1. McPherson Strut Service and Diagnosis
Consumer Auto Suspension Lecture 2

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

3. 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

4. Steering Knuckle Function
Connects lower control arm to strut
Swivels on ball joint and upper bearing

5. Stabilizer Bar Function
Connects left and right lower control arm
Connected to vehicle body
Reduces body roll

6. Strut Rod Function Connects lower control arm and frame
Holds control arm in position, keeps wheels in alignment

7. Diagnosing Noise Problems
Loose mountings
Loose or damaged struts
Worn or damaged ball joints
Worn control arm or stabilizer bushings

8. Diagnosing Ride Height Problems
Damaged or broken parts
Broken or fatigued springs
Misaligned body mountings

9. Diagnosing Body Roll Problems
Bad struts
Worn stabilizers
Worn control arm bushings
Worn ball joints

10. 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

11. 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

12. Steering Knuckle Inspection
Check for damage

13. Stabilizer Bar and Links Inspection
Check for damage and broken/missing bushings
Check for bent parts
Check for loose bolts

14. Strut Rod Inspection Check for bending Check frame bushings
Check for loose bolts or nuts

15. Check Connections to Other Parts
Tighten bolts and nuts

16. Lubrication Use recommended grease
Follow lube schedule in the owners manual

17. Suspension Parts are Not Repairable
Repaired suspension parts are NOT SAFE!!!
Repaired suspension parts wear out much quicker

18. Front End Alignment
Needed after the control arm, steering knuckle or strut has been changed
Not necessary after stabilizer (sway bar) replacement

19. Stabilizer Bar Replacement
Unbolt sway bar brackets
Unbolt link assemblies and replace

20. Strut Rod Replacement 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

21. 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

22. Lower Control Arm Replacement
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

23. That Concludes Suspension Lecture 2