Steering Systems
Driver Input
• When the steering wheel
is rotated from lock-to-lock
the the front wheels turn
about 30 degrees in each
direction or 60 degrees
total
• A steering ratio of 15:1 is
common for passenger
cars
• fifteen degrees of
steering wheel rotation
moves the front tires one
degree
• Variable ratio
Steering and Suspension
Steering Wheel and Column
• The steering wheel,
column, u-joints and
flex couplings deliver
the driver’s input to the
steering gear, provide
vehicle feedback to the
driver and insulate the
driver from excessive
road feel or harshness
• The steering column is
also deigned to collapse
during a collision
Steering and Suspension
Parallelogram Steering
• The parallelogram
linkage insulates the
driver from road noise
and vibration, but
component wear leads
to a feeling of steering
looseness
• Pitman arm
• Center link
• Idler arm
• Tie rods
• Tie rod ends
Steering and Suspension
Idler Arm
• The idler arm is bolted
to the frame and
supports the center link
opposite the pitman arm
• Excessive idler arm
play may cause
steering wheel play and
allow the vehicle’s toe
setting to change while
driving or under load
Steering and Suspension
Tie Rod Ends
• Tie rods ends connect the tie
rod to the center page link and the
steering knuckle
• Tie rod ends are often
checked for proper
articulation effort
• Excessive tie rod end play
may cause steering wheel
play and allow the vehicle’s
toe setting to change while
driving or under load
• Binding tie rod ends can
cause increased steering
effort or binding
AUMT 1316 - Steering Systems 10/15/2004
2
Steering and Suspension
Recirculating Ball Gearbox
• Converts the
steering wheel’s
rotary motion into
linear motion
• Commonly used on
light trucks and
large cars
• Minimal internal
friction
• Road shock isolation
Steering and Suspension
Steering Gearbox Components
Stub Shaft
Sector Gear
Sector Shaft
Worm Shaft
Housing
Steering and Suspension
Ball-Nut Operation
• A series of ball bearings is
placed between the worm
gear and the ball nut
• The ball bearings cannot
move up or down and the
balls bearings follow the
track in the worm gear
• The ball nut follows the
ball bearings as the
steering wheel turns
• The ball nut meshes with
the sector gear
Steering and Suspension
Steering Gear to Linkage
• Steering wheel drives the
steering shaft
• Steering shaft drives the
worm shaft
• Worm shaft drives the
balls
• Balls drive the ball nut
• Ball nut drives the sector
gear
• Sector gear drives the
sector shaft
• Sector shaft drives the
pitman arm
• Pitman arm drives the
center link
• Center page link drives the
inner tie rod end
• Inner tie rod end drives
the tie rod
• Tie rod drives the outer tie
rod end
• Outer tie rod end drives
the steering knuckle
Steering and Suspension
Adjustment
• Two adjustments are
commonly required for
recirculating ball
steering gear service:
• Worm-shaft preload for
manual steering gears
• Sector-shaft mesh-load
• Sector shaft mesh-load
procedures are
commonly available for
bench and on-car
service
Steering and Suspension
Rack and Pinion Steering
• Light and compact
design
• Pinion drives rack
• Rack drives tie rods
• Tie rods drive steering
knuckle
• Fewer friction points
than parallelogram
steering
• increases road feel
• Noise and vibration
transmitted to driver