This is a question every technician has heard after recommending replacement of the MacPherson struts and/or shock absorbers on a vehicle. This recommendation is usually made based on a visual inspection of the truck, SUV or car suspension components (the struts and shocks in this instance).
Mileage: most manufacturers of shocks and struts suggest a close inspection after the average vehicle has been driven 50,000 miles.
Of course, the type and condition of roads driven, coupled with the driving style of the principle driver, will determine how long these parts will perform satisfactorily.
During the inspection, the technician will be looking for signs of fluid leaks that indicate one reason to recommend replacement. He will also look at how the tires are wearing.
Briefly, here's a technical explanation of struts and shocks.
These parts are designed to control the tires, to keep them in contact with the road surface as much as possible. If vehicle tires are free to bounce (which is what happens when struts and shocks wear) they are not as effective at gripping the road, so steering, handling, and braking are all affected. Shocks and struts are not just for ride comfort: their primary function, tire control, is a much more important role.
A Gradual Deterioration of Struts and Shocks
Because the wear of these components is mostly internal and cannot be seen like worn tires or brake pads, and because it is very gradual, the everyday driver is the last to notice the difference. A passenger riding in the vehicle for the first time may even comment on the “ride” that seems normal to the driver. But, regardless of how it may feel to you, worn struts and shocks will cause a change in tire wear and vehicle handling that should not go unaddressed.
Enjoy benefits of replacing worn shocks and struts.
Replacing these worn components will restore the ride control and handling the vehicle demonstrated when it was new. It also means longer tire wear. New shocks and struts also help reduce potential wear of other steering and truck, SUV or car suspension components.
Finally, replace your struts and shocks in pairs.
Shocks and struts should always be replaced in pairs or, better yet, all four, for even, predictable handling and control. After all, all four have been on the vehicle for the same number of miles and worked under the same conditions. Remember, too, that whenever the struts are replaced, it becomes important to check the alignment, as it may have changed, to protect your vehicle tires and assure maximum safety.