Groundsmaster 4500--D/4700--DHydraulic System Page 4 -- 86
IMPORTANT: A case drain exists in the piston (trac-
tion) pump and a suction port is near the input shaft
of the gear pump (Fig. 70). Before the gear pump is
installed to the piston pump, make sure that plugs
placed in both of these ports are removed. Failure to
remove plugs will cause excessive pressure in the
piston pu mp and damage seals. Also, before secur-
ing gear pump to piston pump, fill piston pump
housing with clean hydraulic oil through case drain
hole.
4. Remove plugs that were placed in piston p ump case
drain andgear pump suction port. Fill piston pump hous-
ing with new hydraulic oil through case drain hole.
5. Install gear pump to piston pump (see Gear Pump in
this section).
6. Using labels placed during pump removal, connect
wire harness connectors to the two (2) solenoid coils on
left side of piston (traction) pump.
7. Fill piston (traction) pump housing with new hydraul-
ic oil through the case drain (90
o
barbed fitting) at thetop
of the pump (Fig. 71). This will ensure that internal pump
components have adequate lubrication during initial op-
eration.
8. Remove plugs and caps from disconnected hydrau-
lic lines and fittings of the pump assembly. Install hy-
draulic lines to correct location on gear and piston
pumps (see Hydraulic Hose and Tube Installation in the
General Information section of this chapter).
9. Fill hydraulic reservoir w ith correct oil.
10.Install new hydraulic filter and fill hydraulic reservoir
with correct oil.
IMPORTANT: Refer to Traction Circuit Component
Failure in the General Information section of this
chapter for information regarding the importance of
removing contamination from the traction circuit.
11.Prime hydraulic pumps (see Priming Hydraulic
Pumps in this section).
12.Properly fill hydraulic system (see Charge Hydraulic
System in this section).
13.Stop engine and check for hydraulic oil leaks. Check
hydraulic reservoir oil level and adjust if necessary.
1. Piston (traction) pump
2. Gear pump
3. Piston pump case drain
Figure 71
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3
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