Suspension and Steering Latest Update Exam
Questions and Answers 100% Correct
What are heavy duty front axles?
They are forges solid I-beams.
How are heavy duty front axles mounted?
Heavy duty front axles are mounted to the leaf springs and retained with U-bolts.
What should be considered when inspecting an axle?
Perform a thorough visual inspection to identify looseness and shifted or broken parts.
Inspect the U-bolts and shims for for proper torque and placement.
Measure the front wheel set back on both wheels and compare because a difference in
measurement could be caused by a bent axle, or worn, misaligned components (i.e. spring eye
bushings.
Check the axle for twist using a machinist's protractor.
What should you pay particular attention to, if the front axle must be removed?
Pay particular attention to spacers and castor shim placement.
How would you ensure proper placement when you reinstall the front axle?
Be sure to mark the front of the axle to ensure proper placement when reinstalled.
Why should you always replace the U-bolt when installing the front axle?
U-bolt threads stretch during initial installation and scale and rust buildup may prevent improper
pull-up torque and insufficient clamping force.
,What is a knuckle pin also consider by some OEMs?
The kingpin.
What are the two designs of kingpins?
Straight or tapered designs.
What does a kingpin do?
The kingpin connect the I-beam to the steering knuckle and act as pivots to turn the front wheels.
What could a loose kingpin or kingpin bearing cause?
Could cause a shimmy with slight vibrations.
What is a dial indicator used for?
is used to measure vertical play, upper and lower bushing freeplay, and upper and lower bushing
torque deflection in the steering knuckle.
How is vertical end play adjusted?
Vertical end play is adjusted by adding or removing shims to obtain the manufacturer's clearance
specifications.
When will the bushing need to be replaced?
Should be replace if the bushing freeplay measurements are out of spec.
What should you do when greasing a front axle kingpin?
Place a jack under the front axle and raise the vehicle to unload the suspension.
How should you grease the upper bushing?
, Grease the upper bushing until grease appears between the steering knuckle and the top of the
axle eye.
How should you grease the lower bushing?
Grease the lower bushing and continue greasing until grease begins to leak out through the pivot
bearing. This shows a thorough distribution of the grease.
What is the procedure for replacing the kingpins?
When replacing the kingpins, remove the upper and lower knuckle caps to access the kingpins.
Remove the draw key nut and drive out the draw key, then press out the kingpin from the
knuckle.
Prior to assembly, check the axle eye bore for wear.
What does the draw key do?
The draw key keeps the kingpin aligned and tight in the axle bore.
When reassembling the assembly, torque the draw key nut to the manufacturer's specification.
The draw key torque should also be checked at every preventive maintenance inspection.
What happens when a vehicle hits a bump?
The wheel and suspension move upward in relation to the chassis. This causes jounce and
rebound.
What do shock absorbers do?
Dampen or control spring action from jounce and rebound, reduce body sway, and improve
directional stability and driver comfort.
Questions and Answers 100% Correct
What are heavy duty front axles?
They are forges solid I-beams.
How are heavy duty front axles mounted?
Heavy duty front axles are mounted to the leaf springs and retained with U-bolts.
What should be considered when inspecting an axle?
Perform a thorough visual inspection to identify looseness and shifted or broken parts.
Inspect the U-bolts and shims for for proper torque and placement.
Measure the front wheel set back on both wheels and compare because a difference in
measurement could be caused by a bent axle, or worn, misaligned components (i.e. spring eye
bushings.
Check the axle for twist using a machinist's protractor.
What should you pay particular attention to, if the front axle must be removed?
Pay particular attention to spacers and castor shim placement.
How would you ensure proper placement when you reinstall the front axle?
Be sure to mark the front of the axle to ensure proper placement when reinstalled.
Why should you always replace the U-bolt when installing the front axle?
U-bolt threads stretch during initial installation and scale and rust buildup may prevent improper
pull-up torque and insufficient clamping force.
,What is a knuckle pin also consider by some OEMs?
The kingpin.
What are the two designs of kingpins?
Straight or tapered designs.
What does a kingpin do?
The kingpin connect the I-beam to the steering knuckle and act as pivots to turn the front wheels.
What could a loose kingpin or kingpin bearing cause?
Could cause a shimmy with slight vibrations.
What is a dial indicator used for?
is used to measure vertical play, upper and lower bushing freeplay, and upper and lower bushing
torque deflection in the steering knuckle.
How is vertical end play adjusted?
Vertical end play is adjusted by adding or removing shims to obtain the manufacturer's clearance
specifications.
When will the bushing need to be replaced?
Should be replace if the bushing freeplay measurements are out of spec.
What should you do when greasing a front axle kingpin?
Place a jack under the front axle and raise the vehicle to unload the suspension.
How should you grease the upper bushing?
, Grease the upper bushing until grease appears between the steering knuckle and the top of the
axle eye.
How should you grease the lower bushing?
Grease the lower bushing and continue greasing until grease begins to leak out through the pivot
bearing. This shows a thorough distribution of the grease.
What is the procedure for replacing the kingpins?
When replacing the kingpins, remove the upper and lower knuckle caps to access the kingpins.
Remove the draw key nut and drive out the draw key, then press out the kingpin from the
knuckle.
Prior to assembly, check the axle eye bore for wear.
What does the draw key do?
The draw key keeps the kingpin aligned and tight in the axle bore.
When reassembling the assembly, torque the draw key nut to the manufacturer's specification.
The draw key torque should also be checked at every preventive maintenance inspection.
What happens when a vehicle hits a bump?
The wheel and suspension move upward in relation to the chassis. This causes jounce and
rebound.
What do shock absorbers do?
Dampen or control spring action from jounce and rebound, reduce body sway, and improve
directional stability and driver comfort.
