In this brief article we are going to discuss the different Mercedes W212 Suspension problems, what the causes are, and Troubleshooting Tips.
What are the most common suspension issues in a Mercedes W212?
The most common Mercedes W212 suspension issues are:
- Front Knocking or Creaking
- Steering Vibration at High Speed
- Creaking and groaning noise
- Squeaky and Bouncy Suspension
- Clunking Noise in normal driving
- Clicking Noise when turning
- Self-Steer under acceleration
Mercedes W212 Suspension Set-up
The W212 is the chassis-type for the fourth generation of Mercedes-Benz E-Class made from 2010 to 2016. The models under the W212 platform were E200, E250, E300, E350, E400, E500 and E63.
In the W212 Platform, the Front suspension set-up was changed from a Double Wishbone set-up in the W211 to a MacPherson Strut. There are 2 separate Lower Control Arms and therefore 2 Lower Ball-joints for wheel Spindle with a Torsion bar & coil springs.
In the V8 models and AMG models there was AirMatic or 4-corner Air suspension with adaptive Dampers instead of coil springs. The 4Matic models (with All-wheel Drive) had a one-piece Lower Control Arm instead of the 2 separate Lower Arms found in the regular models.
The Rear suspension of the W212 is a 5-link independent suspension with Torsion bar & coil springs similar to the previous W211.
Front Knocking or Creaking noise going over Bumps
- Knocking or Creaking noises while going over bumps coming from the front suspension
- Additionally there is Popping and Clunking noise coming from the front suspension when Steering the wheels in parking or slow speed
Troubleshooting Knocking or Creaking front
Knocking or Creaking in the front suspension could be either due to :
- Worn Out Thrust-Arm Bushings
- Worn Out Thrust-Arm Ball-Joint
- Worn out Top Strut Mount Bushing and Bearing
Worn out Thrust-Arm Bushings
- The Lower control arm, also called “Forward Tension Strut”, is prone to Bushing failure
- The Lower Forward Control arm, 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 control arm bushings are ‘hydraulic + rubber’ type of isolators, because of their dual role of taking load as well as reducing noise and vibration.
- If you find a viscous brown fluid oozing out of the control arm, then it is confirmed that the Lower Control arm bushings have failed due to Rubber rupturing and leaking Hydraulic fluid.
- This failure results in a popping or clunking noise when the wheels are turned.
Worn out Thrust-Arm Ball Joint
- 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 Lifted by the body
- Lock the steering wheel
- Hold the front tire with both your hands in a 6 o’clock position and try to swing the wheel 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
- For a vehicle that has crossed 70K miles, the best course of action would be to replace the whole Lower control arm since it comes with a new bushing and a new ball-joint all pre-assembled
Pro-Tips for Thrust Arms
- The Hydraulic Fluid Bushing generally fails beyond 40K-50K Miles, but it may be worthwhile to replace as soon as you notice suspension noise.
- While replacing the Thrust arm, it would be wise to look for a good aftermarket solution that would give more service life than the 50K 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 Bushing 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.
- In some cases, under Hard acceleration, it feels as if the vehicle is steering itself. This is also a symptom of the Strut Top Mount Failure.
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.
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 Bushings or Ball-joints within the Anti-roll Bar assembly of the suspension
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 an Anti-seize, as prescribed by Mercedes, to the ARB bushing contact surface periodically.
Anti-roll bar (ARB) 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.
- 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 Joint Failure
- 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.
Self-Steer Under Acceleration
- Under Hard acceleration, it feels as if the vehicle’s rear end is steering itself
- Uneven or excessive rear Tire-wear
Troubleshooting Self-Steer Under Acceleration
- The rear of the vehicle’s tendency to spin out is an indication of a Toe-change at the time of acceleration
- This means that the Toe-link of the rear suspension is unable to control the Toe under acceleration
- This means the Toe-link bushings might have worn out and therefore need replacement
- Another reason could be that you have lowered the rear suspension and not used an adjustable Rear Camber Arm to adjust for the Camber gained due to lowered height.
In this brief article we have discussed the different Mercedes W212 Suspension problems, what the causes are, and Troubleshooting Tips.