What are struts and mounts?
Your car bounces uncontrollably and rattles over every bump. You feel every vibration in the steering wheel. You likely have worn-out suspension components that need immediate attention.
Struts are the main shock absorbers in a MacPherson suspension system, while strut mounts are the rubber-insulated anchors that bolt the struts to the vehicle’s chassis. Together, they dampen road impact, support vehicle weight, and allow the wheels to turn smoothly.
Understanding the difference between these two parts is vital for fixing your ride quality, as replacing one often requires replacing the other to ensure a complete repair.
What are strut mounts?
You hear mechanics mention "mounts" during a shock replacement quote. You wonder if they are just trying to upsell you unnecessary parts for your vehicle.
A strut mount is a sandwich of metal and rubber that acts as the interface between the suspension strut and the car body. It insulates the cabin from road noise and often contains a bearing to allow the steering to rotate.
I spend a lot of time on the GSW Autoparts manufacturing floor observing how we bond rubber to metal. It is a fascinating process. The strut mount looks simple, like a heavy coaster, but it is an engineering marvel. It has to support the weight of the car while blocking noise.
The strut itself handles the big bumps—the potholes and speed bumps. But the strut mount handles the "buzz." As your tires roll over asphalt, they create high-frequency vibrations. If the strut was bolted directly to the metal frame of your car without a mount, your teeth would chatter as you drove. The rubber in the mount absorbs that energy.
For front suspensions, the mount is even more complex. It usually houses a bearing. Since the front wheels steer, the strut has to turn. The mount stays bolted to the car, but the bearing inside allows the strut to spin underneath it. Without this, your steering would bind and snap back.
Here is a breakdown of the components:
| Part | Role | What happens if it fails |
|---|---|---|
| Mounting Plate | Bolts to the car tower. | Metal fatigue or rust issues. |
| Rubber Insulator | Absorbs vibration. | Cracking leads to clunking noises. |
| Bearing (Front) | Allows rotation. | Steering becomes stiff or makes popping sounds. |
How to fix strut mount noise?
A constant clunking or squeaking drives you crazy every time you drive. You want to stop the noise without spending a fortune on the wrong repairs.
To fix strut mount noise, you must verify if the rubber is torn or the bearing is seized, then replace the entire mount assembly. Lubricating an old mount is a temporary patch; replacement is the only permanent solution.
I recall a customer, a taxi fleet owner, who tried to save money by spraying heavy grease into his worn-out mounts. He thought the squeak was just dry rubber. It worked for about two days. Then the grease attracted dirt, which acted like sandpaper, grinding the bearing down even faster. The noise came back louder than before.
The only way to truly fix the noise is replacement. You have to remove the strut assembly from the car. This involves compressing the powerful coil spring—a dangerous job if you do not have the right tools. Once the spring tension is off, you remove the top nut and swap the old mount for a new one.
At GSW Autoparts, we always recommend checking the "seat" where the spring sits. Sometimes the noise is not the mount itself, but the rubber insulator pad that the spring sits on. If that pad wears through, you get metal-on-metal contact.
Steps to silence the noise:
- Identify: Is it a "clunk" (collapsed rubber) or a "creak" (seized bearing)?
- Remove: Take the strut out of the car.
- Inspect: Look for cracks in the rubber or rust in the bearing.
- Replace: Install a high-quality mount with fresh rubber.
- Align: Always perform a wheel alignment after reinstallation.
How do I know if the strut/shock mount is damaged?
You suspect your suspension is failing but do not know the signs. You need a clear checklist to diagnose the problem before it causes safety issues.
Signs of damage include clunking noises over bumps, visible cracks in the rubber under the hood, excessive vibration in the steering wheel, and the center strut bolt sitting off-center or pushed up.
Visual inspection is your best friend here. Open your hood. Look at the strut towers (the metal domes on the left and right fenders). You will see the top of the mount. If the rubber looks like dried mud—cracked, crumbling, or separated from the metal—it is toast.
I have seen cases where the rubber failed so badly that the center metal sleeve tore free. When the driver hit a bump, the strut shaft actually pushed up and dented the hood of the car. That is an extreme case, but it happens.
Another test involves the steering. Park the car and have a friend turn the wheel. Listen near the fender. If you hear a "pop" or a "binding" sound, the bearing inside the mount is likely seized. The spring is building up tension and then snapping free, rather than turning smoothly.
Diagnostic Checklist:
| Symptom | Meaning |
|---|---|
| Hollow Clunk | The rubber has collapsed; metal is hitting metal. |
| Steering Bind | The bearing is seized or rusted. |
| Vibration | The rubber has hardened and no longer insulates. |
| Visual Gap | The mount has separated; immediate replacement needed. |
Why replace Strut Mounts?
You are replacing your old shocks and want to save money. You consider reusing the old mounts to keep the total repair bill down.
You should replace strut mounts because the rubber degrades over time just like the shock absorbers. Reusing old mounts leads to vibration, poor alignment, and paying for double labor when they fail shortly after the new struts are installed.
This is the most common conversation I have with our wholesale partners. They ask, "Can we just sell the bare strut?" I tell them, "You can, but your customer will be back in a month complaining about noise."
Think about the labor cost. To replace a strut, a mechanic has to remove the wheel, disconnect the brakes, unbolt the suspension, and disassemble the unit. That takes 2 to 3 hours. To replace the mount, they have to do the exact same steps.
If you pay $300 in labor to install new shocks but reuse a $30 old mount, you are taking a gamble. If that old mount fails two months later (which is likely, since it was disturbed during the repair), you have to pay that $300 labor fee all over again just to change the cheap part.
Furthermore, worn mounts affect safety. If the rubber is loose, your wheel alignment1 shifts as you drive. This reduces tire contact with the road, increasing your braking distance2. At GSW Autoparts, we see this data in our testing. A car with new shocks but bad mounts still stops slower than a car with everything new.
Benefits of replacing them:
- Protection: New mounts cushion the new shocks, helping them last longer.
- Cost: It is cheaper to do it once than to do it twice.
- Comfort: Restores that "new car" silence and smoothness.
- Safety: Ensures accurate steering response and braking.
Conclusion
Struts and mounts work together to provide a safe ride. Always replace them in pairs to ensure your vehicle handles correctly and to avoid paying for labor twice.
About the Author
Root is a Content & Operations Specialist at GSWAUTOPARTS with 5 years of industry experience. Leveraging his close proximity to our manufacturing floor, Root specializes in documenting product details and production processes. He focuses on translating technical insights about rubber and chassis parts into clear, helpful information for our customers.
