Sauer Danfoss 51 Series Service Manual page 26

Bent Axis Variable Displacement Motors
Start-Up Procedure and Maintenance (Continued)
Maintenance
Cleanliness
The reservoir breather air filter (if equipped) must be
kept clean. Clean the area around the filler cap before
opening the reservoir. The hydraulic fluid should be
filtered before it enters the reservoir.
Follow the guidelines presented in Sauer-Sundstrand
publication BLN-9887 or 697581 for required fluid
cleanliness levels during machine operation.
Recommended Fluids
Hydraulic fluids used with Sauer-Sundstrand prod-
ucts should be carefully selected with assistance
from a reputable supplier, following the guidelines
presented in Sauer-Sundstrand publication BLN-9887
or 697581.
Checking for Leaks
Check the system components for leakage at regular
intervals. Tighten any leaking connections while the
system is not under pressure. Replace any defective
seals and gaskets.
Check hydraulic hoses for damage or aging. When
installing replacements, be certain that the hoses are
clean and connected properly.
Checking the Fluid Level
Check the reservoir daily for proper fluid level, the
presence of water (noted by a cloudy or milky appear-
ance, or free water in bottom of reservoir), and rancid
fluid odor (indicating excessive heat).
26
Changing the Fluid and Filter
To insure optimum service life on Series 51 products,
regular maintenance of the fluid and filter must be
performed.
The fluid and filter must be changed per the vehicle/
machine manufacturer's recommendations. In the
absence of such recommendations, the following
intervals may be used:
• System with a sealed type reservoir - 2000 hrs.
• System with a breathing type reservoir - 500 hrs.
It may be necessary to change the fluid more fre-
quently if the fluid becomes contaminated with for-
eign matter (dirt, water, grease, etc.) or if the fluid has
been operating at temperature levels greater than the
maximum recommended. Never reuse fluid.
The filter should be changed when changing the fluid,
or whenever the filter indicator shows that it is neces-
sary to change the filter.
Series 51
30 - 4