SUB-SECTlON 6B
SWING REDUCERS
Table 6B-1 Swing Reducer Troubleshooting
PROBABLE CAUSE
TROUBLE
REMEDY
1. If this trouble occurs suddenly after
Remove the relief valve, disassemble
A. Swing reducer will not
working at maximum load, a particle of
and clean parts thoroughly in a suit-
deliver maximum torque.
dirt may be lodged under the relief valve,
able solvent. Reassemble and install
holding it partially open. If this is the
the relief valve.
cause, a considerable loss in speed may be
noticed as the load is increased.
2. The oil level in the reservoir may be
Check the oil level in the reservoir.
too low. The suction line may be re-
Check the suction line for damage,
stricted or have an air leak, causing cavita-
externally and internally. Replace the
tion at the pump inlet. This will cause the
suction line if necessary.
pump to make a whining sound.
3. After all the causes listed above have
Install a pressure gage in the gage port
been investigated and it is found that the
that is pressurized for clockwise rota-
swing reducer will stall at maximum pres-
tion, and apply a load to the swing
sure without developing the maximum
reducer. If the pressure is up to
load on the output shaft, the trouble may
maximum and the output torque is
be in the swing reducer.
less than that required to rotate the
upper at full speed, the trouble will
be in the swing reducer.
Disassemble the swing reducer ac-
cording to the disassembly instruc-
tions and inspect. Check that all gears
turn freely for forward rotation. If
the gears are found to be satisfactory,
inspect the hydraulic motor.
1. Same as Cause 1 of Trouble A.
Same as Cause 1 of Trouble A.
B. Considerable reduction in
speed.
2. Same as Cause 2 of Trouble A.
Same as Cause 2 of Trouble A.
3. If this trouble has increased gradually,
Remove and inspect the pump. If it
the pump or swing reducer motor may be
is satisfactory, remove and inspect the
swing reducer motor according to the
worn.
instructions for the motor.
1. Control valve may be restricted in it's
Check the travel of the control valve
C. Swing speed in one direc-
spool. The spool travel should be the
travel.
tion is slower than the
same in both directions.
other direction.
Check the flow of oil from the vent
2. Oil may be escaping past a damaged
line while the swing reducer is run at
O-ring in the brake cylinder.
full speed for 2 or 3 minutes with the
vent port plugged. If the flow con-
tinues, remove the motor. Dis-
assemble and inspect the O-rings in
the brake cylinder.
6B-3
