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S CLASS W221 S350 AWD, M CLASS W164 ML350 SUV, ROLLS-ROYCE SILVER SERAPH, ASTON MARTIN V12 VANQUISH
W221 FRONT SUSPENSION SQUEAK.
I have on my 2010 W221 S Class 58k miles, a very annoying squeak from the Left Front Suspension. This can only be heard at very low speed but over the slightest bump or undulation. If the car was not so quiet it would not be heard at all. It is not from a ball joint or suspension arm pivot. When I get the car to make the noise by stepping on the left front door tread plate, I, and everyone else hearing it reckon it comes from the left front suspension turret. It does sound just like a worn Shock Absorber or like a squeak from a rear leaf spring in days gone by. But of course this car has neither. It has an air suspension strut. I cannot see how it can be anything else, but someone on here once said that these suspension struts don't make any noise and either work or fail. Anyone else experience a noisy air strut? Is there any cure apart from replacement?
To diagnose this you first start by disconnecting the sway bar links to see if the noise persists. If the noise goes away, you know it's the sway bar. If it doesn't, it's one of the booted joints at the bottom of the suspension and there are three of them. The likelihood is that one of them needs some grease.
An easy way to tell if one of the lower arms is an issue, is to place your hand on them and either pull down on the corner of the car or have someone push down on that corner. You should feel a vibration, along with the squeak, that will indicate a worn ball joint or bushing.
It is not from a ball joint or suspension arm pivot.
How sure are you about this?
Originally Posted by MercedesLondon
I have on my 2010 W221 S Class 58k miles, a very annoying squeak from the Left Front Suspension. This can only be heard at very low speed but over the slightest bump or undulation. If the car was not so quiet it would not be heard at all.
... like a squeak from a rear leaf spring in days gone by.
I had this exact noise on my S600 with ABC (not air), and it was the front lower control arms. Replacing them stopped the noise. Hope this helps!
There are only so many choices. In order of likelihood.
1) Sway bar endlinks
2) Outer tie rod ball joint
3) One of the control arm bushings or ball joint. There are three. Upper control arm (upper wishbone), lower front control arm, and lower rear stabilizer.
4) Inner tie rod ball joint.
S CLASS W221 S350 AWD, M CLASS W164 ML350 SUV, ROLLS-ROYCE SILVER SERAPH, ASTON MARTIN V12 VANQUISH
Thanks, but I'm way past that. Said I'd checked all and not from a ball joint or suspension pivot point.
To itemize :...
Front sway /anti-roll bar disconnected, road tested, noise still there. Sway bar also checked for noise by moving by hand whilst disconnected.
Left hand tie link also checked; rubber boots taken off, ball swivels inspected for pits or rust, (what you can see of them), fully greased, rubber boots replaced and refitted to sway bar.
Left hand front forward lower control arm replaced with genuine MB part.
Left hand steering track rod end replaced with genuine MB part.
Left hand front rear lower control arm removed, fully inspected, ball joint rubber boot removed ball swivel inspected for pits or rust, (what you can see of it), fully greased, rubber boot replaced and arm refitted.
Upper wishbone checked for play and noise, outer ball joint rubber boot removed ball swivel inspected for pits or rust, (what you can see of it), fully greased, rubber boot replaced and arm refitted.
I can only think it the strut, unless someone can suggest something else. Maybe lubrication of the strut, (inside or out)? Anyone done anything to the strut? I haven't taken the large bellows on the strut down, to look inside there yet. Maybe something to be lubricated in there.
Apologies, wrong info given on the age of the car. It is a late 2012 face-lift model, (I was thinking of my M Class when I said 2010).
S CLASS W221 S350 AWD, M CLASS W164 ML350 SUV, ROLLS-ROYCE SILVER SERAPH, ASTON MARTIN V12 VANQUISH
Squeak is only at very low speed and activated by the slightest undulation or upward movement.
Like going down my drive over the different areas of concrete, (minimal height difference between each one. Or the entrances to my drive are about 1" above road level. If I go in at an angle left wheel first, get a loud squeak with nothing when the right wheel goes over. If I go in right wheel first there is a slight squeak from the left, followed by a louder speak from the left when the left wheel goes over.
All at VERY low speed. Hear nothing on the road, even at 15 mph +/-.
90% of the time it is the control arm bushing. the littlest amount of movement like opening the door or just as your sitting in car. Most of it has to due with age. And if they are wet it will not squeak. The other part I found is a sway bar frame bushing. If it was a ball joint you would have play in the tire and it would make noise when turning or steering wheel not returning to center. Like the other member said hold your hand on the bushing and have someone lightly push down on car you will find the one making the noise. The 550 are heavy cars they will take their toll on front end parts. OH , and stay away from Auto Zone or other part stores like that. BUY oem part for items like this. And if you think it cost to much you should have bought a TOYOTA.
This happened with my W220. First the front end squeaked, when crossing small bumps. Changed a front strut and some other front end parts with my indy. It still squeaked!! One day the squeak went away. Months later something was apparently loose and once in a while I'd feel bumps when there were no bumps in the road. Thought I was imagining it. It would come and go... One day, I had to make a U-turn where you turn the wheels all the way left, and BOOM, the bumps were back with a vengeance, It was apparent that there was something at the left wheel, where all the work had been done, that was loose and turning the wheels all the way left would activate this anomaly. I tried everything to get the car back to normal, backing up, turning right, etc. Anyhow, I traded it and bought my W221 which I love! Best advice find a shop where they know front end mechanicals and will know what to look for. Shops like that which are honest are hard to find, though. We had one in my town where the guy was totally honest; he retired and closed up. Another shop here locally rips people off every day. Sells repairs when NO repair is needed! So.... good luck to you.
Last edited by tonylinc; Jan 12, 2020 at 03:50 PM.
Reason: Because editing is Fun
S CLASS W221 S350 AWD, M CLASS W164 ML350 SUV, ROLLS-ROYCE SILVER SERAPH, ASTON MARTIN V12 VANQUISH
If you see my posting on December 18 I've been through all of these things time and time again. I should have stuck with my initial gut feeling and did before what I did today; Took the strut off and tested it. With the base on the floor and pushing down on the top, got the squeak sound exactly as I heard it in the car. Stripped down the strut, to find the noise was in fact coming from the shock absorber and that was in fact leaking fluid at the top end. Now need to find a new shock absorber alone. From what I've found so far, the bellows at the top can be obtained but the shock absorber seems not sold as an individual part. I'll look again in the morning.
S CLASS W221 S350 AWD, M CLASS W164 ML350 SUV, ROLLS-ROYCE SILVER SERAPH, ASTON MARTIN V12 VANQUISH
Does anyone, anywhere know where these shock absorbers can be obtained on their own without the Air Spring fitted to it? Somebody must supply them or have the ability to repair them to manufacturers specifications. Seems daft having to pay out anything between $750 and $1300 for something when you don't need the most expensive part of it. Bilstein ones for the left front are currently unavailable in any event.
... most of the Airmatic complaints I see, especially on the GL forum, relate to leaking air bellows and related components like the air compressor.
When folks complain about Mercedes, I query what life do they expect from a hydraulic shock absorber. On those SUVs, the rear shocks are standalone and mostly fail at 75-80 k miles. Referring then to the fronts, I then query why the air bellows would be designed to last any longer than the integral shock absorber. I suspect most with failed bellows also have failed hydraulics since it’s usually similar or just a little more mileage. Perhaps if they’d noted the hydraulics failure they might have replaced the strut before the air leak hurt the compressor.
I have a 2011 CL 500 66k miles, well serviced and maintained. It has developed a squeak that I believe comes from the air suspension. I have sprayed all the ball joints and sway bar bushes with silicone spray but this has not eradicated the squeak. If I drive along with the air suspension on the high setting (used for steep driveway inclines) the squeak does not happen. From your posts you have been very thorough in eliminating other possible causes so I derive a lot of confidence that you did get to the real problem. I would like to know how you finally resolved the problem and the rough cost please. Thanks. Ray
S CLASS W221 S350 AWD, M CLASS W164 ML350 SUV, ROLLS-ROYCE SILVER SERAPH, ASTON MARTIN V12 VANQUISH
Originally Posted by RayDavisinDevon
I have a 2011 CL 500 66k miles, well serviced and maintained. It has developed a squeak that I believe comes from the air suspension. I have sprayed all the ball joints and sway bar bushes with silicone spray but this has not eradicated the squeak. If I drive along with the air suspension on the high setting (used for steep driveway inclines) the squeak does not happen. From your posts you have been very thorough in eliminating other possible causes so I derive a lot of confidence that you did get to the real problem. I would like to know how you finally resolved the problem and the rough cost please. Thanks. Ray
It was the front Right Lower Forward Control arm.
Although the holding nuts and bolts were very tight it was either the taper on the ball joint rotating and/or the metal center tube to the front bush rotating. More likely the latter.
In any event fitted a new arm and all has been quiet since. Can't remember what the part cost was.
It was the front Right Lower Forward Control arm.
Although the holding nuts and bolts were very tight it was either the taper on the ball joint rotating and/or the metal center tube to the front bush rotating. More likely the latter.
In any event fitted a new arm and all has been quiet since. Can't remember what the part cost was.
Ahh, not the air suspension then. Interesting! Thanks for your prompt reply.
So you confirmed the noise in the air strut OFF of the vehicle but it turned out to be the lower forward arm instead? Im having the same issue except its also accompanied by a clunk you can hear and feel in the tire. I dont see or feel any joint play and the squeak is loudest at the top of the shock tower. I can feel it in the body of the strut too. So i just want to confirm that in your case it WAS NOT the strut. Correct?
So you confirmed the noise in the air strut OFF of the vehicle but it turned out to be the lower forward arm instead? Im having the same issue except its also accompanied by a clunk you can hear and feel in the tire. I dont see or feel any joint play and the squeak is loudest at the top of the shock tower. I can feel it in the body of the strut too. So i just want to confirm that in your case it WAS NOT the strut. Correct?
The strut was not removed. but the lower control arm cured the problem. If you are detecting noise that appears to come from the top of the shock could the top mount be worn or shot? I haven't had top mount problems on this car but did have on a similar large BMW. I'm now grappling with a slight squeak from the rear that I have concluded is due to the worn strut dust covers that have allowed dust or water to get in. The dust covers do not look expensive but fitting them is a big job - I think. I am soon to attempt 'wrapping' them whilst in situ. Good luck with your diagnosis and repair.
I also had squeeks and also a thud when going over small cracks in the roads. Mechanic diagnosed it to lower control arms rearwards. Since the car had almost 150K KM on it, I replaced all of the control arms and sway bar links in the frontend. The car drives so tight and nimble now. Fun!
2010 CL550 4matic with the same problem, the worst part is i just replaced A TON of parts this week!(forward and rearward lower control arms, outer tie rod links, sway bar links, air suspension springs/struts..these are all brand new parts, this car is well maintained) it makes the noise whether stationary or driving, in the video im just lifting and lowering the suspension. it was fine for a few days i believe, and then this started. also, this video isnt great..it creaks/squeaks much more when driving/turning the wheel.
Last edited by COUPCONNOISSEUR; Dec 19, 2025 at 08:13 PM.
2010 CL550 4matic with the same problem, the worst part is i just replaced A TON of parts this week!(forward and rearward lower control arms, outer tie rod links, sway bar links, air suspension springs/struts..these are all brand new parts, this car is well maintained) it makes the noise whether stationary or driving, in the video im just lifting and lowering the suspension. it was fine for a few days i believe, and then this started. also, this video isnt great..it creaks/squeaks much more when driving/turning the wheel.
In this video it makes big “ snaps”.. Are you sure you torqued the lower control arms bolts on the car frame side correctly AND at correct car level?
Sounds like something snaps with car level changes, which could be the arms mounting core that turns when rubber around the core gets enough torque with car level change.
Arms mounting bolts have high torque to lock the joint core in place and torquing of the bolts needs to be done when gar is in the correct level so the arms can move up-down in both directions without putting too much torque on the rubber around the cores. For the level I use the zero level that is set to the Airmatic.
In this video it makes big “ snaps”.. Are you sure you torqued the lower control arms bolts on the car frame side correctly AND at correct car level?
Sounds like something snaps with car level changes, which could be the arms mounting core that turns when rubber around the core gets enough torque with car level change.
Arms mounting bolts have high torque to lock the joint core in place and torquing of the bolts needs to be done when gar is in the correct level so the arms can move up-down in both directions without putting too much torque on the rubber around the cores. For the level I use the zero level that is set to the Airmatic.
Hey arrie. Yes, before changing all lower control arms I measured the distance from the center of the hub to the bottom of the wheel well(it was 15-15.5”) after installing all the new lower control arms I used a second jack to bring the hub to that exact height again before torquing them. Also, after replacing all these parts I brought it to a shop, just to have an alignment done. I’m worried maybe they did something wrong.
also, I’d like to be as thorough as possible. I replaced the outer tie rods, not the inners. I doubt that’s the issue but I’m trying everything, could that be it?
Last edited by COUPCONNOISSEUR; Dec 21, 2025 at 01:46 AM.
Hey arrie. Yes, before changing all lower control arms I measured the distance from the center of the hub to the bottom of the wheel well(it was 15-15.5”) after installing all the new lower control arms I used a second jack to bring the hub to that exact height again before torquing them. Also, after replacing all these parts I brought it to a shop, just to have an alignment done. I’m worried maybe they did something wrong.
also, I’d like to be as thorough as possible. I replaced the outer tie rods, not the inners. I doubt that’s the issue but I’m trying everything, could that be it?
What torque did you use on the arm bolts?
I’m a bit at lost with inner and outer tie rods. What do you call those?
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