Toro Groundsmaster 4500-D Series Service Manual page 153

Procedure for Traction Circuit Relief Pressure Test (continued)
Groundsmaster ® 4500-D/4700-D
19245SL Rev A
g308279
1. Forward relief valve
2. Reverse relief valve
3. Piston (traction) pump
4. Reverse traction port
3. Locate traction circuit test fitting for function to be checked (forward or
reverse):
A. For testing the forward traction circuit, a test fitting is located on a
hydraulic tube on the right side of the machine below the hydraulic oil
filter (Figure 62).
B. For testing the reverse traction circuit, a test fitting needs to be temporarily
installed in the piston (traction) pump reverse traction port on left side of
pump (Figure 63). Thoroughly clean side of pump around plug to prevent
system contamination. Remove plug from pump reverse traction port and
then install straight fitting, 90º fitting and diagnostic test fitting into pump
port (see Special Tools (page 2–16)
4. Connect a 700 bar (10,000 PSI) pressure gauge to traction circuit test fitting
for function to be checked (forward or reverse).
5. Start the engine and increase engine speed to high idle speed. Make sure
that traction speed is in the HI (transport) range. Release parking brake.
6. While sitting on seat, apply brakes fully and slowly depress the traction pedal
in the appropriate direction (forward or reverse).While pushing traction pedal,
identify pressure reading on gauge as relief valve opens:
GAUGE READING TO BE:
Forward: 283 to 317 bar (4100 to 4600 PSI)
Reverse: 328 to 362 bar (4750 to 5250 PSI)
7. Release traction pedal and stop engine. Record test results.
8. If traction pressure is too low, makes sure that bypass valve on traction pump
is fully seated and then inspect traction pump relief valve in piston (traction)
pump (Figure 63). Clean or replace valves as necessary. These cartridge
type valves are factory set and are not adjustable. If relief valves are in good
condition, piston (traction) pump, wheel motors and/or rear axle motor should
be suspected of wear and inefficiency.
Figure 63
5. Straight fitting
6. 90º fitting
7. Diagnostic test fitting
for fitting part numbers).
Page 5–51 Hydraulic System: Testing