T415 Operation & Service Manual
76
Maintenance
30
Series 90
Toubleshooting
System Response is Sluggish
Check
Description
Action
1. Oil level in reservoir.
2. Multi-function valves’ pressure set-
tings.
3. Pump inlet vacuum.
4. Prime mover speed.
5. Charge and control pressures.
6. System internal leakage.
Insufficient hydraulic fluid will reduce
output pressure.
Incorrect pressure settings will affect
system reaction time.
High pump inlet vacuum will reduce
system pressure.
Low engine speed will reduce system
performance.
Incorrect charge or control pressures
will affect system performance.
Internal leakage will reduce system
pressure.
Fill reservoir to proper level.
Adjust or replace multi-function valves.
Measure charge inlet vacuum. If high
replace inlet filter.
Adjust engine speed.
Measure charge and control pressures
and correct if necessary.
Check for leakage in O-rings, gaskets,
and other fittings.
Excessive Noise and/or Vibration
Check
Description
Action
1. Oil in reservoir.
2. Air in system.
3. Pump inlet vacuum.
4. Shaft couplings.
5. Shaft alignment.
Insufficient hydraulic fluid will lead to
cavitation.
Air bubbles will lead to cavitation.
High inlet vacuum will create noise. A
dirty filter will increase the inlet vacuum.
A loose shaft coupling will cause exces-
sive noise.
Unaligned shafts will create excessive
frictional noise.
Fill reservoir to proper level.
Look for foam in reservoir. Check for
leaks on inlet side of system loop. After-
wards, let reservoir settle until bubbles
are gone. Run system at low speed to
move system fluid to reservoir. Repeat.
Inspect and replace filter as necessary.
Check for proper suction line size.
Replace loose shaft coupling in charge
pump or replace pump or motor.
Align shafts.
If the above actions do not remedy the problem
contact a SAUER-SUNDSTRAND Authorized Service Center.
If the above actions do not remedy the problem
contact a SAUER-SUNDSTRAND Authorized Service Center.