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Bobcat 220 HYDRAULIC SYSTEM TROUBLESHOOTING

Bobcat 220 TROUBLESHOOTING  THE  COMMON  CIRCUIT

PROBLEM CAUSE
No  operation  at  all Hydraulic  oil  level  low.
Hydraulic  pump  defective.
Main  relief valve presssure setting

incorrect

Hydraulic  pump  drive  coupling

damaged

Hydraulic  power  insufficient  or

speed  too  slow

Main  relief  valve  pressure  setting

incorrect.

Engine  output  reduced.
Hydraulic  oil  level  or  viscosity

incorrect.

Hydraulic  pump  volume  low.
Control  valve  defective.
Oil  temperature  too  high Hydraulic  oil  viscosity  incorrect.
Main  relief  valve  pressure
Relief valve  excessively  activated.
Ambient  air  temperature  too  high
Oil cooler or radiator fins plugged.
Hydraulic  oil  level  low.

 

PROBLEIVI CAUSE
Cylinder  inoperable Control  console(s)  raised
Control  console  lockout  switch.
Joystick  manifold   solenoid   valve

defective.

Joystick   manifold    solenoid    coil

defective.

Joystick      manifold      pressure

reducing  valve  defective.

Joystick internal leakage excessive.
Main  relief  valve  pressure  to  low.
Work  port  relief  valve  pressure  to

low.

Cylinder internal leakage excessive.
Lever  linkage  misadjusted.
Loose  fittings  or  broken  hoses.
Cylinder Force insufficient or speed

too  slow

Lever  linkage  misadjusted.
Main  relief  valve  pressure  to  low.
Work  port  relief  pressure to  low.
Cylinder internal leakage excessive.
Control    valve    internal    leakage

excessive.

Joystick  manifold   solenoid   valve

defective.

Joystick      manifold      pressure

reducing  valve  defective.

Joystick internal leakage excessive.
Cylinder  drift  excessive Cylinder internal leakage excessive.
Control    valve    internal    leakage

excessive.

Work port relief valve pressure low.
Work port relief valve seals leaking.

 

PROBLEM CAUSE
No  Swing  performance Control  console(s)  raised
Control  console  lockout  switch

defective.

Swing motor relief valves pressure

to  low.

Main  relief  valve  pressure  to  low.
Swing  motor  drain  excessive.
Swing  motor  gear  defective.
Joystick internal leakage excessive.
Joystick  manifold   solenoid   valve

defective.

Joystick    manifold    solenoid    coil

defective.

Joystick      manifold      pressure

reducing  valve  defective.

Swing  lock  pin  engaged.
Swing  force  or  speed  slow Swing  motor  relief  valve  pressure

to  low.

Control    valve    internal    leakage

excessive.

Joystick internal leakage excessive.
Swing    motor    internal    leakage

excessive.

Swing  motor  gears  defective.
Main  relief  valve  set  to  low.
Blocked  or restricted  line to swing

motor.

Control  valve  load  check  plug  not

functioning.

Pump  flow  low.
Swing  over  run  excessive Swing    motor    internal    leakage

excessive.

Swing  motor  relief  valves  set  to

low.

Control  valve  spool  sticking.
Joystick  spool  sticking.
PROBLEM CAUSE
Travel  system  inoperable Lever  linkage  misadjusted.
Control  valve  spool  sticking.
Swivel  joint  defective.
Travel    motor    internal    leakage

excessive.

Travel motor counter balance spool

sticking.

Travel  motor  gears  defective.
Main  relief  valve  pressure  to  low.
No  pump  pressure.
Track  tension  to  tight.
Travel  motor.
Travel  power  and  speed  slow Lever  linkage  misadjusted.
Control    valve    internal    leakage

excessive.

Swivel    joint    internal    leakage

excessive.

Travel    motor    internal    leakage

excessive.

Travel motor counterbalance spool

sticking.

Main  relief  valve  pressure  to  low.
Track  tension  to  tight.
Low  pump  pressure.
PROBLEM CAUSE
Machine  not  running  straight Pump  output  unequal.
Lever  linkage  misadjusted.
Swivel    joint    internal    leakage

excessive.

Travel    motor    internal    leakage

unequal.

Control    valve    internal    leakage

unequal.

Main  relief  valves  pressure  set  to

low.

Travel motor counter balance spool

sticking.

Track tension  unequal.
Machine  will  not  hold  on  slope  or

while  digging

Track motor counter balance valve

leakage  excessive.

Hose  damaged.
Blade  drops  while  machine  is

moving

Cylinder internal leakage excessive.
Control    valve    internal    leakage

excessive.

Swivel  joint  internal  leakage  from

travel  motor  pressure  circuit  into

blade  cylinder  circuit.

 

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