Landoll Bendi B40i4, Руководство по обслуживанию

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TROUBLESHOOTING AND CORRECTIVE MAINTENANCE
3-33
Hydraulic Control Valve
1. First, review “Before You Begin,” page 1-1.
2. Set the key switch to “OFF” and remove the key from
the ignition switch.
3. Apply the parking brake, disconnect the battery and
block the wheels.
4. Relieve pressure in the system by turning the
steering wheel two times to the left, then two times to
the right and move the control levers in both
directions.
5. Remove the control valve cover to expose the
hydraulic control valve. See Figure 3-22.
6. Determine the suspect valve spool and remove it
from the hydraulic control valve and locate where the
leak is occurring and/or determine which valve spool
is defective. See Figure 3-4.
NOTE
All valves include external O-ring seals which are
serviceable. However on pressure valves the internal
mechanism is not serviceable and must be replaced as a
complete unit.
7. Disconnect the control levers (three) from the valves
and tag the levers for identification.
8. Disconnect hoses at fittings and immediately plug or
cap all lines. Tag the lines for identification during
reassembly.
9. Remove the two hex nuts and hardware holding the
valve assembly to the truck base. Lift the valve from
the truck and place it on your workbench. It is heavy
so be prepared.
10. If a valve is being replaced, remove the hydraulic
fittings from the defective valve and note how the
fittings are arranged.
11. Before placing the truck back into operation, test it to
make sure all functions are operating properly and
that there are no oil leaks.
12. If the hydraulic control valve manifold is being
replaced:
• Clean the mating surfaces of the valve spools and
make sure the O-ring seal is properly seated before
sealing the parts together.
• Disconnect hoses at the fittings and immediately
plug/cap all lines. Have shop rags handy to manage
spills.
• Remove the fittings from the defective valve and note
their alignment, then remove the mounting hardware
and replace the valve.
• Install the fittings in the replacement valve
maintaining proper alignment.
IMPORTANT
When reinstalling the valve be certain to tighten the
mounting screws in a staggered fashion while
applying equal pressure to all screws. If the screws
are not tightened and torqued evenly, you could
create a stress crack, thus internal oil leaks,
rendering the valve defective.
• When installing fittings, apply a light film of oil to the
O-ring seal and do not overtighten. Excessive
pressure could damage the seals.
• If the pressure relief valve is being replaced, you
must readjust the pressure setting before operating
the truck. See "To Check and/or Adjust Pressure,"
below.
• Reassemble in reverse order.
Figure 3-24: Pressure Adjustment Screw
Steer System Relief Valve
The Bendi B40i4 is equipped with a load sense power
steering system. This system only uses the fluid that is
required by the steering system. The relief valve for the
steering system is found in the steering orbital (See
Figure 3-24) where the orbital connects to the steering
column. The hole that the screw is recessed into comes
filled with easy to remove plastic which must be removed
to access the pressure adjust screw. Power steering
pressure is set at 1900 psi ±65 psi (18 MPa, ±0.3 MPa).
A pressure gauge port is provided, with a “quick-coupler,”
(pressure service kit, Landoll p/n: 0018152) for reading
the steer pump pressure.
NOTE
Before you service this valve for possible pressure
problems, make sure there are no leaks in the hydraulic
system and that there is sufficient oil in the tank. Both
conditions can contribute to low pressure problems.