Steering Boxes

1
Steering Boxes

• Steering Lecture 5

2
Steering Gear Types

• There are two types of steering gears
• Worm and Roller
• Recirculating Ball
• These are found in both manual and power steering
  systems

3
Worm and Roller Steering Gear

• In this gear, the hourglass shaped worm (white)
  is rotated by the steering shaft
• The roller (red) on the sector shaft (blue) moves
  with the worm, making the turning effort easier
  because of less friction
• The sector shaft (blue) is
  connected to the pitman
  arm (yellow)

4
Recirculating Ball Type

• In this gear, the worm (white) is rotated by the
  steering shaft
• Between the worm and ball nut (blue) are several
  ball bearings that reduce friction on the worm

5
Recirculating Ball Type

• The ball nut has a gear on it and turns the
  sector gear (red), which is connected to the
  pitman arm
• The ball bearings ride inside the ball nut and
  are returned to the front

6
Steering Box Adjustments 1

• Centering the steering wheel
• Raise the truck and turn the steering wheel all
  the way to the end
• Turn the other way and count the turns
• Turn it back half way
• Measure the distance between the front of the
  tire and frame against the back of the tire and
  frame
• Should be within 1/8
• To adjust, lengthen or shorten the drag link

7
Steering Box Adjustments 2

• Worm Bearing Preload
• With the drag link and steering shaft
  disconnected, connect an inch pound torque wrench
  to the input shaft
• Move the input shaft back and forth ¼ turn and
  note the reading
• Compare with manufactures specs
• If loose, remove shims or tighten the adjuster
• If tight, add shims or loosen adjuster

8
Steering Box Adjustments 3

• Total Mesh Preload
• After checking the worm preload, center the gear
  and adjust the sector shaft to zero backlash
• Take a wrench and rotate from end to end and note
  any difference in effort required to turn
• If it is harder in the middle, back off the
  sector adjustment slightly

9
Steering Box Adjustments 4

• Centering the steering box
• With the steering box installed, remove the
  steering shaft and drag link
• Rotate the input shaft all the way to the left
  and mark, then rotate all the way to the right
  and mark
• Find the half way point and
  mark
• Turn back ½ the amount of turns
• The drag link should connect