Diagnosing Car Suspension Problems

1 How Does A Car Suspension System Work?

The suspension system of a car mainly comprises shocks, struts, leaf springs, coil springs, and control arms. The shocks and struts stabilize your vehicle’s movements and offer better control when you turn, brake, accelerate, or drive over uneven road surfaces. Most vehicles today use shocks, struts, or a combination of both. The basic difference between a shock absorber and a strut is that a shock absorber is an independent component, while the strut combines the shock and other features in a single structural unit. Shock absorbers and struts are designed to dampen the compression and rebound of the springs and help stabilize the vehicle and keep the tires in contact with the pavement.

The most famous strut is the MacPherson strut used today on almost all front wheel drive cars. These independent type suspensions are very famous on passenger cars because they are simple in construction and eliminate the use of two control arms, unlike double-wishbone suspensions. Suspension design and working can also vary based on different applications. For a sedan or a family vehicle, MacPherson struts are used, but for a racing vehicle or a sports car, suspensions are designed specifically to meet the requirements. Similarly, different types of off-road suspension systems are used on SUVs, trucks, and off-road vehicles. Suspension plays a vital role in the car’s handling‌‌ therefore, it’s necessary to diagnose them to ensure they are functioning properly.

2 Tips To Diagnose Your Shocks And Struts

Worn out or failing suspension components like struts or shocks are easy to identify. The most common symptom of a bad suspension system is when the vehicle squats or dives during acceleration or braking. Other sign of a bad shock or strut includes excessive bounce, leaking suspension fluid, vehicle swaying sideways or instability at high speeds. However, one gets used to the way the car performs because the suspension gets damaged gradually, keeping you unaware of the wear and tear with the suspension. If you suspect there is a problem with your suspension system, follow the 5 step diagnosis procedure below.

Take A Test Drive

A test drive is the best way to look for any problems associated with the vehicle’s performance, handling, and control. As we know, suspension and steering are interconnected systems, problems with the steering system can affect the suspension system and vice versa. For example, a weak shock absorber cannot dampen bumps and shocks, allowing excessive feedback through the steering linkage to the steering wheel and the driver. The driver may diagnose this as a steering problem while the real problem is in the suspension system. Also, a bad upper bearing on the front struts can cause your steering to feel stiff and difficult to turn.

Therefore, a good way to ensure the suspension is working fine is to accelerate hard and brake hard to check if the vehicle squats and dives. A squat is a condition when the rear of your vehicle dives down while accelerating the vehicle and front dive is when the front end of a car dives significantly when the brakes are applied. Also, perform sharp turns to note down any excessive roll or sway in the vehicle. Any excessive bounce, roll and sway, brake dive, or acceleration squat could be an indication of bad shock or strut.

Here is a checklist that you must have while taking a test drive rate these on a scale of 1 to 10.

• Rate the ride on a rough road and how suspension takes tar strips and bumps?
• Note down the steering feel after hitting a bump. Mark the steering effort and return feel, if it feels sticky, jerky, or harsh.
• Rate the body lean or sway when cornering.
• Mark the vehicle nose dive when you hit the brakes and squat when accelerating.
• Note down any unusual noises such as squeaks, rattles, or clunks.

Perform A Car Bounce Test For Shocks And Struts

To perform a bounce test, push down your car at all four corners (front right, front left, rear right, and rear left) to check how the suspension responds. The car should bounce up, and then settle back to its original height quickly. If the car bounces more than twice or keeps on moving up and down, it’s most likely that you need new shocks. A shock absorber with good damping will allow the vehicle to rest back to its original condition just after you let go of the suspension. A sign of a bad strut or shock absorber is a bouncy suspension and an uncomfortable ride over bumps and rough roads.

Inspect The Tires For Abnormal Wear

Inspect the tires for any kind of unusual wear patterns on treads. Any indication of uneven tread wear, or ply separation, can be a result of worn-out strut and shock. Although proper tire maintenance and care is necessary to ensure they last a long time, suspension related problems can lead to uneven wear. If you rotate your tires at recommended intervals, your tires should wear out evenly. However, uneven wear can occur due to bad camber settings that can be caused by worn out suspension components. It’s necessary to keep your wheels aligned because a negative camber or positive camber beyond recommended intervals can cause your tires to wear out from one side.

Vehicle Ride Height Inspection

A common symptom of a bad suspension is decreased or uneven height of the vehicle. It’s easy to check the ride height of your vehicle by using a measuring tape. Park your vehicle on a leveled ground to measure and compare ride height at all four wheels. Take a tape measure or a ruler and measure the distance between the top of your wheel and the bottom of the wheel well or the fender. Measure the length near all the wheels of your vehicle and check if there’s a difference. A light variation of half an inch in the measurements is fine, but a major difference indicates an issue with the suspension system. If the measurement on one side differs a lot, the suspension might be faulty. A difference of more than half inches from side to side indicates weak springs or another suspension problem. Also, compare the vehicle’s measured ride height to the specified height in the manual. If the ride height is less than the lower-limit mentioned in the specifications, the springs may be sagging and need to be replaced.

Inspect The Strut Mount

A defective upper strut mount can cause noise, steering binding, or allow the upper end of the strut to change its position, affecting wheel alignment angles. Strut mount inspection should start with a road test checking for any unusual noise, pulling, or steering binding. This can be done by rotating the steering wheel from stop to stop. Noise or binding could indicate a defective bearing. Also, inspect the rubber portions of the strut mount for cracks or separation of the rubber from the steel. Note the position of the strut piston rod and raise the vehicle on a hoist. Note any change in the position of the mounting assembly. A slight downward movement is normal, but any side-to-side movement could indicate a defective mount.

To inspect your strut mount further, lift the wheels off the ground, grip the coil spring as close to the upper strut mount and push it in and out on the strut. Watch for movement of the upper end of the strut piston rod and ensure there should is no free movement. If there is excessive movement, the upper strut mount should be replaced. Complete the inspection after removing the upper strut mount from the strut assembly. The steering pivot bearing should be checked to ensure smooth and free rotation. Make sure the rubber portion has no excessive cracking or breakage. If you see any signs of major damage, replace your strut assembly to ensure a perfectly functioning suspension system.

Perform A Visual Inspection

Visually inspect the struts and shocks for cracks in springs, rubber pars, shafts, bolts, or any leakage of fluid from the shocks. It’s important to remember that shocks and struts are hydraulic systems and any leakage of fluid indicates the possible need for replacement. Also, inspect the grease boots and rubber bushings that keep the parts lubricated and prevent direct metal-to-metal contact. The bushings can get damaged and break apart with time and have to be replaced. Cracks or tears in control arm bushings are very common suspension-related problems that often go unnoticed. Replace your control arm bushings with new ones or long-lasting polyurethane bushings to ensure a smooth suspension system.

3 What Happens If You Drive On Bad Shocks Or Struts?

Driving on bad shocks or struts not only affects other components of your vehicle adversely but also poses a risk of a catastrophic failure and, in worse cases, an accident. Bad shocks and struts, lead to vibrations in your vehicle and can cause your vehicle to perform abruptly while driving over bumps and rough roads. Bad suspensions can also cause excessive or uneven wear on your tires, decreasing their life and leading to high repair costs. They also affect your vehicle’s braking because they absorb the weight of the car as it comes to a stop. When they wear out, the struts can’t do their job properly, resulting in extra stress on the brake pads and rotors, causing them to wear out faster. A vibrating steering wheel is a common sign that indicates a potential problem with the brakes or struts. A failing suspension makes the driving experience worse and handling tough while cornering on uneven roads. Your car might sway and won’t be as responsive when you turn the wheel, making you feel like it’s being pulled in another direction while turning. This can even lead to a major accident posing a threat to the life of the passengers.

Checking your car’s suspension system is necessary to ensure a good and safe ride. After diagnosing the suspension system of your vehicle, if you believe one or more components are damaged, we highly recommend you consult a professional mechanic. However, replacing the suspensions of your vehicle is easy. To ensure a long-lasting and efficient performance, it is necessary to choose a correct suspension system designed for your vehicle and your requirements. If you are an avid off-roading enthusiast, choosing the correct 4×4 suspension for your truck is important. Refer to our ultimate suspension buying guide for more insights into the best suspension system so you can make an informed decision while choosing one for your vehicle.