In this brief article we are going to discuss how to diagnose suspension problems that are common in most cars, and troubleshooting tips on maintenance.
What are the Most common suspension issues that you could easily diagnose?
- Clunking sounds from the front/rear suspensionBouncy suspension
- Bumping/Knocking Noises when steering
- Bouncy and Squeaky suspension
- Knocking noises while normal driving
- Poor Handling; uneven Tire wear
- Suspension warning message
Clunking sounds from the front/rear suspension
- If the noise increases on a rough road, it is a sign that points to an issue with the Anti-roll bar(ARB) links
- The anti roll bar does not articulate so much on smoother surfaces and hence is less noisy
- An easy way to check the ARB linkages is to hold each link and shake it by hand observing for movement or noise at each linkage point.
- You could also use a pry bar for better leverage and accessibility
- There are 2 potential causes within the Anti Roll bar assembly
- Anti roll bar Subframe mounting bush failure, and
- Anti-roll bar End link Failure
- The Anti-Roll bar (ARB) bushings are the isolators between the ARB and the vehicle’s chassis. The bushings also ‘secure’ the ARB in place and restrict excessive movement so that the ARB can properly function
- The ARB is under torsional loads while the car is undergoing “Roll” motion either during cornering or Rough Roads.
- In these situations, when the ARB undergoes torsion, the mounting bushes also share part of the road loads.
- Bushings that have aged, hardened, or simply worn out and become loose tend to cause noise as they allow unnecessary movement of the ARB.
Bumping/Knocking Noises when steering
- The Top Strut Mount contains a Bushing as well as a bearing that allows the strut to rotate while steering
- Generally, when the Top Strut mount is damaged, both the bushing as well as the bearing fail and restricts the strut from rotation during steering.
- The bearing failure causes the knock and creak noises while locking the steering.
- The Bushing failure causes the Knocking and Popping noises driving over a rough patch.
- The Strut Top Mount is assembled with the Front Shock Absorber Strut. So for removing this, you would need to disassemble the Front Strut.
Bouncy and Squeaky suspension
- In some vehicle the same problem might appear as Knocking and Popping Noises from the Front/Rear while driving over bumps
- The Bouncy Ride symptom points to the Shock Absorber as a probable cause.
- The noises coming from the suspension are partly due to the failed shock absorber allowing the bump stops to contact more often. And also the noises partly come from the worn out shock mounting bushes that allow the shock to move and hit against the mounting brackets.
- If your vehicle has crossed 40-50K miles, then it could be due for a shock replacement. Due to long-term internal wear, the shock absorber starts losing its damping action over time.
- If the shock absorber has started leaking oil due to a failed oil-seal, then it means that the shock will no longer be effective.
- One good way to tell if your shock has failed or not is to do a “Bounce Test”. Put all your weight on one of the front corners of the vehicle pushing it downwards. Keep oscillating the corner till you feel that it has reached its maximum height. Once you take your hands off the corner, observe how it settles. If it takes more than 2 oscillations to settle, that means the damper has failed.
Knocking noises while normal driving
- Knocking Noises while driving on a normal road and over Rough Patches
- The lower control arm ball-joints are also subject to wear and tear.
- The deterioration is usually initiated as a crack or rupture in the rubber boot around the ball-joint
- This leads to loss of lubrication and finally to complete wear out
- The wear out causes play or movement accompanied by knocking noise. The play in the ball-joint is one of the reasons for the vehicle steering feeling value
- You can easily check for Ball-joint condition by this simple procedure:
- Get the car on a Ramp
- Lock the steering wheel
- Hold the front tire with both your hands in a 6 o’clock position and try to move the wheel vertical up and down
- If you hear a ‘Knock’ or ‘Click’, then it is very much likely that the noise is due to a play in the Ball-joint
- Due to the worn out ball-joint, the Lower control arm is now having play at the bushing and ball-joint locations and therefore the lower arm is not anchored to the subframe properly. The ball-joint play also leads to wheel wobble. Poor handling of the car is due to these factors
Poor Handling; uneven Tire wear
- From the presence of a Tire wear issue, it can be inferred that the alignment of the front suspension is outside of the recommended settings. But this is still a symptom.
- The cause for the change in alignment is closely related to the Lower control arm Bushings and Ball-joints that may have got worn or damaged
- With worn out bushings when the tires experience lateral contact forces from the road, the play caused by worn out bushes allows the suspension to move out of its alignment and cause premature and uneven tire wear.
- Due to the worn out bushings the Lower control arm is now having play at the bushing and ball-joint locations and therefore the lower arm is not anchored to the subframe properly.
- Poor handling of the car is a result of all the factors mentioned above
Suspension Warning message
- The message generally appears in vehicles that have a self-adjusting Air suspension system.
- The warning message would vary from one vehicle to another. The message would generally look like, “Immediate Service/Repair Required” warning message light in the Display.
- While the actual cause can be diagnosed using the manufacturer’s diagnostic tool plugged in through the OBD II port, there are some air suspension components you could inspect on your own as well. They are:
- Air Compressor malfunction
- Air Strut leakage
- Valve Block blockage
- Air-line leakages
In this brief article we have discussed how to diagnose suspension problems that are common in most cars, and troubleshooting tips on maintenance.
Please feel free to ask in case of any questions or comments.