The steering and suspension system connects a vehicle’s wheels to its frame, controlling ride quality, handling, and the geometry that alignment angles depend on. Suspension wear is one of the leading causes of alignment angles failing to hold specification, making the two systems functionally inseparable from a diagnostic standpoint.
1. Suspension System Classifications
MacPherson Strut Systems
A combined shock absorber and structural support unit, commonly used on front-wheel-drive vehicles. The strut serves as both a damping component and a load-bearing structural member, meaning strut wear directly affects ride height and alignment geometry.
Double Wishbone / Control Arm Systems
Uses upper and lower control arms connected by ball joints, allowing more precise control over camber change through suspension travel. This design is common on performance vehicles and many trucks and SUVs.
Multi-Link Rear Suspension
Found on many modern unibody vehicles, using multiple independent links to control wheel movement in more than one plane. This design allows for adjustable rear toe and camber, which is why many modern vehicles require four-wheel alignment.
2. Component Profiles
Shock Absorbers: Hydraulic dampers that control the rate of spring compression and rebound, reducing bounce after a road disturbance.
● Struts: A structural assembly combining a shock absorber with a coil spring and mounting point, bearing part of the vehicle’s weight.
● Ball Joints: Pivoting connectors that allow the wheel assembly to move up and down while turning, located at control arm connection points.
● Tie Rod Ends: Connect the steering rack to the steering knuckle, directly controlling toe angle.
● Control Arm Bushings: Rubber or polyurethane isolators that allow controlled movement while dampening vibration and noise transfer into the cabin.
● Sway Bar Links: Connect the stabilizer bar to the suspension, reducing body roll during cornering.
3. Systematic Failure Modes and Diagnostic Protocols
Worn Shocks and Struts
Hydraulic seals degrade over time, allowing fluid to leak and damping performance to drop. Diagnostic Indicator: Excessive bouncing after passing over a bump, nose-diving under braking, or visible fluid seepage on the strut housing.
Ball Joint Wear
Repeated load cycling wears the internal bearing surface of a ball joint, introducing play into the joint. Diagnostic Indicator: Clunking noises over bumps, uneven tire wear, or measurable vertical play detected during a manual suspension inspection with the vehicle raised.
Bushing Deterioration
Rubber bushings harden, crack, or separate from their metal sleeves with age and exposure to heat and road contaminants. Diagnostic Indicator: Clunking or knocking during acceleration or braking, along with vague or imprecise steering response.
Sway Bar Link Failure
The ball-and-socket ends of sway bar links wear and develop play, most noticeable during cornering. Diagnostic Indicator: Rattling or clunking specifically when turning or during side-to-side weight transfer, absent during straight-line driving.
4. Impact on Alignment and Handling
Because alignment angles are measured relative to suspension component positions, any wear or play in ball joints, bushings, or tie rod ends prevents alignment adjustments from holding accurately. A vehicle brought in for a repeat alignment complaint shortly after a prior adjustment is a strong diagnostic indicator of an underlying worn component rather than a measurement error.
5. Preventive Maintenance and Inspection Schedules
Suspension components are typically inspected during routine service intervals or whenever a vehicle is raised for other maintenance, such as an oil change or tire rotation. Visual inspection includes checking for fluid leaks at strut housings, testing ball joints and tie rod ends for play, and inspecting bushings for visible cracking or separation. Suspension wear accelerates on roads with frequent potholes or expansion joints, making periodic inspection a standard preventive measure in regions with those road conditions.
Pete Kelley’s Auto Service Approach
Pete Kelley’s Auto Service addresses steering and suspension concerns through its Shock & Suspension service line, covering the inspection, diagnosis and repair of shocks, struts, ball joints, tie rod ends, control arm bushings and sway bar links. This service line functions closely alongside the shop’s alignment work, since suspension condition directly affects whether an alignment will hold.
Technicians evaluate suspension components using manual inspection methods , checking for play, fluid leaks and physical wear , before recommending repair or proceeding with an alignment. This diagnostic-first sequencing is part of the same ASE-certified, inspection-based service standard that has supported the shop’s A+ Better Business Bureau rating and Best of the Valley recognition since 1972.