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10004 Is it Time to Replace My Shocks & Struts?

Created on 2011-01-05 by Scott Hart

No matter what your handling objectives, your car's driveability depends on shock absorbers. The shocks perform their duties by keeping the spring rebound in check. Since shock absorbers have such a profound effect on ride control and stability, good shocks go hand in hand with driving safety.

There are a number of ways to determine if it's time for new shocks. The first is fairly subjective; if your car no longer rides as well as it used to; If it seems to bounce and drift more than you remember, or nose-dive when you brake, your shocks are probably worn out. An oil soaked shock indicates seal failure and must be replaced, however a light film of oil is normal. Torn or blown out mounting bushings can result in annoying clunks and rattles and the inability of the shock to perform as it was intended.

Generally speaking, a set of shocks can last around 50,000 to 60,000 miles, though this is by no means an absolute figure. Some shocks may last for only 30,000 or 40,000 miles, while others may still be functioning after 100,000 miles. Factors that affect this include how the car is driven and the conditions it is driven in. A car used predominantly for freeway commuting will have less wear on the shocks than one driven in stop-and-go traffic and on potholed surface streets. Likewise, if a car is driven off road frequently or on dirt roads or even rough roads, the shocks will experience more wear.  If an older car sits for a long time without being used, the shocks can sometimes freeze up and stop functioning. If you are going to start driving a car regularly that has been sitting unused for many years, you might have to install new shocks.

Another reason you may want to replace your shocks is if you want better performance from your car. As originally equipped, most cars have relatively compliant suspensions. By installing a set of high-performance shocks, you will improve the handling and sometimes even the ride quality.

The difference between a better shock and a bargain priced shock may not be visibly apparent, but when you consider the shock absorber's job, it's easy to see that shocks have to be built to withstand a great deal of punishment. As the name implies, they absorb the shock in your car's suspension. In so doing, they convert the energy of the spring into heat, and must be able to dissipate that heat efficiently in order to perform well. Most conventional shocks are of twin tube construction, and are less efficient at heat dissipation, which can cause poor performance. This means that when the road gets rough, a conventional shock will actually lose damping effectiveness. Add this to the slower response to changes in road surface, and you will see why many shocks offer a wallowing ride, with diminished stability and road holding qualities.

A shock that is made with monotube construction, such as Bilsteins are better able to stay cool over varying road surfaces and performance-oriented driving. Gas charged shocks use high-pressure nitrogen gas to maintain damping performance by preventing the shock oil from foaming. Using high-grade materials, and state of the art technology, the better shock absorber manufacturers confidently offer a lifetime warranty, making the best shocks a better bargain in the long run.

When replacing struts, pay close attention to the condition of the upper bearing plates. These support the weight of the vehicle, and are often in poor condition. A bad bearing plate can cause steering stiffness, noise and poor steering return (memory steer). Do not reuse the bearing plate or spring seat unless they are in perfect condition.

Installation Tips

In the case of front cartridges for MacPherson struts, special tools are required. Unless you've got both the tools and the skill, you may be better off  having  struts installed by a pro. Rear shocks are easier for the backyard mechanic to replace using  jack stands, and a few common tools. This is assuming rust and corrosion have not taken their toll. Use a liberal amount of your favorite penetrating oil (we use and recommend PB B'laster). On re-assembly, anti-seize compound will help keep these bolts free from corrosion.

Here‘s a quick recap of key things to look for if you wondering if the shocks and struts on your Volvo are in need of replacement. ..

  • A bouncy uncontrolled  ride, especially on rough roads
  • Your Volvo bobbing like a porpoise after encountering a speed bump or dip in the road
  • Excessive body lean or sway when cornering or driving in heavy crosswinds
  • Nose dive when braking
  • Tail squat when accelerating
  • Bottoming out the suspension on moderate bumps
  • Cupped wear on the tires
  • Noise or poor steering return when turning (front struts)
  • Wheel hop when braking on rough roads
  • Frequent activation of the ABS system when braking on rough roads

A car's shocks and struts have a tremendous impact on its ride and handling. Replacing the shocks and struts is a routine part of maintenance, though it isn't done as often as something like an oil change. There is no set time to replace shocks and struts, and deciding when to replace them is a based on how they feel on the road, as well as how many miles are on them.

Shocks and Struts, Testing "The Old Bumper Test"

For years it was not uncommon for shops, dealers and car owners to attempt to test shock and strut condition by jumping up and down on the front or rear bumper and watching to see how long it took the car to stop moving. We even used this method up into the 1980s until we saw a shock test being performed by a Bilstein technician. We were surprised at how fast the shock tester cycled the shock. Have you ever watched a gallon of paint on a paint shaker at the hardware store? He said that it is not uncommon for a car cruising at 60 mph to see the suspension move 1 full inch in 1/1000th of a second. The bumper test might be able to tell you if your shocks are completely blown out, but it won't tell you if they are still working safely. If you are unsure about the condition of your shocks, have an experienced technician at your Volvo dealer or independent repair shop take your car for a quick test drive. This is the safest way to determine the condition.


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