Terex Evoquip Bison 120, Operation Manual, Page: 182 / 224

10 Troubleshooting
Operations Manual
Bison 120
20-07-2018
Page 10-8
Revision 2.0
Fault Cause Correct Measure
One track not
operating or operating
slower than the other
Different sizes of motors fitted to
track
Check that the same size of
motors have been fitted to both
tracks
Oil flow going to the tracks not
flowing evenly and allowing a
motor to turn quicker in one
direction. This will cause the
Machine to ‘crab’ in one direction.
Check oil flow to tracks, swap
hoses between both tracks to
eliminate final drive mechanical
issues. Replace pump/ solenoid
as necessary
Brake pressure regulator valve
jammed due to debris will stop
the motor turning on one side
Swap the pressure regulator from
the opposite block to see if the
problem is in the brake valve. If
the valves continue to jam then
the oil in the hydraulic system is
not being filtered to the required
level of cleanliness.
Motor Fault
Swap over the motors on the two
tracks. If the fault is in the motor,
replace with a new motor
Faulty brake
Remove the motor and look
into the gearbox for heat
discolouration and/or fragments
of brake disc. If the fault is in the
brakes the complete gearbox will
have to be replaced.
Faulty brake piston seals
Remove the motor. If there is
hydraulic oil in the gearbox
entrance then the seals are
damaged. While it may be
possible to replace these seals
on-site we strongly recommended
that a replacement gearbox is
fitted and an overhaul of the
damaged gearbox be carried out
off-site.
Track group running
off Sprocket and / or
idler
Track group too loose Check track tension
Excessive misalignment
Check alignment of Sprocket Idler
and track rollers
Excessive component wear Check wear limits
Twisted track frame Check track frame