Toro Sand Pro 5040 Service Manual page 53

Procedure for Traction Relief Valve (R3) Pressure
Test:
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine for approximately 10
minutes.
2. Park machine on a level surface with the attachment
removed. Make sure engine is off and that the parking
brake is applied.
3. Read and follow Precautions for Hydraulic Testing.
4. Make sure that traction pedal is adjusted to the neu-
tral position (see Operator's Manual).
IMPORTANT: Make sure to thoroughly clean around
all hydraulic connections that will be disassembled.
5. Determine the hydrostat charge pressure by per-
forming the Charge Relief Valve (R2) Pressure Test.
6. Remove plug from forward traction port on bottom of
hydrostat (Fig. 20). Install pressure gauge to test port.
7. After installing pressure gauge, start engine and run
at low idle speed. Check for hydraulic leakage and cor-
rect before proceeding with test.
8. Operate engine at full speed (3400 RPM).
CAUTION
Use extreme caution when taking gauge read-
ings. The front wheel will be turning.
9. Sit in the operator seat, make sure that the parking
brake is applied and slowly push traction pedal in the
forward direction. Depress traction pedal to between
1/3 and 1/2 of pedal travel. Engine speed should de-
crease to approximately 2800 RPM as pedal is de-
pressed.
IMPORTANT: DO NOT hold system at relief for more
than a few seconds.
IMPORTANT: DO NOT allow pressure to exceed
4000 PSI (275.8 bar) during testing.
10.While depressing traction pedal, watch the pressure
gauge and record pressure when the traction circuit re-
lief valve opens.
Sand Pro & Infield Pro 3040/5040
11. Pressure gauge reading should be at least 3200 PSI
(220.7 bar) higher than charge pressure. Record test
results.
Example: Consider a machine that has a charge pres-
sure of 240 PSI (16.6 bar). The traction relief pressure
for this machine should be at least 3440 PSI (237.3 bar).
12.Release traction pedal and turn engine off.
NOTE: If the relief pressure cannot be obtained and en-
gine speed drops excessively (below 2800 RPM) as the
traction pedal is depressed, engine performance should
be evaluated (see Chapter 3 – Gasoline Engine).
13.If traction relief pressure is incorrect, inspect traction
relief valve (R3) in hydrostat (see the Sauer–Danfoss
(Sundstrand) 15 Series Service Manual at the end of this
chapter). Clean or replace relief valve as needed. If re-
lief valve is in good condition, acceleration valves and
charge check valve in hydrostat should be inspected as
well. A worn or damaged hydrostat could be considered
if relief, check and acceleration valves are in good condi-
tion.
14.If traction relief pressure is correct and a traction cir-
cuit problem exists, check traction pump (P1) flow (see
Traction Pump (P1) Flow Test in this section) and wheel
motor efficiency (see Wheel Motor Efficiency Test in this
section).
15.When testing is complete, remove hydraulic pres-
sure gauge from machine and install plug into hydrostat
port.
16.Make sure hydraulic tank is full (see Operator's
Manual).
1
3
1. Hydrostat (from below)
2. Forward traction port
Page 4 – 25
2
Figure 20
3. Traction rod
Hydraulic System