About Top Mounts
Top mounts are the unsung heroes of your car’s suspension system. They keep your drive smooth, quiet, and free from tire vibrations. However, they tend to be neglected due to their toughness to tear.
What is a Top Mount?
Top mounts are the top/hat of a strut hence the name strut mounts. They are sandwiched between the vehicle’s body and the suspension strut.
But what exactly is the function of a strut mount and why is it an integral unit of your suspension system.
Well, for better understanding, its best to start with the definition of a strut. A strut generally is an assembly of a spring coil and a shock absorber. It's mounted to the chassis of your car.
The spring coil is what is responsible for the height of your vehicle. It supports its weight and absorbs shocks from bumps. If compressed quickly (when you hit a bump at high speeds) it expands beyond its average height. The car's weight on the other end causes it to compress again starting the cycle over. The process repeats with the spring compressing and expanding at little less each time until the movement finally stops. This movement is what causes the bouncing effect on cars.
As a countermeasure, the shock absorber dampens vibrations from the spring by applying force in the opposite direction of their travel thereby slowing the motion. In short, shock absorbers prevent a ride that is bouncy and more importantly keep the wheels on the ground.
Your strut mount, on the other hand, acts as an insulator to your car's body. One end is bolted to the strut and the other to the vehicle. It cushions the strut's impact by reducing the jarring effect, vibration, and noise that could be transferred to your car's body.
You top mount also protects your suspension strut from jamming up from the occasional force acting between the spring and the shock absorber.
Top Mount Construction
Today’s vehicles feature a top mount made of solid rubber with a metallic ring between. The toughness of the rubber is paramount; if too hard, your car’s comfort is compromised. But then again, if too slack, it tends to wear out fast.
The top mount consists of two or three parts depending on whether it's for the front or rear suspension strut. They include the mounting plate, upper strut bushing, and an optional upper strut bearing (featured in front suspension struts of front-wheel drive and all 4WD wheels).
While the mounting plate and bushing act as buffers, your strut bearing enables the stationary top mount assembly to rotate accordingly when driving. If damaged, it will force the whole strut mount to twist with the wheel. The repercussions are significant as the twisting and turning causes premature damage to your car spring.
Instead of the default rubber bushing, you can switch to a pillow ball mount that features spherical metal bearing. The tradeoff would be a noisier ride with less comfort however improved performance, and adjustment options is a plus that comes with it.
Different Types of Top Mounts
There are two types of strut mounts: front and rear top mounts. Front struts mounts feature bearing plates that act as steering pivots and as such, they critically affect the steering movement, response, and smoothness. Four-wheel-drives however, feature strut bearing on all wheels.
How to tell if your Top Mounts are damaged?
Some signs act as indicators for damaged top mounts. They include:
- Clunking noises when driving
- Cracks and tears on your rubber top mount or sagging rubber
- The steel ring detaching from the rubber casing
- Hard steering especially on bends
- Tire wear
- Car vibrations
- Wrong tire alignment
How your Top Mounts get Damaged
Your strut mounts as recalled earlier are under constant pressure between the car's body and the underlining suspension system. The heavy vibration over time may lead to their degradation. However, certain lousy driving habits may quicken the wear out process. This includes:
- Continually driving on adverse road conditions: Such hardy vehicles need a regular top mount checkup. Ideally after 12,000 miles its best to go in for a checkup and replace your strut mount once it passes the limit of 60,000 miles.
- Wrong alignment during replacement: When replacing your worn-out struts with new ones, it’s crucial to be keen on the alignment as wrong connections would not only affect the lifeline of the top mount but also tamper with the suspension system.
- Using the wrong top mount:
As simple as it may sound, a wrong top mount can drastically affect the performance of your vehicle. Be sure to choose the right suspension top mounts that correspond with the suspension strut and the manufacturer’s requirements.
Replacing your Top Mounts
Top mounts rarely get worn out. If well maintained, they can serve you throughout the lifeline of your vehicle. However, if you are replacing the strut with a new one, it’s better to change the top mount as well. Always remember to replace your suspension top mounts in pairs.