JLG 40H Service Manual - Manual (Page 118)

SECTION 3 - TROUBLESHOOTING
3-6
– JLG Lift – 3120240
Boom will swing in only one direction. Restricted or broken hydraulic line on fitting.
Control valve not functioning properly.
Foreign objects wedged between swing motor pin-
ion and swing gear.
Swing control lever not functioning.
Brake shuttle valve defective.
Clean, repair, or replace line or fitting.
Repair or replace valve.
Remove objects, check for damage, and repair or
replace component (s) as required.
Repair or replace swing control lever.
Replace shuttle valve.
Boom swings erratically in either
direction. Hydraulic system oil low.
Lack of lubricant on swing gear or speed reducer
pinion.
Swing motor not functioning properly.
Worn or broken teeth on swing gear or swing motor
pinion.
Swing brake not functioning properly.
Restrictor valves plugged.
Replenish oil as necessary.
Lubricate as required.
(See Lubrication Chart.)
Repair or replace swing control lever.
Replace gear(s) as required.
Repair or replace swing brake.
Clean or replace restrictor valve.
TROUBLE PROBABLE CAUSE REMEDY