Exmark VH3615KA - Manual (Page 26)

- 21 -
e) 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.
f) Raise the rear of the machine up onto jack stands high enough to raise
the drive wheels off of the ground. Run machine to allow any other air to
be purged from the hydraulic system and recheck the oil level.
g) 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 7) may have lost
their “prime”. Refer to Section 5.1.10.
h) DO NOT change hydraulic system oil (except what can be drained when
changing filter) unless it is felt that oil has been contaminated. Changing
oil unnecessarily could damage the hydraulic system by introducing
contaminates into the system.
5.1.10 Hydraulic system air purge procedure.
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. (See Figure 7).
Air in other parts of the hydraulic system will be purged through normal
operation once the charge pump is “primed”.
a) Stop engine. Raise the rear of the machine up onto jack stands high
enough to raise the drive wheels off the ground.
b) Check oil level as stated in Section 5.1.8.
c) Start engine an move throttle control ahead to full throttle position. Move
the speed control lever to the middle speed position and place the drive
levers into the “drive” position.
If either drive wheel does not rotate, it is possible to assist the purging of
the charge pump by carefully rotating the tire in the forward direction.
NOTE: It is necessary to lightly touch the charge pump cap with your
hand to check the pump temperature. If the cap is too hot to touch, turn
off engine. The pumps may be damaged if the pump becomes too hot.
If either drive wheel still does not rotate continue with step (d).
d) Thoroughly clean the area around each of the charge pump housings.
FIG. 7
CHARGE PUMP LOCATION