Driver side, front end suspension clunk / pop when slowing down

[danmm7]

2011 S4 with close to 75k miles. Stock suspension.

Over the last few weeks I've noticed that when i am slowing down to a stop light/sign, most of the time, my car will make a slight clunk/popping sound from the front suspension (driver side). It is not too loud and it does not happen every single time, but when it happens, i can clearly hear it, even feel it. Once it pops, then i can drive for awhile without this happening again. In other words, it doesn't happen at every stop.
The clunk can also happen when i am pulling out of my driveway or sometimes when going over road bumps.

There is NO clunk/pop when i am turning, so this is not related to steering.
No other vibrations or weird noises.

So, for those who are intimately familiar with the S4 suspension, given my mileage (75k), what could be causing this suspension noise? Clearly something is getting loose and/or worn out. Where do i start?


Thanks in advance!

[jsh139]

I'd start with looking at the easy things. Swaybar endlinks, CV joints, and control arms.

[danmm7]

I'd start with looking at the easy things. Swaybar endlinks, CV joints, and control arms.

Well, VISUALLY - everything looks great. Nothing broken, nothing leaking, nothing loose.

To start replacing each one of those parts, just for the sake of trying to figure it out would get very expensive very fast. I am sure new CV joints and control arms are not cheap.

[eurotic]

The very first thing I would look at is the lug bolts. I had similar clunking and it turned out that the bolts had backed off slightly, just enough that under braking and/or acceleration I'd get a clunk.

[danmm7]

The very first thing I would look at is the lug bolts. I had similar clunking and it turned out that the bolts had backed off slightly, just enough that under braking and/or acceleration I'd get a clunk.

Good idea... but i just put on new wheels last week. I know the lug bolts are all fine.
The clunk was there before and it is still here. :(

[SwankP3RF3ct10n]

Does it feel/sound/seem like it's almost somewhere down low below your left foot when it happens?

[kcobourn]

Don't forget to check motor mounts.


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[kcobourn]

Don't forget to check motor mounts.


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[danmm7]

Does it feel/sound/seem like it's almost somewhere down low below your left foot when it happens?

Yes, kind of, I do feel the "pop" somewhere under my feet.

[S4'ed]

The upper control arm bushings typically will start to fail after about 50000 miles.....just a fact of life of the Audi 4-link front suspension design. The inner bushings start to develop cracks within about 25000 miles...which then get bigger till you get enough slop to make noises......this suspension design puts higher than normal stress on those....also check for play in the 4 ball-joints, one at the outer end of each of the 4 arms. And of course, check your tie-rod ends and sway-bar end-links.

[eurotic]

Does it do it when you are engine braking? Try rolling in 1st gear, accelerate hard and then let off but don't hit the brake and see if it makes the sound. Also if you do that how does the deceleration compare to when you are using the brakes because maybe that test won't generate enough force.

Also are you 6MT or DSG?

[SwankP3RF3ct10n]

Does it do it when you are engine braking? Try rolling in 1st gear, accelerate hard and then let off but don't hit the brake and see if it makes the sound. Also if you do that how does the deceleration compare to when you are using the brakes because maybe that test won't generate enough force.

Also are you 6MT or DSG?

Engine mount(s) if you hear a clunk as you get off?

[danmm7]

Does it do it when you are engine braking? Try rolling in 1st gear, accelerate hard and then let off but don't hit the brake and see if it makes the sound. Also if you do that how does the deceleration compare to when you are using the brakes because maybe that test won't generate enough force.

Also are you 6MT or DSG?

I am DSG.

[Wreckm]

I get the same slight popping // little rattle also.
On a flat surface backing out the driveway slow.
I thought it was the lower straight control arm because it has damage to it from bottoming out so
i thought the rubber was done.
But now i think about it... I hope its not the motor mount

[eurotic]

Engine mount(s) if you hear a clunk as you get off?

I was just thinking you can maybe rule out brake components. I've had loose calipers (different car) that would clunk and it was due to carrier bolt loosening. However as you suggest it might point to engine mounts too. Especially if you get the car up to speed, go to neutral and do a few hard stops to see if you get the clunk. (not meaning you specifically Swank)

[ntsantos]

Do you have an aftermarket exhaust/piping? I had a clunk that I thought was suspension, turns out the larger 2.5" piping would bump against the subframe brace when I went over small bumps.

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[SwankP3RF3ct10n]

I get the same slight popping // little rattle also.
On a flat surface backing out the driveway slow.
I thought it was the lower straight control arm because it has damage to it from bottoming out so
i thought the rubber was done.
But now i think about it... I hope its not the motor mount

Yep, this is the sound I've had for a bit. I've gone through everything I can think of and I'm starting to wonder if it isn't my left engine mount. They are such a pain in the ass to change out. Ugh! I'd rather have some confirmation from someone else before I go digging. Thing is, nothing has leaked yet and no soft code for engine mounts, so what the heck? Do the 2010's not have engine mounts with the fluid and resistors in them?

[kcobourn]

Yep, this is the sound I've had for a bit. I've gone through everything I can think of and I'm starting to wonder if it isn't my left engine mount. They are such a pain in the ass to change out. Ugh! I'd rather have some confirmation from someone else before I go digging. Thing is, nothing has leaked yet and no soft code for engine mounts, so what the heck? Do the 2010's not have engine mounts with the fluid and resistors in them?

You're describing my symptoms and I ended up with new upper arm bushings and motor mounts. Both were bad.

No more clunk.


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[SwankP3RF3ct10n]

You're describing my symptoms and I ended up with new upper arm bushings and motor mounts. Both were bad.

No more clunk.


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Mine's more like a golf ball is stuck somewhere rattling around. I have a sneaking suspicion that it's the motor mount. The upper control arms bushings have a slight split in them, but so do the rights and this problem is not on that side. Also, the split isn't a bad tear where it's completely apart or anything.

[cjw]

This came up for me today. It's only when braking for the most part. Hard braking/accel seems ok, just the initial application of the brake - light clunk you can feel (not through the streering though).

I'll have to get under the car and check stuff.

[danmm7]

This came up for me today. It's only when braking for the most part. Hard braking/accel seems ok, just the initial application of the brake - light clunk you can feel (not through the streering though).

I'll have to get under the car and check stuff.

OP here..... i think I FIXED the problem.

Pop the hood slightly and drive around like that. On my car, as soon as i had the hood slightly open, the pop/clunk went away. I was truly amazed. People on this forum blamed this type of pop/sound/clunk on the 4 rubber bushings/stops attached to the hood that are touching the body when the hood is fully closed. Many people here had this problem and they fixed it by replacing or modifying these rubber stops.

However, i am not convinced this was 100% my issue and the only source of the pop/clunk. Keep reading...


Interestingly enough....after i closed the hood, without replacing or modifying the rubber bushings on it at all, the pop/clunk was gone for almost a day. Car was perfectly quiet. People suggested i put some felt pads on the rubber bushings/stops, but since i did not have any felt pads around, i drove the car as is. I only out some grease on top of the rubber stops. Well, The pop came back. :( I could feel it too....very slight, under my feet. Under braking....and when taking off. Tiny small clunk/pop. I opened the hood again.... and it went away. And then again, came back after another day of driving.
Opened the hood again....drove around....but this time the clunk/pop was still there, even with hood slightly open!!! :( :(
Clearly, this time it was not coming from the hood rubber bushings. I was very very puzzled.

Lifted the car, removed the under body plastic shields and started inspecting all the large bolts on the frame and suspension. All were very very tight, except ONE. The front facing, driver side bolt holding the factory chassis brace was somewhat loose. (I don't have Alu Kreuz yet) It took a few turns with the ratchet to get it tight. Clearly it was not torqued well for unknown to me reason. All other bolts on the brace were very tight. I put everything back together and lowered the car. I also installed some felt pads on the hood rubber stops.
For the last 2 days i have been driving the car everywhere and it is very quiet. No pops, no clunks, no noises. Not sure if it's all in my mind now or not, but the car also feels "better put together", more solid.

So....my advice - check your hood rubber stops first. Put some felt pads on them or replace them. If noise is still there.... go under the car and check ALL bolts, especially those holding the chassis brace.

[Wreckm]

need to check those chassis bolts when i get off work Hood popped / felt pads didn't work.