MTS Model 512-04 Hydraulic Power Unit - Manual (Page 31)

Model 512.04 Hydraulic Power Unit Maintenance 31
Changing the Hydraulic Fluid
As part of your regular HPU maintenance, change the hydraulic fluid every
2500 hours of operation or if fluid analysis indicates the fluid should be
changed. However, you must change it immediately if any of the following
is true:
• The fluid becomes very dark and has a strong burnt sugar smell
(indicates severe overheating).
• Particles appear in the sight glass (indicates the suction filter may need
cleaning).
• Fluid becomes milky (water in the fluid and a possible leaking heat
exchanger).
It’s a good idea to keep a small jar of new hydraulic fluid for comparison
purposes.
Recommended
equipment:
• A transfer pump with a 10–micron filter
• A 125 kg (250 lb) capacity hoist
• Synasol® or a similar cleaning solvent
• Lint-free cloths or manufactured rags
• A small drain that will fit underneath the drain plug
Procedure
See “Component Locations” on page 32 to identify the components called
out in the following procedure.
1. Prepare the HPU.
A. Press STOP to turn off the HPU.
B. Remove electrical power to the HPU (via the circuit breaker at the
power source or by unplugging the HPU).
C. Remove the filler cap’s strainer assembly.
2. Remove the hydraulic fluid.
A. Remove the transfer pump’s filter (you do not need to filter the
dirty hydraulic fluid when removing it).
B. Use the transfer pump to remove the old hydraulic fluid out of the
reservoir.
C. Remove the drain plug to drain any remaining fluid.