How to Replace Struts on Most Vehicles

Does your car ride more like a bouncy house than an automobile? Does your front end sound like 14 pennies in a tin cup every time you hit a bump? Those are symptoms of a strut that has reached the end of its service life. Chances are you need to replace your front struts as your vehicle puts on the miles. Most vehicles today use a specialized suspension system where the coil springs and shocks are an integrated unit called a strut. The most common design is the Macpherson strut. So what does it take to replace struts on most vehicles?

What Is a Suspension Strut?

The Macpherson strut was designed by Earle Macpherson in the 1940s. Commonly used at the front of the vehicle, Macpherson struts are also sometimes used in the rear of the vehicle as well. The strut supports the weight of the vehicle and manages the shock duties as well. When the shock component of a strut goes out, the entire assembly must be removed, you can purchase the main body of the strut with or without the spring. The upper mount is also a consumable item, typically made of hard rubber and plastic. When the upper mount wears out or breaks, you end up with a rattling suspension and in severe cases, an extremely dangerous situation. Struts should also be replaced in pairs, because if one side has gone bad it is highly likely the other side is worn out as well.

Getting Ready To Replace Struts

Replacing a car strut can be done in your garage; however the spring is under a great deal of tension. Removing the spring is incredibly dangerous and requires a great deal of attention and care. You need a special tool to compress the spring so that the spring cap can be removed. This is called a Macpherson strut compressor, and they can be purchased  from any NAPA Auto Parts Store. If you aren’t comfortable compressing the spring, you can always purchase a complete strut assembly that has the hard work done already. Known also as a “quick strut”, a strut assembly is also a great time saver.

Beyond the spring issue, replacing struts for cars is a fairly straight-forward process. Typically, removing the strut involves removing the strut from the steering spindle, though some vehicles have the steering spindle built into the strut. Most vehicles do not require breaking down the ball joints, but some do. This is usually so that the lower suspension can be dropped enough to take the pressure off of the spring so that the strut can be removed.

We’re covering a generic overview of what it would take to replace struts on most vehicles. For detailed strut replacement instructions, we recommend you get a repair manual for your exact year/make/model vehicle. Either a traditional paper manual or a digital version will work just fine.

Swapping a Strut

As with any time you are working under a car, always support the vehicle on stable ground (never on dirty or gravel) with a set of jack stands. NEVER work under a car supported by only a jack. With the vehicle properly supported, you can begin by removing the wheel.

With the wheel off, the next step is to remove the lower strut bolts. Leave the bolt in place, just break it loose or remove the nut.

Some vehicles, such as this 2009 Challenger, have an upper control arm which requires breaking down the ball joint. The cotter pin and nut are removed first.

Then a tie-rod separator is used to pop the joint out of the spindle. Once the separator is tight, a few taps with a hammer should pop it loose.

Now the upper strut bolts are removed. This should allow the strut assembly to drop out of the chassis.

This is a bad upper mount from a 2001 Mercury Cougar. This vehicle was in really bad shape, the struts were just rattling around in the inner fender.

Removing the spring from the strut is the most challenging part. While most mechanic shops have a wall-mounted spring compressor, the DIY garage can get the job done safely and quickly with a bolt-on strut spring compressor. These are two-piece tools that use bolt-on loops which are attached to threaded rods. The two rods are slowly tightened which collapses the spring. NEVER attempt to disassemble a strut without properly compressing and holding the coil spring. The stored energy held in a compressed coil spring is massive and will be released explosively if the center retaining nut is removed without proper precautions.

Once the spring is compressed enough, the center nut on the top of the strut can be removed, allowing the top cap to come off and the spring removed from the strut body. Carefully release the pressure on the spring by slowly unthreading the rods a little at a time in equal amounts between the two.

Installation is the reverse of the removal; each spring must be compressed, installed and then slowly decompressed in the assembly.

With the new strut assembled, it is slid into the chassis and bolted down.

Any time you replace suspension/steering components, the vehicle must be aligned. While it may not seem like a big deal, a misalignment of even a half degree can wreck your tires in just a few hundred miles, not to mention poor handling characteristics. As with any mechanic work, if at any point you do not feel comfortable, please take it to any NAPA Auto Care service center for assistance.

Check out all the struts and suspension parts available on NAPAOnline or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to replace struts, chat with a knowledgeable expert at your local NAPA Auto Parts store.