Toro 04384 Service Manual page 63

Procedure for Charge Relief Valve Pressure Test
The traction charge circuit is designed to replace loss of
hydraulic fluid from the closed loop traction circuit. The
charge relief valve pressure test will identify if charge
pressure is correct.
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine for approximately ten
(10) minutes.
2. Park machine on a level surface with the cutting units
lowered. Make sure engine is off and the parking brake
is engaged. Make sure the hydraulic tank is full.
CAUTION
Before continuing further, read and become fa-
miliar with Precautions for Hydraulic Testing.
3. Install 1000 PSI (70 bar) pressure gauge with hy-
draulic hose attached to test port in the tee fitting on the
bottom of the control manifold (Fig. 18).
4. Make sure that traction pedal, steering wheel and
joystick are in the neutral position.
5. Start engine and run at low idle speed. Check for hy-
draulic leakage at pressure gauge and correct before
proceeding with test.
6. Move throttle so engine is running at high idle speed
(2710 + 50 RPM).
7. Pressure gauge should read approximately 100 to
150 PSI (7 to 10 bar).
8. Shut off engine. Record test results.
9. If specification is not met, remove piston pump back
plate assembly that contains the charge relief valve (see
Piston (Traction) Pump Service in the Service and Re-
pairs section of this chapter). Repair or replace relief
valve components as necessary.
Greensmaster 3250--D
10.A dynamic charge pressure test can be performed as
follows:
A. Position machine so that a load can be placed on
the traction system. For example, chain the machine
to an immovable object or chock all drive wheels to
prevent the machine from moving.
B. With pressure gauge still connected, sit in the op-
erator seat, start the engine and move throttle so en-
gine is running at high idle speed. Move functional
control lever to the transport position.
C. While monitoring the pressure gauge, push the
traction pedal in the appropriate direction (forward or
reverse) to allow traction system load.
D. The charge pressure should drop no more than
20% from no--load charge pressure measured in
step 7 above (e.g. if charge pressure in step 8 is 125
PSI (9 bar), charge pressure in forward or reverse
under load should be more than 100 PSI (7 bar)).
E. If charge pressure is good under no load, but
drops below specification when under traction load,
the piston (traction) pump and/or wheel motors
should be suspected of wear and inefficiency. When
the pump and/or traction motor(s) are worn or dam-
aged, the charge pump is not able to keep up with in-
ternal leakage in traction circuit components. Further
testing of the traction circuit should be completed
(see Piston (Traction) Pump Flow and Wheel Motor
Efficiency Tests in this section).
11. When charge pressure testing is complete, discon-
nect pressure gauge from the test port and install dust
cap.
FRONT
1. Control manifold
Page 4 - - 31
1
2
Figure 18
2. Test port
Hydraulic System