MacPherson Strut Explained: What It Is and Why It Matters

The MacPherson strut is the backbone of most front‑wheel suspensions. It combines a shock absorber and a coil spring into one unit, letting your car’s wheel move up and down while staying pointed straight. Because it’s compact and cheap to make, almost every sedan and small SUV uses it.

How to Spot a Bad MacPherson Strut

When a strut starts to fail, the car talks to you in a few loud ways. First, listen for clunking or knocking when you drive over bumps – that’s often a worn out strut mount. Second, feel for a soft, mushy ride that suddenly gets stiff at higher speeds; the strut isn’t damping correctly. Third, check the tire wear. Uneven front‑end wear, especially a feather‑edge on the inside or outside of the tread, means the strut isn’t keeping the wheel aligned.

If you notice any of these clues, grab a friend and do a quick visual check. With the car on level ground, look at the strut’s top and bottom for oil leaks or broken rubber boots. A broken boot lets dirt in and can ruin the bearing inside the strut, causing it to wobble.

DIY Inspection and Simple Fixes

Most car owners can do a basic strut inspection in under 30 minutes. Start by loosening the lug nuts, raise the front of the car with a jack, and support it on jack stands. Remove the wheel and you’ll see the strut tower. Push down on the strut with your hand – if it moves more than a few millimetres, the internal spring may have lost its tension.

For a quick fix, replace the strut mount or the rubber boot. These parts are cheap (often under $30) and don’t require special tools beyond a socket set. Tighten the strut bolts to the manufacturer’s torque spec – usually around 80‑100 Nm – to avoid loosening later.

When the strut itself is worn out, it’s best to replace the whole unit. A new MacPherson strut typically costs $150‑$250 for the part, plus a few hours of labor. If you’re handy, you can swap it yourself by removing the tie‑rod, brake caliper, and lower control arm, then pulling the strut out of the top mount. Make sure to compress the coil spring with a proper strut compressor before removing the top nut; otherwise, the spring can snap.

Even if you’re not doing the replacement yourself, knowing the steps helps you negotiate with a shop and avoid being overcharged. Ask for a detailed quote that lists the strut, mount, and any hardware you’ll need.

Reading other car‑maintenance guides can give you more context. For example, our "What Causes Suspension Failures?" article walks through the most common reasons a suspension goes bad, and the "How to Tell If Your Suspension Is Bent" guide shows you quick visual checks you can do before you even lift the car.

Bottom line: the MacPherson strut is simple, but it’s essential for a smooth ride and safe handling. Spotting problems early, doing a basic inspection, and knowing when to replace the whole unit will keep your car handling like it should. Keep an eye on noises, ride feel, and tire wear – they’re the first signs that your strut needs attention.