C Class Suspension Issues Explained(+Top Most Common Problems)

In this brief article we are going to discuss the different Mercedes C Class Suspension problems, what the causes are, and Troubleshooting Tips.

What are the most common suspension issues in a Mercedes C Class? 

The most common Mercedes C Class suspension issues are:

  • Popping and clunking noise when the wheels turn
  • Creaking and groaning noise
  • Squeaky and Bouncy Suspension
  • Clunking Noise in normal driving
  • Knocking Noise
  • Clicking Noise when turning

Mercedes C Class Suspension Set-up

The suspension system of Mercedes-Benz C-Class W205 platform (current generation of C-Class) is different from the previous generation W204 (2007-2014) platform. In the W204 platform, the Front suspension was a 3-Link MacPherson Strut set-up. 

In the W205 Platform, the Front suspension set-up was changed to Double Wishbone set-up. The upper Control Arm is one-piece, whereas there are 2 separate Lower Arms and therefore 2 Lower Ball-joints for wheel Spindle with a Torsion bar & coil springs.

The Rear suspension is common between the W204 and W205 platforms. It is a Multi-link independent suspension with Torsion bar & coil springs. 

How to Deal With Suspension Problems in an E Class Mercedes?(+7 Troubleshooting Tips)

Popping and clunking noise when the wheels turn

  • When Steering the wheels in static or slow speed, there is Popping and Clunking noise coming from the front suspension
  • Additionally may give noise during normal driving

Troubleshooting Popping and Clunking

Worn out Thrust-Arm Bushings

  • The Lower Forward Control arm, also called ‘thrust arm’ in the front suspension handles the longitudinal forces coming onto the wheels when driving. 
  • The Thrust arm is designed such that the longitudinal wheel forces directly load the thrust arm bushings (white arrow). These bushings happen to be ‘hydraulic + rubber’ type of isolators because of the dual role of taking load as well as reducing noise and vibration.
  • Even though the W204 design improved upon the W203 bushing design (which was failure prone), the W204 bushings are also susceptible to Rubber cracking and splitting problems.
  • This failure results in a popping or clunking noise when the wheels are turned. 
  • The thrust arm bushings typically last approximately 30,000 miles, but it may be worthwhile to replace as soon as you notice suspension noise.

Pro-Tip for Thrust Arms

  • While replacing the Thrust arm, it would be wise to look for a good aftermarket solution that would give more service life than the 30K miles or so offered by Rubber-Hydraulic bushes.
  • You could either go for a ‘Solid’ Rubber bushing or a Mono-Ball type of Bearing instead of the Rubber-Hydraulic Bush

Worn out Top Strut Mount and Bearing

  • The suspension strut is attached to the body through the top Strut mount. 
  • These top strut mounts have integral bearings that facilitate the smooth rotation of the strut while steering the wheels. 
  • These top strut mount bearings are designed to support the load of the front suspension and will become noisy when bearings fail and no longer allow free rotation. 

Creaking and groaning noise

  • The front or rear suspension gives a creak or groan Noise while going over bumps.

Troubleshooting Creaking and groaning noise

Broken Coil Spring

  • The Creak and Groan noises often come from two Broken pieces of spring binding and making contact as the spring compresses. 

Suspension Height Modifications/Lowering

  • If any lowering springs were installed on the car, the springs may not always be seated in their perches properly. As a result of this, the spring can make noise. 
  • This possibility is higher in the case of the front suspension, as the spring can get hung up or binded instead of rotating freely when trying to turn. The result is a creaking and groaning noise.

Squeaky and Bouncy Suspension

  • The car feels bouncier than usual and also squeaks for minor road undulations

Troubleshooting Squeaky and Bouncy Suspension

Shock Absorber Failure

  • If you feel that the suspension has increased bounciness, it could be a case of shock absorber failure. The failed shock absorber can no longer dampen the suspension’s ‘Bounce’ motion.
  • A suspension Strut that has a binding or frozen piston rod on the shock absorber tends to squeak for even minor movement
  • The easiest thing to first do is to inspect the shock absorber body, and look for signs of oil that would indicate a seal failure.
  • A failed shock absorber need not necessarily leak when it fails. If has reached its end-of-life and worn out internally, it could also lose all its damping action and eventually seize

Clunking Noise in normal driving

  • ‘Clunking’ noise during normal driving especially on bad and rough road patches that cause the vehicle to “Roll” more.
  • The same ‘Clunk’ noise reduces on smoother roads

Troubleshooting Clunking Noise in normal driving

  • For most car suspensions, a ‘Clunk’ Noise is more related to the Anti-roll Bar assembly of the suspension
  • The same would be the case with the Mercedes C Class

Failed Anti-roll Bar Bushings

  • 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.
  • The bushings can be lubricated with vaseline or a specialized Anti-seize that is suited to the ARB bushing material periodically.

Anti-roll bar End link Failure

  • The ARB-to-suspension connection is done using ARB end links. 
  • On the front axle, the end links use a sealed ball joint design that has a significant range of motion sufficient for the various movements of the front suspension. 
  • The rubber boot that protects the end link Ball-joints can tear, allowing the joint lubrication to seep out and exposing the ball joint to corrosion. The result is a clunking noise from the worn joint. 
  • If the end links’ mounting fasteners have loosened on either end, it could result in clunking noise.
  • On the rear suspension ARB end links, rubber bushings are used instead of ball joints. These end link bushings can age and then start to squeak. 
  • Use of Lubricants could temporarily solve the squeaking sound problem. But it is always recommended that new end links be fitted.

Knocking Noise

Every time the car goes over bumps, you hear a clunking or knocking noise.

Troubleshooting Knocking Noise

Failed ball joints

  • The front suspension components utilize ball joints at the control arms and tie rod ends. The big advantage with ball-joints is that they allow an extensive range of motion. 
  • By design, ball joints are quite robust and meant to last; however, tearing of the rubber outer boot can lead to entry of dust and moisture into the joint leading to premature failure
  • This ball joint Failure would often be followed by a clunking or knocking noise. 
  • There is an easy way to check ball-joints without removing any of the suspension parts. Firmly grasp on a front wheel, with both of your hands at six o’clock position.  Now try to swing the tire up and down. If you sense that there is excessive ball joint play then these ball-joints have failed.

Clicking Noise when turning

The noise happens when the car is parked and you are trying to rotate the steering wheel.

Troubleshooting Clicking Noise

CV joints issue

  • In some models with 4MATIC all wheel drive system, you may experience a clicking noise coming from the front suspension when turning
  • This sound is most likely due to a worn front CV joint. CV joints can wear, especially with a torn outer rubber boot exposed to dirt and moisture. Apart from seepage of lubrication, the failed CV joint will also begin to develop a click sound. 
  • These clicks will become more obvious if you rotate the steering wheel while the vehicle is parked.

Conclusion

In this brief article we have discussed the different Mercedes C Class Suspension problems, what the causes are, and Troubleshooting Tips.

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