Toro Reelmaster 7000-D Service Manual page 127

Traction Circuit − Rear Relief Valve (RV) Pressure
Test
The adjustable rear relief valve (RV) in the rear traction
manifold reduces rear axle motor pressure created in
down hill, dynamic braking conditions to prevent rear
wheel lock up. Check the rear relief valve (RV) pressure
if the rear wheels lock up during dynamic braking condi-
tions (setting too high) or if poor traction performance
when in reverse is suspect (setting too low or too close
to pressure reducing valve (PR) setting).
Special Equipment Required:
S Pressure Gauge − 1000 PSI (70 bar) with hose
S Diagnostic Fitting w/Cap − 9/16 − 18
S Phototach (non−contact tachometer) for units
with Kubota diesel engine
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.
1. Park machine on a level surface with the cutting units
lowered and disengaged. Make sure engine is off and
the parking brake is engaged.
NOTE: The #6 zero leak plug on the rear traction mani-
fold has a tapered sealing surface on the plug head.
Lightly rap the plug head using a punch and hammer be-
fore using an allen wrench to remove the plug. The im-
pact will allow plug removal with less chance of damage
to the socket head of the plug.
2. The rear traction manifold is attached to the frame
near the left front wheel motor (Fig. 37). Remove the #6
zero leak plug from the unmarked port located between
ports M8 and P2 and install a diagnostic fitting.
3. Connect a 1000 PSI (70 bar) pressure gauge with hy-
draulic hose attached to installed diagnostic fitting. The
pressure gauge hydraulic hose must be long enough to
safely view the pressure gauge while sitting in the opera-
tor's seat.
4. Start engine and run at low idle speed. Check for hy-
draulic leakage and make corrections if necessary be-
fore proceeding with test.
5. Set throttle to high speed.
A. Use the InfoCenter display to verify engine RPM
on units with Yanmar diesel engines (2850 RPM).
B. Use a phototach to verify engine RPM on units
with Kubota diesel engines (2850 +50/−120 RPM).
Reelmaster 7000−D
1 2
FRONT
1. Rear traction manifold
2. Unmarked port
6. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine for approximately ten
(10) minutes.
7. Sit in the operator's seat, set the mow speed limiter
to the LOW speed (mow) position, and release the park-
ing brake.
8. Operate the machine with the cutting units lowered.
Drive down a slope in the forward direction, release the
traction pedal and monitor the pressure gauge. Pres-
sure should increase until the rear relief valve (RV)
opens.
GAUGE READING TO BE: 520 to 570 PSI (36 to 39
bar) and at least 100 PSI (7 bar) higher than the
reverse reducing valve (PR) pressure (e.g. if the
pressure reducing valve (PR) pressure is 450 PSI
(31 bar), relief (RV) pressure should be at least 550
(38 bar) or slightly higher).
9. Release traction pedal, set parking brake, and stop
engine. Record test results.
10. Before adjusting rear relief valve (RV), make sure
that pressure reducing valve (PR) pressure is correct
(see Traction Circuit − Reverse Reducing Valve (PR)
Pressure Test in this manual).
11. The rear relief valve (RV) is located on the bottom of
the rear traction manifold (Fig. 37). If test pressure is in-
correct, adjust rear relief valve (RV) (see Adjust Control
Manifold Relief Valves in this chapter). Recheck rear re-
lief valve pressure after any adjustment.
12.When testing is completed, disconnect pressure
gauge and hose. Leave the diagnostic fitting installed for
future testing and reverse towing bypass. install a diag-
nostic fitting cap to protect the fitting and prevent system
contamination.
Page 5 − 57
3
Figure 37
3. Rear relief valve (RV)
Hydraulic System