Bulletin 2751-001-M1/USA
Service Manual
HGA Hydraguide™
Hydraulics
Parker Hannifin Corporation
Hydraulic Pump/Motor Division
Greeneville, Tennessee
24
Oil & Hydraulic Fluid
FILLING AND AIR BLEEDING THE
SYSTEM WHEN DRAINED OF OIL
1. Fill reservoir nearly full. Be ready to add oil when
the engine is started. Do not let oil level drop below
the inlet to the power pump so that the power
pump will not suck air into the system.
2. Start engine and let it idle. Immediately add oil to
the reservoir as needed.
NOTE: This oil will now be circulating only from
the power pump to and through part of the
HGA control valve and to the reservoir and
back to the power pump.
When no more oil can be added and oil is clear,
proceed as follows.
3. With one finger on a spoke of the steering wheel,
spin wheel as rapidly as possible to bleed the air in
the steering cylinder(s) and lines.
4. Immediately upon HGA valve spool actuation oil
must be added to the reservoir — to replenish the
oil moving into the circuit.
5. Keep rotating the steering wheel to keep the HGA
valve spool actuated. Do this until the road wheels
have reached the stop in that direction, then
quickly reverse the steering wheel rotation to
actuate the HGA valve spool in the opposite
direction.
6. Keep rotating the steering wheel left and right from
stop to stop of the road wheels to bleed out air.
Replenish oil as necessary.
7. The air will bleed out only at the reservoir, there-
fore, the oil must be circulated in both directions
repeatedly until the air has bled out.
NOTE: The oil in the lines to the power cylinder
reaches a “dead end” at the piston. The oil in
the cylinder does not flow in a circuit. As the
piston moves back and forth the oil moves
back and forth in the lines. Therefore, air in
these lines and the cylinder may be slow
moving into the HGA control valve and to the
reservoir.
CAUTION: Do not operate vehicle until air is
bled out.
8. When the oil in the reservoir is clear (not cloudy or
creamy), the system is free of air. (Slight creep or
drift of the steering wheel is normal.)
9. Adjust the oil to recommended level in reservoir
and assemble reservoir cover.
10. Always fill reservoir to recommended level.
HYDRAULIC FLUID
Keep the steering system filled with one of the
following:
• Automatic Transmission Fluid Type “F”
• Automatic Transmission Fluid Dexron II
• Hydraulic fluid as recommended by the vehicle
manufacturer.
WARNING: DO NOT MIX OIL TYPES, ANY
MIXTURE, OR AN UNAPPROVED OIL, COULD
DETERIORATE THE SEALS. ENOUGH FLUID
COULD THEN LEAK TO CREATE A LOSS OF
POWER STEERING ASSIST. DO NOT ALLOW
FLUID LEVEL TO GO BELOW FILL LINE ON
DIPSTICK. BEFORE ADDING NEW FLUID,
COMPLETELY DRAIN OLD OIL FROM THE
SYSTEM. IT MAY BE NECESSARY ALSO THAT
YOU FLUSH THE SYSTEM WITH CLEAN OIL.
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