering.
7.
SLOWLY
apply pressure with the hand-pump to the
brake release port. The load will begin to lower at
approximately 250-400 PSI (1700-2750 kPa). As the
load begins to lower the helper must make certain
the stand pipe is kept full of oil. If a chattering noise
is heard while the load is coming down, the brake
discs are dragging. Increase the pressure from the
hand-pump slightly to further release the brake.
DO
NOT
exceed 1500 PSI (10,350 kPa).
The stand-pipe must be kept full of oil. Attempting to
lower a load with no oil in the motor or with a brake
valve stuck open will cause the load to free-fall,
which could result in property damage, injury to per-
sonnel or death.
Do not touch the hydraulic motor or brake housing
while lowering a load. They may become hot and
cause burns.
The hoist
MUST
be removed from service following
an actual emergency load lowering procedure. The
hoist MUST be disassembled and all parts thorough-
ly inspected for damage. All wear items
MUST
be
replaced along with new brake components, motor
and brake valve. The hoist
MUST
be load tested
before returning to service. Failure to repair the hoist
following an emergency load lowering may result in
loss of load control due to damaged components.
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