Domestic Series 7000 Hydraulics
22
9. TANDEM PUMP
9.1. Attachments are covered in a separate section.
This section covers the portions of the hydraulic
system that remain permanently attached to the
tractor.
NOTE: Unless stated otherwise, it is not neces-
sary to remove the fenders to perform the tests
described in this section. Some of the figures in
this section show the fenders removed. This
was done for photographic purposes, not for
mechanical purposes.
9.2. If there is a performance problem with an attach-
ment controlled by the loader valve, confirm that
adequate flow and pressure are being delivered
to the loader control valve by the tandem pump.
9.3. The output of the tandem pump may be checked
at the line to the loader valve, or at the line from
the loader valve to the return manifold.
See Figure 9.3.
NOTE: Because there is no power beyond from
the loader control valve, there is only one return
path for the hydraulic fluid.
NOTE: A pressure and flow test performed in
either line will yield valid results.
9.4. To gain easy access to the loader valve:
• Lift, and safely suppport the right rear of the trac-
tor.
• Remove the right rear tire using a 21mm
wrench.
9.5. Disconnect either hydraulic tube between the
bracket / bulkhead fitting on the frame, and the
loader valve. Use a 7/8” wrench and a 1”
wrench to disconnect the tube. See Figure 9.5.
9.6. Install the test kit with the pressure gauge near-
est the source of pressure.
• If testing on the line from the pump to the valve,
the pressure gauge should be near the pump.
• If testing on the line from the valve to the return
manifold, the pressure gauge should be near teh
valve.
9.7. Confirm that no unsafe conditions will result from
starting the tractor and operating the hydraulic
system. Confirm that the valve on the test kit is
fully open.
9.8. Start the engine, and allow the hydraulic fluid to
warm-up if necessary.
9.9. Set the throttle to maintain 3,000 RPM.
Figure 9.3
Bulkhead fittings
Return
manifold
Figure 9.5
Pressure line fro
tandem pump
Line to return
manifold
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