The MacPherson Strut
A MacPherson strut is a popular design for two main reasons: it’s cheap to manufacture, and it does not take up a lot of space. This is exceptionally important in any front wheel drive as more room is needed for the engine. A car’s suspension system consists of a variety of components; the ones that you have likely heard of the most are the struts. This is because they are typically replaced more often than the other components. The strut is the portion of the suspension system that serves to dampen the bound and rebound natures of a car that is travelling over bumps and/or around corners. The spring and the strut work together. The spring holds the vehicle up and provides the stability needed to keep the vehicle level while driving on the road. If the strut is completely worn and unable to provide any dampening forces at all, the car would be very bouncy. You could continue to drive a car like this however the springs are left to deal with quite a bit more force and might eventually break because the spring alone is not meant to deal with the type of forces that something like a pot hole could provide at higher speeds.
The way a typical strut works is by having a rod that slides in and out of the body of the strut. This sliding action is dampened by the controlled friction that occurs as a piston within the strut is dampened by a certain type of oil. The strut is a sealed unit; however, after time due to age, corrosion and general wear and tear on the seals that are used in the construction of the strut, the strut will fail. When you keep driving with failed struts, other parts start to wear more quickly. The spring is the first, the spring is holding up the vehicle and without the strut to back it up it is more susceptible to breakage. It will sag and let the car sit lower which causes the tires to wear on the inside much more quickly. You also might find that the car is scraping its tires on the inner wheel wells as the vehicle travels over bumps. The car will not handle as well when turning and this will put more stress on the suspension bushings and the sway bar end links.
The Complete Strut Assembly
The Complete Strut Assembly is available for certain models of cars that use the MacPherson strut suspensions. When replacing a bare strut in a vehicle, certain parts get reused. These parts are what make up the complete assembly. They include: the spring, upper strut mount / or bearing plate, the bump stop and the protective boot. Replacing the strut alone requires the reinstallation of all these used parts. Replacing the whole unit as a complete assembly drastically reduces the amount of work.
Complete strut assemblies are growing in popularity for manufacturers and consumers. Why replace the whole assembly when only the strut has failed? There are several reasons. The complete assembly typically costs twice as much if not more but may be able to save you money right away as well as further down the road.
Whether replacing these components yourself or paying a mechanic to do the work, advantages of using the complete assembly are seen immediately. No special tools are required. This makes the home job quite easy, there is no spring compressor required. At a shop you should typically see lower labor times; you might find that the extra money spent on the complete assembly is money saved from the reduced labor costs to install it.
Other advantages of installing the complete strut assembly on your vehicle are numerous. Getting a new spring is going to refresh your suspension and last longer than your old spring. This is because your old spring has sat under the weight of the vehicle for numerous years causing the spring to sag, corrode, and weaken over time. This causes your vehicle to sit slightly lower which changes the suspension geometry. Driving on a failed strut puts the spring to work even more as it is taking on all the forces of the road without the help of the strut to back it up. Other components of the complete assembly include the upper strut plate, bump stop and rubber boot. These are all components that wear out typically because of corrosion and dirt contamination. Replacing these components when tackling this kind of job is always a good idea; the failure of a small component like this shortly after the fact is a kick in the pants for obvious reasons.
The choice is clear when a complete assembly is available for your vehicle. The complete strut assembly is a money and time saving component. It is typically the most significant suspension part, and a great way to get your vehicle to ride like new.