Service Manual

Groundsmaster 4300--D Hydraulic SystemPage 4 -- 35
5. Connecta5000PSI(350 bar) pressuregauge to test
port.
6. After installing pressure gauge, start engine and run
at idle speed. Check for any hydraulic leakage from test
connections and correct before proceeding with test.
7. Move throttle to full speed (3200 RPM).
8. Sit on seat, and with brakes applied, slowly depress
the traction pedal in the direction to be tested (forward
or reverse). While pushing traction pedal down, careful-
ly watch the pressure gauge needle. As the traction re-
lief valve lifts, the gauge needle will momentarily stop.
Traction system pressure as the relief valve opens
should be:
3625 PSI (250 bar) in both forward (R3) and re-
verse (R4)
NOTE: If traction pedal continues to be pressed after
the relief valve has opened, system pressure can in-
crease higher than relief pressure.
9. Release traction pedal, stop engine and record test
results.
NOTE: Forward (R3) and reverse (R4) relief valves are
identical. Relief valves can be switched in traction pump
to help in identifying a faulty relief valve.
10.If problem occurs in one direction only, interchange
the relief valves in the traction pump (Fig. 35) to see if
the problem changes to the other direction. Clean or re-
place valves as necessary. These cartridge type valves
are factory set, and are not adjustable. If pressure is in-
correct and relief valves are in good condition, traction
pumpand/orwheelmotors should besuspectedof wear
and inefficiency.
11.After testing is completed, make sure that engine is
stopped and then relieve hydraulic system pressure
(seeRelievingHydraulicSystemPressurein theGener-
alInformationsectionofthischapter).Removepressure
gauge from machine.
1. Lower hydraulic tube 2. Forward test port
Figure 33
1
2
1. AWD hydraulic manifold 2. Reverse test port
Figure 34
1
2
1. Piston (traction) pump
2. Reverse relief valve (R4)
3. Forward relief valve (R3)
Figure 35
2
3
1
FRONT
RIGHT
Hydraulic
System