What Do Control Arms Do? Types and Common Failures

Function

Control arms link the wheel to the body/subframe, guiding vertical travel while carrying longitudinal and lateral forces.

Types

• A-arm: Double-wishbone, strong laterally
• I-arm: Most common MacPherson lower arm, with two bushings
• H-arm: Multi-link rear, high load
• Aluminum: Light, premium (check cracks after impacts)

Failures

• Bushings: cracked/separated - loose, pull, noise
• Ball joint: play - clunk, alignment drift
• Bent arm: impact - alignment impossible
• Alu cracks: fatigue risk - inspect

Symptoms

• Clunk/squeak over bumps
• Noise on braking dive
• Pull, tire wear
• Unstable at speed

Huami supplies arms, bushings and ball joints to OE standard.