Check Wheel Hub Locknuts; Check Wheel Lug Nuts; Thread Locking Adhesives; Dielectric Grease - Exmark NAVIGATOR NV640KC Operator's Manual

Maintenance
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 section.
Exmark Premium Hydro Oil is recommended.
Refer to the chart for an acceptable alternative:
Hydro Oil
Exmark Premium Hydro
Oil (Preferred)
Mobil 1 15W50
5. Raise the rear of machine up and support with
jack stands (or equivalent support) just high
enough to allow drive wheels to turn freely.
6. Start engine and move throttle control ahead to
full throttle position. Move the speed control
levers to the full speed and run for several
minutes. Shut down machine and recheck oil
level.
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.

Check Wheel Hub Locknuts

Service Interval: After the first 100 hours
Every 500 hours thereafter
Torque to 210–250 ft-lb (285–339 N-m).

Check Wheel Lug Nuts

Service Interval: After the first 100 hours
Change Interval
500 Hours
250 Hours
Torque to 90–95 ft-lb (122–129 N-m) cross pattern.
Fuel Tank — Mounting
Hardware Specifications
Service Interval: As required
When installing the nuts on the fuel tank studs, fully
tighten the nyloc nut and back off 1/2 turn. This
allows for normal fuel tank expansion and contraction
with changes in temperature and fuel levels.

Thread Locking Adhesives

Thread locking adhesives such as "Loctite 242"
or "Fel-Pro, Pro-Lock Nut Type" are used on the
following fasteners:
• Pump drive sheave set screws.
• Square head setscrews on Hydro pump control
arms.
• Sheave retaining bolt in the end of engine
crankshaft, blower shaft and jackshaft.
• Caster wheel spacer nuts.
• Fuel tank bulkhead fitting nuts.
Adhesives such as "Loctite RC/609 or RC/680" or
"Fel-Pro Pro-Lock Retaining I or Retaining II" are
used on the following:
Fuel tank studs, where studs are inserted into tank.

Dielectric Grease

Dielectric grease is used on all blade type electrical
connections to prevent corrosion and loss of contact.
Dielectric grease should not be applied to sealed
connectors.
30
Every 500 hours thereafter