11/14/2025
Repairs de-mystified: SUSPENSION.
Our next subject is one that matters a lot going into winter, and has a lot of parts and design variants which can make understanding these repairs difficult.
First off, the obvious question: why should I care? Suspension affects tire contact with the road. Better alignment, better traction, safer driving.
How does it work? This takes a bit to answer, mainly because there are multiple designs. Essentially, control arms act like a human elbow while the famous (or infamous) ball joints work like a wrist. Struts/shocks act like the muscles controlling the rate and level of movement.
The picture included shows the 3 main types: MacPherson, double wishbone, and multi-link. MacPherson is often on smaller vehicles, and the strut acts like upper control arm. Big vehicles, like large SUV and trucks often have the double wishbone since it takes heavier loads better. Multi-link is most often on sports vehicles or luxury vehicles where performance and comfort are emphasized over ease of maintenance.
A strut is often called a shock, but they are not actually the same. A strut is the assembly including the shock, the coils, shock mounts. In the MacPherson setup, a strut is the upper control arm. In large vehicles, the strut works in tandem with the upper control arm.
And then the famous ball joints. These connect the control arms to the wheel knuckle, which is what the wheel and brake parts all mount to. A ball joint is a great solution to the multiple travel directions required, but it also makes it a weak point to fail.
Alignment goes with replacement of these parts because of how all these parts interact. If the ball joint fails, the knuckle is wiggling and tire wear is not even. If the control arm or strut bushings (bits of rubber mounting these parts to the frame) fail, same thing since as they wiggle tire wear is not even. Alignment is required with new parts to ensure the tires are perpendicular to the road for proper wear and braking/steering control. A couple degrees make a big difference. Alignment ensures tires wear and grip even. You don't want to have to buy new tires before you have to after all!
