Service Manual

HYDRAULIC SYSTEMS
4 - 2 Mid-Mount Z Service Manual
Description
The hydraulic system consists of a fluid reservoir
supplying 2 Hydro-Gear BDP-10L hydrostatic pumps
through a spin-on filter. The pumps are controlled by
adjustable wrap around handles through a bellcrank
and linkage to the pump control lever. These pumps
also feature a bypass valve which may be opened to
allow the unit to be pushed by hand.
Fluid from the main hydraulic passages of each pump
are routed through high pressure rubber hoses and
fittings to Ross MB15 Motors located at each wheel.
Refer to the appropriate Hydro-Gear or Ross service
manual for pump and motor service procedures.
General Hydraulic Assembly Guidelines
The following guidelines must be followed to in order to
maintain a leak free unit:
1. Extreme care must be taken to prevent any dirt/
debris from entering the hydraulic system. Always
cover open lines and fitting with clean plugs or
aluminum foil.
2. Do not pull plastic plugs until just prior to
assembly. Make sure that no paint flakes fall into
the open port. Do not remove plastic plugs with a
sharp knife.
3. Ensure that the fittings are clean, free from nicks,
and corrosion. The insides of all hoses and lines
must be clean.
4. Always apply clean oil to all O-rings prior to
assembly.
5. Once a hose or steel line is started, it is important
to continue to tighten until finger tight. This is
done to ensure the O-ring stays in its groove.
6. A back-up wrench must be used any time a hose
is tightened. This prevents the hose from turning
and damaging or dislodging the O-ring.
7. All hydraulic fittings must be torqued to
specifications (see Torque Recommendations For
Hydraulic Fittings chart on page 1 - 3.
Replacing the Pump Drive Belt
Check pump drive belt for wear after every 50 hours of
operation.
1. Using a suitable pry bar, release the spring
tension on the idler pulley and remove the drive
belt from the pump pulley (Figure 59).
Figure 59
1023-012
2. Install new belt around engine and hydro pump
pulleys (Figure 60).
Figure 60
3. Pull spring loaded idler down and align below
traction belt. Release pressure on spring loaded
idler (Figure 60).
Pump Belt Routing