Service Manual

Groundsmaster 4100--D/4110--D Hydraulic SystemPage 4 -- 41
Procedure for Traction Circuit Relief Pressure Test
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine under load for
approximately ten (10) minutes. Make sure the hydrau-
lic tank is full.
CAUTION
Movemachine toan openarea, away frompeople
and obstructions.
2. Drive machine to an open area, lower cutting deck,
turn the engine off and engage the parking brake.
CAUTION
Prevent personal injury and/or damage to equip-
ment. Read all WARNINGS, CAUTIONS and Pre-
cautions for Hydraulic Testing at the beginning
of this section.
3. Connect a 10,000 PSI (700 bar) pressure gauge to
traction circuit test port for function to be checked: for-
ward (Fig. 27) or reverse (Fig. 28).
4. After installing pressure gauge, start engine and run
at idle speed. Check for hydraulic leakage at pressure
gauge location and correct before proceeding with test.
5. Move throttle so engine is running at high idle speed
(2870 RPM). Make sure that Hi/Low speed switch is in
the Hi speed (2WD) position.
6. Siton seat,apply brakesfully and slowly depress the
traction pedal in the appropriate direction. While
pushing traction pedal, look at pressure reading on
gauge:
GAUGE READING TO BE:
Forward: 3750 to 4250 PSI (259 to 293 bar)
Reverse: 4750 to 5250 PSI (328 to 362 bar)
7. Release traction pedal and stop engine. Record test
results.
8. If traction relief pressure is too low, inspect traction
pump relief valves (Fig. 29). Clean or replace valves as
necessary. These cartridge type valves are factory set
and are not adjustable. If relief valves are in good condi-
tion, traction pump or wheel motors should be sus-
pected of wear and inefficiency.
NOTE: Seal leakage across pilot directional valves
PD1 and PD2 in 4WD manifold can cause low forward
tractionpressure with reverse pressure meetingspecifi-
cations.
9. When testing is completed, disconnect pressure
gauge from test port.
1. Forward traction port 2. LH front tire
Figure 27
1
2
1. Reverse traction port 2. RH front tire
Figure 28
1
2
1. Forward relief valve
2. Reverse relief valve
3. Traction pump
Figure 29
FRONT
RIGHT
1
2
3
Hydraulic
System