Need Struts or Shocks ?

When struts and shock absorbers should be replaced

Shock absorbers and struts are parts of the vehicle suspension that absorb shocks from the bumps and potholes and keep your vehicle riding smooth and stable. What is the difference between a shock absorbers and a strut?

A strut is the shock absorber built into one unit with the coil spring. Any car has four struts/shock absorbers; one at each wheel. Most cars and SUVs have struts in the front suspension and shock absorbers or struts in the back.

Struts and shock absorbers are maintenance-free units. Does this mean that they never have to be replaced? A strut or a shock absorber doesn’t need to be replaced unless there is a problem with it or if you just want to upgrade your ride with new shock absorbers. The most common problem with shocks and struts is when they start leaking.  Struts and shock absorbers are filled with oil. If during a regular inspection, your mechanic noticed that a strut or shock absorber is leaking, it must be replaced, as it will stop working without a sufficient level of oil. Sometimes a shock absorber may stop functioning even without visible leaks.

What are the symptoms of a bad shock absorber or strut? Symptoms include bounciness and/or knocking when driving over bumps. You may also notice that your car swings up and down more, like a boat. To pinpoint a weak or failed strut or shock absorber, your mechanic may do a quick “bounce test” where each corner of the vehicle is pushed down and quickly released. The corner with the weak shock absorber will keep bouncing up and down longer, while the corner with the good unit will rebound slowly and will not bounce more than twice.

Another common reason to replace struts is after hitting a major pothole, curb or after an accident. In any of these cases, the strut might be bent, which may not be visible. Driving with a failed strut or shock absorber is not safe. In addition, if one shock or strut is not working, there is more load on the other three, which will cause them to fail sooner.

Do you have to replace both shock absorbers or struts if only one is bad? It’s not necessary, but it’s usually recommended to replace them in pairs, for example, both front struts or both rear shocks. This is because a new shock absorber will absorb road bumps better than the old one. If you replace only one shock absorber, it may create “unevenness” from side to side when driving over bumps. However, if your car is not very old, replacing only one strut or shock absorber may be enough, since the opposite side is not worn out yet.

Do coil springs need to be changed when replacing the struts? The answer is no: if the spring is in a good shape, it can be re-used with the new strut.

If one coil spring is bad, is it necessary to replace both? The answer is a bit tricky: coil spring sag over time, so if you put the new spring on one side and leave the old one on the other side, the side with the new spring may ride a bit higher than the opposite side. However, if your car is not very old and you are replacing the broken spring with the OEM part, it might be OK to replace just one. Of course, your mechanic might recommend replacing both springs to keep your suspension “even”, but again, it’s not necessary.

The cost to replace struts can run from $600 to $850 per pair. When struts are replaced, in most cases the wheel alignment must also be performed. The wheel alignment costs from $79.99. Replacing struts involves removing the coil springs that are under high tension. For this reason, it’s not something that can be easily done at home as a DIY project. It’s best to trust this job to your mechanic as most repair shops  have a special spring compressor tool that can safely assemble or disassemble a loaded strut.

- Jason Harris; Service Manager at Auto Aces Express

2666 N. Packerland Dr., Green Bay, WI., 54313; ( 920 ) 499 - 4424

" Your Problem Solved ! "

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Noisy Wheel Bearings ?

Signs of a worn wheel hub bearing vary in severity. Some may be difficult to detect, leading to damage before corrective action can be taken. The time frame in which damage occurs is linked to driving conditions and/or the mechanical practices that were followed at installation. Noise is a classic sign of a bad wheel bearing or wheel hub bearing. Here are some indicators of a worn wheel hub bearing or other wheel-end damage:

• Snapping, clicking or popping.

This can indicate a worn or damaged outer CV-joint. However, it also can be related to excessive bearing endplay, usually associated with inadequate clamping. This noise is typically heard when cornering or making sharp turns.

• Grinding when the vehicle is in motion.

Typically, this means there is mechanical damage in a wheel-end system. Related to a bearing, it means a loss of integrity such as roller or raceway damage. The noise is normally heard when turning or when there is a shift in load.

• Knocking or clunking.

This can signal excessive play in the CV-joints or U-joints. It also can be caused by excessive backlash in the differential gears. This is not generally associated with bearings and is normally heard either when shifting from changing directions, such as from forward to reverse or transitioning from accelerating to coasting.

• Humming, rumbling or growling.

These noises are normally associated with tire, electrical or drivetrain components. If bearing-related, the noise or vibration is present when driving in a straight line, but intensifies when turning the steering wheel slightly to the left or right. Typically, the side opposite the rumbling is the defective side.

• Wheel vibration and/or wobble.

This is generally associated with a damaged or worn tire, wheel or suspension component or severe chassis misalignment. When related to the hub or bearing, this normally indicates the loss of clamp or a bearing with extreme mechanical damage. It also can occur when lug nuts are not properly torqued.

• Shudder, shimmy or vibration at a constant speed.

This is normally associated with worn or damaged suspension components or tires that are out-of-balance or out-of-round. It is not normally indicative of hub or bearing damage.

• Abnormal side pull when brakes are applied.

This is normally indicative of a defective caliper or equalizer, but it also can be a sign of worn brakes or rotors. However, severe looseness related to a bearing can also cause excessive runout, which may cause the brakes to pulsate or pull. The most common cause is a warped rotor due to the caliper not retracting.

• Uneven rotor or brake pad wear.

This is normally indicative of a bad caliper and/or a bad equalizer, which is not bearing-related. Severe looseness related to a worn or damaged bearing can cause excessive runout, which can cause uneven wear on the brake pads and/or rotor. The most common cause is a warped rotor due to the caliper not retracting.

• Abnormal or uneven tire wear.

There are many causes of abnormal tire wear. The most common are worn or damaged suspension components, misalignment, improper inflation or tire selection. While extreme bearing wear or looseness can cause abnormal tire wear, it is typically related to other failure modes.

• ABS failure, which could be internal or external to the bearing or hub bearing assembly.

In extreme cases, internal and external sensors can be damaged from excessive movement caused by too much end-play. This indicates a lack or loss of bearing clamp. This normally results from severe mechanical break up or damage. (Additionally, in designs where the sensor is mounted externally, sensor damage can result from corrosion, stones and other hazards.)

- Jason Harris; Service Manager at Auto Aces Express

2666 N. Packerland Dr., Green Bay, WI., 54313; ( 920 ) 499 - 4424

" Your Problem Solved ! "

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