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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Suspension | Brakes | Chassis > E92 front suspension thud over bumps or potholes



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      08-24-2020, 08:24 AM   #1
kusy
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E92 front suspension thud over bumps or potholes

Hello, i know there are plenty of topics about suspension rattles, clunks and other noises, but none of them match my "thud". It sounds exactly like worn control arm bushing or something like that on older models. I couldn't replicate any sounds or find any play in control arms, sway bar links or tie rods. Everything seems solid. I can only hear it when driving, sounds kind of like shocks hitting bumpstops, but not really. Everything is tight, steering rack, all braces and all suspension bolts. Is there any way to check the front shock? I currently have bilstein b12 with around 10k miles on it.

Thank you for any suggestions.

VIDEO of control arm bushings, i guess them being hydro-filled that this is normal? both sides the same amount of play.

https://drive.google.com/file/d/1mFO...oc0oPUBeY/view
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      08-25-2020, 10:34 AM   #2
lowrydr310
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I had this thud sound too. Visually my thrust arm bushings looked fine, I twisted and even used a prybar and couldn't find any free play, but I went ahead and replaced them anyway because I had all the symptoms of failed bushings (random vibrations at various speeds, thud when hitting bumps, thud when braking sometimes). It wasn't immediately obvious just from looking at everything mounted, however after removing the thrust arm it was very obvious that the bushings were trashed. Huge cracks. All the symptoms were gone after replacing with new parts.
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      08-25-2020, 12:34 PM   #3
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Could be Top strut mounts either bad or loose bolts (3 nuts per mount). If loose, they can be re-tightened with a spanner/socket.

Did you change your mounts when the Bilsteins were added?
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      08-26-2020, 08:00 AM   #4
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Thanks for responses,

that's the thing, no vibration whatsoever or noise when braking, yes new mounts and all the bolts are tight.
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      08-26-2020, 03:48 PM   #5
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Quote:
Originally Posted by kusy View Post
Thanks for responses,

that's the thing, no vibration whatsoever or noise when braking, yes new mounts and all the bolts are tight.
Just to confirm really but are the alignment pins on the mounts sitting in the holes?

The reason I ask is because I recently had new mounts + shocks fitted at the front and the garage did not align the mount properly and ended up tightening the mounts which lead to the pin making a dent in the strut tower. The car was running very firm and many thuds and bangs etc.

Got the garage to re-install the mounts the correct way and they ride transformed into a luxury cruiser with hardly any bangs or thuds...
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      09-01-2020, 04:37 AM   #6
kusy
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well, it was the shocks themselves..
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      09-02-2020, 12:10 PM   #7
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Quote:
Originally Posted by kusy View Post
well, it was the shocks themselves..
Glad to know you found the problem. Were they leaking or sitting loose in the strut mount?
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      09-05-2020, 05:07 AM   #8
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Quote:
Originally Posted by bmw_solid View Post
Glad to know you found the problem. Were they leaking or sitting loose in the strut mount?
x2 ^

Glad you found your issue, but I'm about to hijack your thread because I recently installed Koni Yellows, Powerflex thrust bushings, tension control arms, new top hats and new lowering springs. The thrust control arm ball-joints are the only things I did not replace as when I took the rear lower control arm out they seemed very much fine. Car is an E91 XI.

Tie rods/steering feels tight as it should be. Everything was tightened correctly at ride height. When going over some bumps I get the THUD noise/feeling as if the shocks are blown. The Koni's are on the softest setting. I do not see any visible leaking from the shocks though. I do feel as though the front is a little too soft but if I stiffen up the shock I'm afraid the THUD will increase exponentially. All parts were new and installed recently.

Anyone have any suggestions as to where to start?
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      09-07-2020, 02:25 AM   #9
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probably leaking

In my opinion, the ball joint would have to have noticable amount of play when you move the wheel while lifted.. Also you could have faulty shock or something from the whole assembly
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      09-12-2020, 06:42 AM   #10
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Quote:
Originally Posted by stelvio View Post
x2 ^

Glad you found your issue, but I'm about to hijack your thread because I recently installed Koni Yellows, Powerflex thrust bushings, tension control arms, new top hats and new lowering springs. The thrust control arm ball-joints are the only things I did not replace as when I took the rear lower control arm out they seemed very much fine. Car is an E91 XI.

Tie rods/steering feels tight as it should be. Everything was tightened correctly at ride height. When going over some bumps I get the THUD noise/feeling as if the shocks are blown. The Koni's are on the softest setting. I do not see any visible leaking from the shocks though. I do feel as though the front is a little too soft but if I stiffen up the shock I'm afraid the THUD will increase exponentially. All parts were new and installed recently.

Anyone have any suggestions as to where to start?
I think your best bet is to do a search in this section of the forum on Koni yellows as there are millions of threads on these shocks. If you can't find any answers, then your best bet is to make a new thread in this section with a good title so people with knowledge of konis will e able to understand your problem from your thread title.
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      09-22-2020, 09:49 AM   #11
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Quote:
Originally Posted by stelvio View Post
x2 ^

Glad you found your issue, but I'm about to hijack your thread because I recently installed Koni Yellows, Powerflex thrust bushings, tension control arms, new top hats and new lowering springs. The thrust control arm ball-joints are the only things I did not replace as when I took the rear lower control arm out they seemed very much fine. Car is an E91 XI.

Tie rods/steering feels tight as it should be. Everything was tightened correctly at ride height. When going over some bumps I get the THUD noise/feeling as if the shocks are blown. The Koni's are on the softest setting. I do not see any visible leaking from the shocks though. I do feel as though the front is a little too soft but if I stiffen up the shock I'm afraid the THUD will increase exponentially. All parts were new and installed recently.

Anyone have any suggestions as to where to start?
I have this exact same issue. Basically even small cracks and Indentations in the pavement feel like Iíve run over craters. I took the car back to get upgraded z4 and m3 mounts, letís see what happens.
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      09-23-2020, 03:07 AM   #12
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Quote:
Originally Posted by thormessiah View Post
I have this exact same issue. Basically even small cracks and Indentations in the pavement feel like Iíve run over craters. I took the car back to get upgraded z4 and m3 mounts, letís see what happens.
Have you also replaced the control arm bushings?
Are you referring to using the Z4/M3 bump stops?
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      09-23-2020, 09:01 AM   #13
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Quote:
Originally Posted by stelvio View Post
Quote:
Originally Posted by thormessiah View Post
I have this exact same issue. Basically even small cracks and Indentations in the pavement feel like I’ve run over craters. I took the car back to get upgraded z4 and m3 mounts, let’s see what happens.
Have you also replaced the control arm bushings?
Are you referring to using the Z4/M3 bump stops?
I have less than 6 month old m3 front control arms all the way around. I got the TRW set. And yes that's what I meant
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      09-24-2020, 02:35 PM   #14
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Quote:
Originally Posted by thormessiah View Post
I have less than 6 month old m3 front control arms all the way around. I got the TRW set. And yes that's what I meant
Did you tighten the control arms when the car was on the ground/ramps? If you tighten any OEM bushing when the weight of the car is in the air, they will wear out ridiculously fast.
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      09-24-2020, 03:15 PM   #15
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Quote:
Originally Posted by stelvio View Post
Did you tighten the control arms when the car was on the ground/ramps? If you tighten any OEM bushing when the weight of the car is in the air, they will wear out ridiculously fast.
Iím not sure I had my shop do it for me. I felt it as soon as I got in for the first drive tho, so I donít think itís that
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