Danfoss 20 Series - Neutral Difficult or Impossible to Find; System will Not Operate in Either Direction

Service Manual and
Axial Piston Pumps Series 20
Repair Instructions
L1003506 • Rev BA • Jun 2014 13
Neutral Difficult or
Impossible to Find
System will not Operate in
either Direction
Check control
linkage
Repair
or replace
Inspect control valve
(see page 15)
Replace
pump
Replace control valve
(see page 23)
OK OK
DefectiveDefective
Check fluid
level in
reservoir
Check control
linkage
Inspect motor
by-pass valve
(if used)
Repair
or replace
OK
Defective
OK
Fill to
propper level
to low
Repair
or replace
Defective
Check charge
pressure
(see page 14)
OK
Inspect
charge pump
(see page 14)
Inspect
inlet filter
Repair
or replace
(see page 21, 22)
Defective
Replace
Defective
Inspect charge
pressure
relief valve
(see page 14)
Repair
or replace
(see page 21, 22)
Clogged
Inspect purge
relief valve at motor
(see Series 20 Axial Piston
Motors, Service Manual
and Repair Instruction)
Repair or replace
the valve block
(see Series 20 Axial Piston
Motors, Service Manual
and Repair Instruction)
Defective
Replace
transmission
(pump + motor)
Inspect
control valve
(see page 15)
Replace
control valve
(see page 23)
Defective
Inspect motor
by-pass valve
(if used)
Repair
or replace
Defective
Check system
pressure
(see Series 20 Axial Piston
Motors, Service Manual
and Repair Instruction)
to low in
neutral and
forward or
reverse
to low in
forward or
reverse
to low in
neutral
OK
OKOK OK
OK OK OK
Troubleshooting