Transcript Module 7A9 - Teknik Otomotif

McPherson Strut Service and
Diagnosis
Consumer Auto Suspension Lecture 2
How McPherson Struts Work
• Struts combine coil spring, shock, and
upper control arm
• Upper bearing provides a place for the strut
to swivel
• Helps keep wheel in contact with the road
• How the strut is attached to the car is
critical for wheel alignment
Lower Control Arms Function
• Connect frame to
steering knuckle
• Has bushings on one
end, a ball joint on
the other
• Uses a rubber
bumper to prevent
metal to metal
contact
Steering Knuckle Function
• Connects lower
control arm to strut
• Swivels on ball
joint and upper
bearing
Stabilizer Bar Function
• Connects left and
right lower control
arm
• Connected to
vehicle body
• Reduces body roll
Strut Rod Function
• Connects lower
control arm and
frame
• Holds control arm
in position, keeps
wheels in alignment
Diagnosing Noise Problems
• Loose mountings
• Loose or
damaged struts
• Worn or
damaged ball
joints
• Worn control arm
or stabilizer
bushings
Diagnosing Ride Height Problems
• Damaged or
broken parts
• Broken or
fatigued
springs
• Misaligned
body
mountings
Diagnosing Body Roll Problems
• Bad struts
• Worn
stabilizers
• Worn control
arm bushings
• Worn ball
joints
Control Arms Inspection
• Raise vehicle, inspect
for signs of damage
• Pull and push wheel
to check for ball joint
wear
• Use pry bar to inspect
for arm bushing
movement
MacPherson Strut Inspection
• Check for oil leaks, bent piston rod or other
parts
• Check springs for damage or breaks
• Turn wheel from stop to stop and listen for
noise
• Check shock for proper operation
Steering Knuckle Inspection
• Check for damage
Stabilizer Bar and Links
Inspection
• Check for damage
and broken/missing
bushings
• Check for bent
parts
• Check for loose
bolts
Strut Rod Inspection
• Check for bending
• Check frame
bushings
• Check for loose
bolts or nuts
Check Connections to Other
Parts
• Tighten bolts and
nuts
Lubrication
• Use recommended grease
• Follow lube schedule in the owners manual
Suspension Parts are Not Repairable
• Repaired suspension parts are NOT
SAFE!!!
• Repaired suspension parts wear out much
quicker
Front End Alignment
• Needed after the
control arm, steering
knuckle or strut has
been changed
• Not necessary after
stabilizer (sway bar)
replacement
Stabilizer Bar Replacement
• Unbolt sway bar brackets
• Unbolt link assemblies and replace
Strut Rod Replacement
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Raise and support vehicle
Unbolt from the frame
Unbolt from the control arms
Remove bolt from lower control arm
Install new strut rod, bolt to frame, and
control arms
• Reinstall bolt in lower control arm
• Torque to specifications
MacPherson Strut Replacement
• Raise and support vehicle
• Mark adjustment cam on lower attachment
point
• Unbolt lower and upper attachment
• DO NOT remove shock nut in center
• Remove strut and replace
• Replace all one-time fasteners
Lower Control Arm Replacement
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Raise and support vehicle
Remove wheel and support
Disconnect strut rod and stabilizer bar
Separate ball joint, unbolt from frame
Replace ball joint, bushings
Install new part
That Concludes Suspension
Lecture 2