Strut Mount Replacement – When to Do It With New Struts

Posted by

admin

When the shop quotes a strut replacement, it usually asks whether you want the mounts replaced at the same time. The mounts are a small part of the total bill, but skipping them means the strut has to come out again in a year or two when the mount wears. The labor overlap makes it the cheapest time to replace the mounts, and most experts recommend doing them every time the struts are off.

What the driver feels

The original struts have over 80,000 miles.
A clunk over bumps that has gotten worse.
A click when turning the steering wheel at low speed.
Cracked or hardened rubber visible at the strut tower.
Vibration through the steering wheel.
Uneven tire wear on the front.
A slight wander on the highway.
Fluid weeping on the strut body.

Why replace them together

The strut mount has to come off when the strut is replaced. On a Toyota RAV4 or Honda CR-V, the strut assembly comes out of the car, the spring is compressed, and the top mount unbolts. If you are already paying the shop to do that work, adding a new mount costs only the part price, because the labor is already included. Doing the mount separately later means paying the full labor again.

The original mount is usually worn at the same mileage as the strut. On a Ford Explorer or Jeep Grand Cherokee, the rubber mount hardens after 80,000 to 100,000 miles, the same mileage the strut cartridge wears out. Reusing the old mount on a new strut means the new strut is bolted to a tired, cracked rubber bushing, which transmits vibration and clunks into the cabin. The new strut feels worse than it should.

Inspecting the old mount

When the strut is out, inspect the old mount: check for cracks in the rubber, play in the bearing, and separation from the metal plate.
If the rubber is still soft and pliable and the bearing turns smoothly, reusing it is acceptable on a low-mileage car.
If the rubber is hard, cracked or compressed, replace the mount.
Check the bellows boot and bump stop at the same time, because they are cheap and should be replaced when the strut is apart.
Compare the old mount to the new one: if the old one looks visibly compressed, it is worn.
Safety note: The spring is still compressed when the strut is out. Keep the compressor clips in place and never put your face near the spring.
Torque the new mount nut to specification, but only after the car is back on the ground at ride height.
Replace both mounts on the same axle, even if only one looks worn.

What to replace with the struts

Replace the strut mounts every time you replace the struts, because the labor overlap makes it cheap.
Replace the bellows boot and bump stop at the same time, because they protect the new strut seal.
If the coil springs have sagged, replace them at the same time as well.
Choose OE-quality rubber mounts, because cheap poly mounts transmit more road noise.
After the job, align the front end and test the steering for the mount click.