What do Shocks and Struts do?
Shock absorbers and struts do more than just provide a comfortable ride. Their most important function is to influence the control and handling characteristics of your vehicle. Without them, a vehicle would continually bounce and bound down the road, making driving extremely difficult. Shocks and struts are designed to help keep your tires on the road. They control the action of the spring to resist bottoming out . . . like when you hit a pothole . . . and keep the movement of the springs under control when they rebound.
How Shocks And Struts Work
Shocks provide resistance by forcing hydraulic fluid (oil) through valves in the piston as it moves up and down. Because the oil cannot be compressed, only a certain amount of fluid can be forced through these valves, which creates resistance to the vehicle movement. Premium shocks and struts are superior to regular hydraulic shocks because air in the shock is replaced by pressurized nitrogen gas. This advancement in technology prevents bubbles from forming in the hydraulic fluid. These bubbles, called foaming, reduces the ability of shocks to provide resistance and prevent bounce. Gas shocks also quicken the response of a shock's movement, thereby increasing comfort and control under all conditions.
How to Tell if Shocks and Struts Need Replacement
Under normal conditions, shocks and struts wear out gradually. However, many factors can affect how much wear is actually occurring and at what rate it is occurring. For example, two people buy the same vehicle new off the dealer lot . . . one lives in the city close to the office, and drives mostly on straight roads. The other lives in the country, 45 miles from the office and must travel 10 of those miles on a winding, often muddy gravel road. Because shocks operate in extremely hostile under-vehicle environment, where anything from gravel to ice and snow to grit can affect the life of the product, it is a good bet that driver #2 will need to replace his shocks long before driver #1. The piston rod can easily be nicked or damaged by flying gravel allowing grit and dirt to damage the piston seal. When this occurs, fluid begins to leak from the piston seal and eventually the shock will lose its ability to function properly.
Worn shocks and struts not only affect the ride comfort and control of your vehicle, but can affect its braking effectiveness, too.
Here is a good self test to check for signs of worn shocks or struts:
Do you experience excessive bounce (3 or more bounces) when crossing an intersection or dip?
When stopping quickly, does your vehicle rock back and forth several times?
While applying your brakes firmly at higher speeds, does your vehicle have a tendency to drift left or right?
When changing lanes quickly does your vehicle rock or sway from side to side?
On a tight curve like a freeway ramp, does your vehicle lean and sway giving it an uneasy and disconnected feeling?
Many components contribute to the handling characteristics of your vehicle. Having your vehicle inspected if you experience any of the above signs is good preventive maintenance and can help parts wear less and last longer. When inspecting shocks and struts, your service technician will look for:
A badly leaking shock or strut: The unit is losing fluid and can't provide the resistance for which it was originally designed.
Shiny Spots: at the contact point of the safety bumper. and marks between the coils of the spring called "coil clash." They are the result of topping and bottoming caused by excessive suspension travel.
Tire cupping: around the circumference of the tire can be caused by worn or ineffective shocks & struts.
Broken or loose shock or strut mount: The product is not solidly connected at both ends and cannot function properly.
Broken or damaged piston rod: The product cannot function properly and should be replaced.
So now that you've got the facts, wouldn't you agree that shocks and struts provide more than just a comfortable ride?
Courtesy of the Car Care Council
