Service Manual

25
Before Performing Hydraulic Tests
ALL OBVIOUS AREAS SUCH AS OIL SUPPLY,
FILTERS, IMPROPER ADJUSTMENT BINDING
LINKAGE, OR LOOSE FASTENERS MUST BE
CHECKED BEFORE ASSUMING THAT A HY-
DRAULIC COMPONENT IS THE SOURCE OF
THE PROBLEM BEING EXPERIENCED.
1. Thoroughly clean the machine before discon-
necting or disassembling any hydraulic compo-
nents. Always keep in mind the need for cleanli-
ness when working on hydraulic equipment.
2. Put caps or plugs on any hydraulic lines left open
or exposed during testing or removal of compo-
nents.
3. The engine must be in good operating condition.
Always use a tachometer when doing a hydraulic
test. ENGINE SPEED WILL AFFECT THE ACCU-
RACY OF THE TESTER READINGS.
4. To prevent damage to the tester or components,
the inlet and outlet hoses must be properly con-
nected and not reversed (tester with pressure and
flow capabilities).
5. To minimize the possibility of damaging the
components, completely open the load valve by
turning it counter clockwise (tester with pressure
and flow capabilities).
IMPORTANT: Pumps used on Toro equipment
are of a positive displacement type. If a tester is
installed in a portion of the circuit not protected
by a relief valve and the pumps output flow is
completely restricted or stopped, damage to the
pump or other components could occur.
6. Install fittings finger tight, far enough to insure
that they are not cross-threaded, before tightening
them with a wrench.
7. Position the tester hoses so that rotating ma-
chine parts will not make contact with them and re-
sult in hose damage.
8. Check the oil level in the reservoir.
9. Check the control linkage for improper adjust-
ment, binding or broken parts.
10. All hydraulic test should be made with the hy-
draulic system at normal operating temperature.
11. Use gauges of proper pressure ratings when
performing hydraulic tests.
12. Always keep safety in mind while performing
tests. Keep bystanders away from the equipment.
HOOK UP NO. 1
TEST A: PUMP FLOW
Connect the tester in series with the pump output
circuit, (Fig 7) and shift the spool valve to the neu-
tral (off) position, we can then measure the pump
output to insure that the oil flow is adequate to
drive the motor at the desired speed. Use extreme
caution when using this procedure. There is no
relief valve between the pump and the restrictor
valve when tested in this manner. Be absolutely
sure the flow meter is open when starting the
engine.
TEST B: MECHANICAL BINDING
Using the same hookup as in test A, if we shift the
spool valve to the run position, we can observe the
pressure gauge reading and verify the pressure re-
quired to rotate the hydraulic motor.
Figure 7