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
Defective
Defective
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
OK
OK
OK
OK
OK
OK
Troubleshooting