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REV. 3 - 03/10
Section III: Maintenance
Page 86
TROUBLESHOOTING
BOOM SLEW FUNCTIONING IMPROPERLY
Problem
Cause
Solution
Boom will not
a. Slew locking pin engaged
a. Disengage locking pin
rotate
b. Swing brake control valve b. Inspect: remove blockage
clogged with foreign
material
c. Faulty swing brake control c. Replace
valve
Slew locking pin will
a. No air pressure
a. Turn truck on
not engage
b. Insufficient air pressure
b. Allow truck to run
c. Defective pressure switch c. Inspect and replace
d. Leaking air line
d. Inspect and replace
e. Defective air cylinder
e. Inspect and replace
f. Jammed locking pin
f. Inspect and replace
g. Ice buildup on pin and/or
g. Thaw
air cylinder
Slew locking pin will
a. No air pressure
a. Turn truck on
not disengage
b. Insufficient air pressure
b. Allow truck to run
c. Defective pressure switch c. Inspect and replace
d. Leaking air line
d. Inspect and replace
e. Defective air cylinder
e. Inspect and replace
f. Jammed locking pin
f. Inspect and replace
g. Ice buildup on pin and/or
g. Thaw
air cylinder
Slew lock indicator
a. Limit switch out of
a. Inspect: adjust
light stays illuminated
adjustment
b. Ice buildup on limit switch
b. Thaw
c. Defective limit switch
c. Inspect and replace
d. Locking pin is not
d. Disengage locking pin
disengaged
e. Electrical circuit wiring
e. Check/repair electrical wiring
problem
circuit
Slew lock indicator
a. Limit switch out of
a. Inspect: adjust
light will not illuminate
adjustment
b. Ice buildup on limit switch
b. Thaw
c. Defective limit switch
c. Inspect and replace
d. Locking pin is not
d. Engage locking pin
engaged
e. Electrical circuit wiring
e. Check/repair electrical wiring
problem
circuit
f. Defective controls
f. Check, repair or replace
compartment door
activation switch
g. Indicator light burned out
g. Repair or replace
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