9 -1 0 STEERING
POWER STEERING SYSTEM
HYDRAULICS
Hydraulics is the science of liquids, such as water or oil.
When we study hydraulics, we learn that pressure can be
exerted through liquids, and that this pressure can
transmit motion from one place to another. The reason
for this is that liquids are incompressible. That is, they
cannot be compressed to a smaller volume.
TRANSMITTING MOTION WITH LIQUIDS
Since liquid is not compressible, motion may be
transmitted by liquid. For example, consider two pistons
in a cylinder with a liquid between them. When the
applying piston is moved into the cylinder 8 inches, then
the output piston will be pushed along the cylinder the
same distance. You could substitute a solid connecting
rod between piston A and piston B and get the same
result. But the advantage of such a system is that you can
transmit motion between cylinders at any angle or
distance. As the applying piston is moved, liquid is
forced out of cylinder A, through the tube, and into
cylinder B. This causes the output piston to move in
cylinder B.
TRANSMITTING PRESSURE WITH LIQUIDS
The pressure applied to a liquid is transmitted by the
liquid in all directions and to every part of the liquid.
For example, when a piston with 1 square inch of area
applies a force of 100 pounds on a liquid, the pressure
on the liquid is 100 psi (pounds per square inch). This
pressure will be registered throughout the entire
hydraulic system. If the area of the piston is 2 square
inches and the piston applies a force of 100 pounds, then
the pressure is only 50 psi.
With an input-output system we can determine the force
applied to any output piston by multiplying the pressure
in pounds per square inch by the area of the output
piston in square inches. For example, if the pressure is
10 psi, and the output piston has an area of 16 square
inches, the output force on this piston is 10 times 16 or
160 pounds. If a piston has an area of 2 square inches its
output force is therefore 20 pounds (10 x 2) (Fig. 13).
The bigger the output piston, the greater the output
force. If the area of the piston were 100 square inches,
for example, the output force would be 1,000 pounds.
Likewise, the higher the hydraulic pressure, the greater
the output force. If the hydraulic pressure on the
2-square-inch piston went up to 1,000 psi, then the
output force on the piston would be 2,000 pounds.
In all the preceding examplies, a piston-cylinder
arrangement was the means of producing the pressure
and this is the method used in hydraulic brakes.
However, any sort of pump or pressure-producing device
can be used. Several types of pump (gear, rotor, vane)
have been used in automatic transmissions and power
steering. G.M. Power Steering uses a constant displace
ment vane type pump.
The hydraulic power steering system consists of a pump,
an oil reservoir, a steering gear, a supply hose, and a
return hose (Figs. 14-15).
The integral power steering gear may be either constant
ratio or variable ratio. The integral power steering gear
has an open center, rotary type, three-way control valve,
which directs oil to either side of the rack piston. The
Fig. 14—Power Steering System w/L-6 Engine-
Typical
LIGHT DUTY TRUCK SERVICE MANUAL
Summary of Contents for Light Duty Truck 1973
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Page 53: ...HEATER AND AIR CONDITIONING 1A 27 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 115: ...LIGHT DUTY TRUCK SERVICE M A N U A L HEATER AND AIR CONDITIONING 1A 89...
Page 123: ...BODY 1B 3 Fig 6 Typical 06 Van LIGHT DUTY TRUCK SERVICE MANUAL...
Page 149: ...BODY 1B 29 Fig 84 Body Mounting 06 Fig 85 Body Mounting 14 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 171: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 2 Frame Horizontal Checking Typical FRAME 2 3...
Page 173: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 4 10 30 Series Truck Frame FRAME 2 5...
Page 174: ...2 6 FRAME LIGHT DUTY TRUCK SERVICE MANUAL Fig 5 Underbody Reference Points G Van...
Page 185: ...FRONT SUSPENSION 3 11 Fig 16 Toe out on Turns LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 351: ...ENGINE 6 15 Fig ID Sectional View of Eight Cylinder Engine LIGHT DUTY TRUCK SERVICE MANUAL...
Page 375: ...EN G IN E 6 39 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 376: ...6 4 0 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 377: ...ENG IN E 6 41 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 378: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 37L K Series Engine Front Mount 6 42 ENG INE...
Page 400: ...6 6 4 ENG INE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 401: ...ENG IN E 6 65 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 402: ...6 6 6 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 403: ...E NG IN E 6 67 Fig 36V C Series Engine Mounts LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 423: ...EN G IN E C OOLING 6K 13 Fig 16 Overheating Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 424: ...6 K 1 4 ENG INE COOLING Fig 17 Coolant Loss Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 456: ...6M 32 ENGINE FUEL Fig K15 Accelerator Controls G Van L 6 LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 512: ...Fig 18e Vacuum Advance Diagram V8 Engine...
Page 516: ...6 T 2 4 E M IS S IO N CONTROL SYSTEMS LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 593: ...CLUTCHES MANUAL TRANSMISSIONS 7M 3 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 598: ...7M 8 CLUTCHES MANUAL TRANSMISSIONS LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 743: ...FUEL TANKS AND EXHAUST 8 13 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 744: ...8 14 FUEL TANKS AND EXHAUST LIGHT DUTY TRUCK SERVICE MANUAL...
Page 760: ...8 30 FUEL TANKS AND EXHAUST Fig 40 Exhaust Pipe P Models LIGHT DUTY TRUCK SERVICE MANUAL...
Page 761: ...FUEL TANKS AND EXHAUST 8 31 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 763: ...FUEL TANKS AND EXHAUST 8 33 LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 832: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 106 Power Steering Pump Mounting Typical 9 66 STEERING...
Page 833: ...PUMP ASSEMBLY STEERING GEAR TYPICAL SMALL V8 TYPICAL LARGE V8 STEERING 9 67...
Page 861: ...STEERING 9 95 Fig 134 Power Steering Pump Leakage LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 886: ...11 10 CHASSIS SHEET METAL LIGHT DUTY TRUCK SERVICE MANUAL...
Page 891: ...ELECTRICAL BODY AND CHASSIS 12 5 LIGHT DUTY TRUCK SERVICE MANUAL...
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