Do Strut Mounts Need to Be Replaced in Pairs?

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A clunk on one side of the front end leads the driver to think only that strut mount needs replacement. The other side looks fine and costs less to leave alone. But strut mounts on the same axle wear at nearly the same rate, and replacing just one creates an unbalanced feel and a second repair within months. The cost of the second mount is small compared to the labor of doing the job twice.

What the driver feels

One side clunks over bumps while the other feels quiet.
The car leans slightly more to one side in corners.
One front tire shows slightly more shoulder wear.
The bounce test settles differently left versus right.
The steering wheel clicks more in one direction than the other.
A slight pull to one side on the highway.
Cracked rubber visible on one mount but not the other.
A noise that appears only when turning toward one side.

Why pairing matters

Strut mounts on the same axle see the same mileage and road conditions. On a Honda Civic or Toyota Corolla, both left and right mounts go through the same heat cycles, the same potholes and the same steering inputs. When one develops a crack or a worn bearing, the other is close behind. The visible difference is often just luck: one hit a few more potholes on the driver side.

Replacing only one mount creates an asymmetry. On a Ford F-150 or Chevrolet Silverado, the new mount on one side is firm and quiet, while the old mount on the other side still clunks and vibrates. The driver still hears the noise, just on the other side, and brings the car back for the second mount. The second repair costs the same labor as the first, so the total bill is nearly double what a pair would have cost.

When single replacement is acceptable

Inspect both mounts on the same axle: if both are over 80,000 miles, both are worn even if only one clunks.
Compare the rubber: if both are hard and cracked, replace both.
Consider whether one mount was recently replaced after a collision, in which case only the older one needs service.
Check the mileage: under 40,000 miles, a single mount replacement after a pothole hit is acceptable.
Compare the steering click: if the click appears equally in both directions, both bearings are worn.
Safety note: Never replace just one strut mount on a car that will be driven on the highway, because the asymmetry affects steering feel and alignment.
After replacing a pair, align the front end to confirm both sides sit evenly.
If you do replace only one, plan to do the other side within a year.

Pairing recommendations

Replace strut mounts in pairs on the same axle, even if only one side seems noisy.
If the struts are also worn, replace the whole strut assembly pair with new mounts included.
Match the mount brand left to right, because a premium mount on one side and an economy one on the other creates an uneven feel.
If one side was just replaced under warranty and the other is original, replace the original one too.
After the repair, test the steering left and right and the bounce test on both sides.