What struts do and when to replace them
Struts are shock absorbers that connect your wheel to the frame and control how your car bounces after hitting a bump. When they wear out, your car will bounce excessively, pull to one side, or make clunking sounds over bumps. Most struts last between 50,000 and 100,000 miles, though this varies by driving conditions and road quality in your area.
You'll know struts need replacement when the car dips noticeably when you brake, the ride feels floaty or unstable, or you see fluid leaking down the side of the strut itself. A mechanic can confirm this by pushing down hard on each corner of the car—if it bounces more than once or twice, the struts are worn. Replacing struts is a job you can do at home with basic tools, though it requires patience and attention to detail.
Key Takeaways
- You will need a jack, jack stands, a spring compressor tool, and a socket set to safely remove and install struts without the spring launching.
- Always compress the spring before removing the strut assembly, because the spring is under extreme tension and can cause serious injury if it releases suddenly.
- Mark the position of the top strut mount before removal so you can reinstall it in the same spot and avoid alignment problems.
- The entire job takes three to four hours per side once you have the right tools, and you should replace both struts on the same axle at the same time.
- After installation, have your wheel alignment checked at a shop, because strut replacement always affects how your wheels point.
Gather your tools and parts before you start
You will need a spring compressor tool (rent one from an auto parts store for $20 to $40 for the day), a floor jack, two jack stands rated for your car's weight, a socket set with a 15mm or 18mm socket depending on your car, a wrench set, a screwdriver, and a marker or tape. Do not skip the spring compressor—the spring under the strut is compressed with hundreds of pounds of force, and releasing it without the tool can break bones or cause permanent injury.
Buy replacement struts that match your car's year, make, and model. Most cars need two struts per axle (front or rear), so decide whether you are replacing front struts, rear struts, or both. Buy both at once if you are doing one axle, because struts wear evenly and replacing only one side will cause uneven handling. Some strut kits come with new mounts and springs already assembled, which makes the job simpler—check your parts listing before you buy.
Park on a flat, level surface away from traffic. Engage the parking brake and place wheel chocks behind the rear wheels if you are working on the front, or in front of the front wheels if you are working on the rear.
Remove the wheel and disconnect the strut from the steering knuckle
Loosen the lug nuts on the wheel you are replacing while the car is still on the ground—this is much easier than trying to turn them after the wheel is in the air. Raise the car with the floor jack under the frame (not under the plastic trim), and place a jack stand under the frame as well. Lower the car onto the jack stand so the weight is fully supported, then remove the lug nuts and wheel.
Look at the bottom of the strut where it connects to the steering knuckle (the part that holds the wheel). You will see two bolts holding the strut to the knuckle. Use your socket set to remove both bolts. The strut will now hang by the top mount only. Do not let it hang freely—support it with your hand or a block of wood, because the weight can damage the top mount.
If the bolts are stuck, spray them with penetrating oil and wait 10 minutes before trying again. Do not force them, as stripping the bolt head will require drilling it out later.
Unbolt the strut from the top and compress the spring
Open your hood and look at the top of the strut tower—you will see three bolts holding the strut mount to the car body. Mark their position with tape or a marker so you can reinstall the strut in exactly the same spot. Remove all three bolts. The strut assembly will now be free and can be lifted out of the car.
Place the strut in a vise or find it firmly on a workbench. Attach the spring compressor tool to the spring according to the tool's instructions—typically you thread the compressor arms through the coils of the spring and tighten them evenly. Compress the spring slowly until there is no tension on the top mount. This usually takes 10 to 15 turns of the compressor handle, but go slowly and stop if you feel unusual resistance.
Once the spring is compressed, use a socket to remove the large center nut that holds the strut rod to the mount. Keep the strut rod from spinning by holding it with a wrench while you turn the nut. After the nut is off, carefully remove the mount, spring, and any rubber bushings. Keep all these parts in order so you can reuse them on the new strut if your kit does not include them.
Install the new strut and reassemble the top mount
Slide the spring and mount onto the new strut rod in the same order they came off the old one. Thread the center nut back on and tighten it firmly while holding the strut rod with a wrench. Do not over-tighten—snug is enough. Slowly release the spring compressor by turning the handle backward, watching the spring as it expands. Once the spring is fully extended and the compressor is loose, remove the tool.
Lift the new strut assembly into the car and align the three top bolts with the marks you made on the tower. Install and tighten all three bolts in a crisscross pattern (like tightening a wheel) to may support even pressure. Tighten them firmly but do not strip them.
Lower the strut so the bottom connects to the steering knuckle again. Install the two bolts that hold the strut to the knuckle and tighten them firmly. These bolts carry the weight of the car, so they need to be tight.
Reinstall the wheel and lower the car
Place the wheel back on the hub and thread the lug nuts by hand first to make sure they are going on straight. Tighten them in a star pattern (opposite sides alternately) to avoid warping the rotor. Raise the car slightly with the jack, remove the jack stand, and lower the car fully to the ground. Finish tightening the lug nuts with your socket set, using firm pressure but not maximum force—over-tightening can warp the rotor or strip the studs.
Repeat this entire process on the other side of the same axle. Do not drive the car until both sides are done, because uneven struts will make the car pull and handle poorly.
Check your work and schedule an alignment
Before driving, bounce each corner of the car by pushing down hard on the bumper. The car should bounce once or twice and then settle smoothly. If it bounces more than twice, the strut may not be seated correctly—stop and check that all bolts are tight and the spring is fully extended.
Drive slowly in a parking lot and listen for clunking or creaking from the strut area. If you hear noise, stop and check that the top mount bolts and bottom knuckle bolts are all tight. Once everything sounds and feels normal, schedule a wheel alignment at a shop within the next week. Strut replacement always changes the angle of your wheels, and driving on misaligned wheels will wear your tires unevenly and make the car pull to one side.
Frequently Asked Questions
Can I replace just one strut instead of both on the same axle?
No. Struts wear at the same rate, so replacing only one will cause the car to handle unevenly and pull to the side with the new strut. Always replace both front struts or both rear struts at the same time. Replacing front and rear at the same time is optional but recommended if both are worn.
What if I don't have a spring compressor tool?
Do not attempt the job without one. The spring is under extreme tension and will launch with enough force to cause serious injury. Rent a compressor from an auto parts store—most charge $20 to $40 for a day rental, and you can return it the next day. This is the safest and cheapest option.
How long does the job take?
Plan on three to four hours per side once you have all your tools and parts. The first side usually takes longer because you are learning the steps. The second side goes faster. If bolts are stuck or rusted, add extra time for penetrating oil to soak.
Do I need to bleed the brakes after replacing struts?
No. Strut replacement does not touch the brake system. However, if you disconnected any brake lines by accident, you would need to bleed the brakes. If you only removed the two bolts at the steering knuckle, the brakes are untouched.
What should I do if the top mount bolts won't come out?
Spray them with penetrating oil and wait 15 to 30 minutes. Try again with a socket and breaker bar for more leverage. If they still won't budge, you may need to drill them out, which requires a drill press or a trip to a shop. Avoid this by spraying bolts with penetrating oil before you start if your car is older than 10 years.