Exmark Viking Hydro 920000 - Manual (Page 25)

Maintenance
Note: Use only Exmark Part No. 109-4180 for
Summer use above 32°F (0°C) or P/N 1-523541 for
Winter use below 32°F (0°C) (Refer to Transmission
section in Specifications for filter specifications).
1. Stop engine, wait for all moving parts to stop, and
remove key. Engage parking brake.
2. Carefully clean area around filter. It is important
that no dirt or contamination enter hydraulic
system.
3. Unscrew filter to remove and allow oil to drain
from reservoir.
Important: Before reinstalling new filter,
fill it with Exmark Premium Hydro Oil and
apply a thin coat of oil on the surface of the
rubber seal.
Turn filter clockwise until rubber seal contacts the
filter adapter, then tighten the filter an additional
2/3 to 3/4 turn.
4. Fill reservoir as stated in Check Hydraulic Oil
Level.
Exmark Premium Hydro Oil is recommended.
Refer to the chart for an acceptable alternative:
Hydro Oil Change Interval
Exmark Premium Hydro
Oil (Preferred) 500 Hours
Mobil 1 15W50 250 Hours
5. Loosen filter 1/2 turn and allow a small amount
of oil to leak from the oil filter (this allows air to
be purged from the oil filter and supply hose from
the hydraulic reservoir). Turn filter clockwise
until rubber seal contacts the filter adapter. Then
tighten the filter an additional 2/3 to 3/4 turn.
6. Raise the rear of machine up and support with
jack stands (or equivalent support) just high
enough to allow drive wheels to turn freely.
CAUTION
Raising the mower for service or maintenance
relying solely on mechanical or hydraulic
jacks could be dangerous. The mechanical or
hydraulic jacks may not be enough support
or may malfunction allowing the unit to fall,
which could cause injury.
Do Not rely solely on mechanical or hydraulic
jacks for support. Use adequate jack stands
or equivalent support.
7. If either drive wheel does not rotate, one or both
of the charge pumps (located on the top of the
main pump as shown in Figure 8) may have lost
their “prime”. Refer to Hydraulic System Air
Purge section.
Note: Do Not change hydraulic system oil (except
for what can be drained when changing filter), unless
it is felt the oil has been contaminated or been
extremely hot.
Changing oil unnecessarily could damage hydraulic
system by introducing contaminates into the system.
Hydraulic System Air Purge
Service Interval: As required
Air must be purged from the hydraulic system
when any hydraulic components, including oil
filter, are removed or any of the hydraulic lines are
disconnected.
The critical area for purging air from the hydraulic
system is between the oil reservoir and each
charge pump located on the top of each variable
displacement pump (Figure 8). Air in other parts of
the hydraulic system will be purged through normal
operation once the charge pump is “primed”.
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