Home CAR GUIDE How to Check Car Shock Absorber

How to Check Car Shock Absorber

A shocker is a suspension component that is responsible for controlling the up-and-down motion of a vehicle’s wheels. Though the devices provide some shock absorption, the job of absorbing shocks is handled usually by the springs. More accurately called dampers, “shocks” damp excessive motion which keeps the vehicle’s body from bouncing down the road.

Cars with worn-out shock absorbers illustrate the devices’ purpose because they tend to bounce continuously. Worn-out shocks compromise a car’s road holding as well as braking. The bounce test is a time-honored method for checking shock-absorber health, but mechanics may also spot oil leaking from the shock, which means the component is starting to fail and should be replaced. Uneven tire wear is yet another sign of shock failure.

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In a vehicle, shock absorbers reduce the effect of traveling over rough ground which leading to improved ride quality and vehicle handling. While shock absorbers serve the purpose of limiting excessive suspension movement, their intended sole purpose is of dampening spring oscillations. Shock absorbers use valving of oil and gasses to absorb excess energy from the springs. Spring rates are chosen by the manufacturer which are based on the weight of the vehicle, loaded and unloaded. Some people utilize shocks to modify spring rates but this is not the correct use. Along with hysteresis in the tire itself, they dump the energy stored in the motion of the unsprung weight up and down. Effective wheel bounce damping might require tuning shocks to an optimal resistance.

Spring-based shock absorbers usually use coil springs or leaf springs, though torsion bars are used in torsional shocks as well. Ideal springs alone, however, are not shock absorbers, as springs only store and do not dissipate or absorb any energy. Vehicles mostly employ both hydraulic shock absorbers and springs or torsion bars. In this combination, “shock absorber” refers specifically to the hydraulic piston that absorbs as well as dissipates vibration. Now, the composite suspension system is used mainly in two-wheelers and leaf spring are made up of composite material in four wheelers too.

Video of What are Shock Absorbers and How do they Work

Symptoms of a Bad or Damaged Shock Absorber

Here are a few things that can go wrong with your shock absorbers:

1. Fluid Leaks

Leaks are generally the earliest indicators of a problem. If the seals surrounding the shock’s shaft start to leak, the fluid will run down the side of the shock towards the ground. If you notice any fluid leak from the shocks or struts, you should check to see if the bodies are dented (or otherwise physically damaged), and examine the bushings for corrosion or other damaged.

2. Tire Wear

A worn shock is unable to keep the tire firm on the surface of the road. The part of the tire that is coming in contact with the road will wear but the part of the tire that is not in contact with the road will not, leading to uneven tire wear. If your tires are unevenly worn or are showing abnormal flat areas, you need to investigate the cause.

3. Excessive Bouncing

If you drive over a big bump, pothole, or a patch of rough road and your vehicle still continues to bounce, your car might need a shock or strut replacement.

4. Front Nose Diving

If the front end of your vehicle (otherwise known as the nose of your car) dives towards the ground when braking, your shocks and struts have to be replaced or at least evaluated.

You might also feel that it takes extra time for the vehicle to stop. This happens when the shock is struggling to take up all the piston rod length and, in turn, extending the stopping distance required to come to a complete stop.

5. Rear Squatting

Another common sign that your shocks or struts are in need of service is if the rear end of your vehicle “squats” towards the ground as you accelerate. Additionally, if you make a turn and the vehicle is dipping drastically to one side, your shocks or struts might need to be replaced.

6. Instability at High Speeds

And as it wears, the suspension might not perform as well as it originally did. You might notice less control when steering, that the car wanders slightly from side to side, increased bouncing, or “nose-diving” when braking. All of these symptoms indicate a serious problem.

Video of Top Ten Signs of Worn Shocks and Struts

How to Replace a Shock Absorber

A) Lifting and supporting your vehicle

Materials Required

  • Floor Jack
  • Jack stands
  • Replacement shock absorber
  • Sockets
  • Ratchet
  • Wheel Chocks
  • Wheel blocks
  • Wrenches (box/open-end)

Step 1- Chock the wheels.

Put wheel chocks and blocks in front and behind at least one tire at the opposite end of the vehicle from where you are working.

Step 2- Raise the vehicle.

Jack the vehicle up from the appropriate jacking points or from a strong frame/uni-body location.

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Note: Make sure the floor jack and jack stands are of the correct lifting capacity for your vehicle. See your vehicle’s VIN tag for the GVWR (Gross Vehicle Weight Rating) if you are not sure.

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Step 3- Place the jack stands.

•    Just like jacking the vehicle up, place the jack stands at a strong chassis point to support the vehicle. Once placed, then slowly lower the vehicle onto the stands.

•    Move the floor jack for supporting the suspension under each corner as you’re replacing the shocks because the suspension will drop down a bit when you remove the shock.

B) Remove and install shocks

Note

•    Replacing front, as well as rear shocks, are pretty much the same process with a couple of exceptions. Access to the lower shock bolts is usually from under the vehicle. The top bolts for the front shocks can mostly be accessed under the hood. Rear shocks can be accessed from the under the vehicles.

•    With others, the top mounts are sometimes accessed from inside the vehicle in areas like the rear parcel shelf or in the trunk. Verify your shock mounting points before starting.

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Step 1- Remove the upper shock bolt.

Removing the upper shock bolt first makes it easier in sliding the shock out from the bottom.

Step 2- Remove the lower shock bolt.

By removing the upper shock bolt first, you can now lower the shock out of the bottom of the vehicle. Otherwise, it would drop out if you just remove the bottom bolt before the top.

Step 3- Install the new shock.

From under the vehicle, you need to push the upper part of the shock into its upper mount. Have someone to help you secure the shock bolt into the upper mount as you are pushing it up.

Tip: The shocks are usually packaged in the compressed position, held by a plastic strap. The gas charge in the shocks can make them difficult to compress through the hand. Leaving that strap in place till you secure the upper mount usually makes installation easier. Cut it off once you have secured the top shock bolt.

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Step 4- Install the lower shock bolt.

Once you have aligned the shock to the suspension mounting, you need to secure the lower shock bolt.

Note: If you are replacing all four shocks, there’s no order that you need to follow. Change the front first or rear first if you want to. Jacking and supporting the vehicle is the same, whether at front or rear. But always replace them in the form of pairs.

Video of How to Replace Shock Absorbers

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