MTS Series 505 SilentFlo Hydraulic Power Unit Model 505-180 - Manual (Page 101)

Replacing the Hydraulic Fluid
Model 505.60 - 505.180 SilentFlo™ HPU Maintenance 101
8. Remove the hose and valve assembly.
Replacing the Hydraulic Fluid
Replace the hydraulic fluid in the HPU reservoir whenever you have determined
that the hydraulic fluid is no longer suitable for use.
Recommended
equipment
• A transfer pump with a 10 micron filter (such as the Model 590.01 Fluid
Transfer Pump) with 915 mm (36 inch) suction tube.
• Synasol or a similar cleaning solvent
• Lint-free cloths or manufactured lint-free rags
• A hydraulic fluid sampling kit (MTS part number 055-589-601)
• A new filter
Appearance of Hydraulic Fluid Sample
Fluid Properties Problem What to Do
Dark colored fluid Indicates chemical breakdown or
the hydraulic fluid has been allowed
to rise above the maximum
recommended temperature (severe
overheating) Analyze the fluid and replace as
required by the analysis.
If the cause was overheating, flush the
entire system to remove varnish or
residue. Consult your MTS Field
Service Engineer to determine if
changes or adjustments to your
hydraulic system are required.
Burnt odor Indicates chemical breakdown or
the hydraulic fluid has been allowed
to rise above the maximum
recommended temperature (severe
overheating) Analyze the fluid and replace as
required by the analysis.
If the cause was overheating, flush the
entire system to remove varnish or
residue. Consult your MTS Field
Service Engineer to determine if
changes or adjustments to your
hydraulic system are required.
Opaque fluid Indicates chemical breakdown Replace the fluid
Milky appearance Indicates water is present in the
fluid Check the heat exchanger for damage.
Look for other water sources if the
water does not appear to be coming
from the heat exchanger.
Identify and correct the source of the
water leakage and replace the fluid if
necessary.
Sediment at the bottom of
the sample container (after
sample has stood
overnight) Indicates collapsed, ruptured, or
clogged filter(s) Analyze the fluid and replace all filter
elements.
Clean the fluid or replace it as required
by the analysis.