Help Me Diagnose a Suspension Creak

[NicKnack]

Background Info:

Car is a 2023 MT, with ~15k KM's on it, only suspension related mods are Eibach US Spec lowering Springs.

I installed the lowering springs myself last year and did about ~7k on them trouble free. This issue only started happening about a month ago. I got caught in a pretty heavy rain storm on my way somewhere. The car handled it just fine and it has not thrown any codes or anything, but ever since then I've noticed a suspension creak under very specific conditions. The first time it occurred was actually pulling into a parking lot after driving through that rain.

The Symptoms:

It only occurs when entering or exiting driveways, or steep speed bumps at an aggressive angle, just driving on the road normally or entering relatively flat driveways it's silent. It's only the really aggressive ones where you have to enter at an angle to avoid scraping.

When it happens, it's a creaking noise akin to what it might sound like walking on an old wooden floor, it's not excessively loud, but it's loud enough to be heard from inside if the radio volume is turned down.

I'm guessing it may potentially be the sway bar bushings, since the entry angles on those types of driveways would probably put a lot of torsional force on the bars and the sound I'm hearing is potentially lack of grease at the bushings? The fact that it happens front and rear is also part of why I'm suspecting sway bar bushings, since if it were a control arm bushing or something, I feel like it would be localized to one corner, or side of the car.

Figured I'd ask here as well to see if anyone else has experienced this or if someone a bit more familiar with BMW Suspension design/setups might have something else this could point to?

Any help/ideas are appreciated!

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[lucky phil]

Background Info:

Car is a 2023 MT, with ~15k KM's on it, only suspension related mods are Eibach US Spec lowering Springs.

I installed the lowering springs myself last year and did about ~7k on them trouble free. This issue only started happening about a month ago. I got caught in a pretty heavy rain storm on my way somewhere. The car handled it just fine and it has not thrown any codes or anything, but ever since then I've noticed a suspension creak under very specific conditions. The first time it occurred was actually pulling into a parking lot after driving through that rain.

The Symptoms:

It only occurs when entering or exiting driveways, or steep speed bumps at an aggressive angle, just driving on the road normally or entering relatively flat driveways it's silent. It's only the really aggressive ones where you have to enter at an angle to avoid scraping.

When it happens, it's a creaking noise akin to what it might sound like walking on an old wooden floor, it's not excessively loud, but it's loud enough to be heard from inside if the radio volume is turned down.

I'm guessing it may potentially be the sway bar bushings, since the entry angles on those types of driveways would probably put a lot of torsional force on the bars and the sound I'm hearing is potentially lack of grease at the bushings? The fact that it happens front and rear is also part of why I'm suspecting sway bar bushings, since if it were a control arm bushing or something, I feel like it would be localized to one corner, or side of the car.

Figured I'd ask here as well to see if anyone else has experienced this or if someone a bit more familiar with BMW Suspension design/setups might have something else this could point to?

Any help/ideas are appreciated!

Lubricate the door seals with some Armorall or such like. I haven't heard or it specifically affecting Supras but I've had it with other cars in your situation esp after washing the car or rain. A little chassis flex and the door rubbers creak. Nothing to lose giving it a go.
Phil

 

[NicKnack]

Lubricate the door seals with some Armorall or such like. I haven't heard or it specifically affecting Supras but I've had it with other cars in your situation esp after washing the car or rain. A little chassis flex and the door rubbers creak. Nothing to lose giving it a go.
Phil

I'm not sure if that's it since the creaks are very distinctly coming from in front of/behind me, towards the corners of the vehicle.

But, I do have some Honda Shin-Etsu left from lubricating my MR2's T-Top seals earlier this year so, won't hurt to put some on the door seals.

 

[lucky phil]

I'm not sure if that's it since the creaks are very distinctly coming from in front of/behind me, towards the corners of the vehicle.

But, I do have some Honda Shin-Etsu left from lubricating my MR2's T-Top seals earlier this year so, won't hurt to put some on the door seals.

Let us know how it gos.
Phil

 

[NicKnack]

Let us know how it gos.
Phil

No luck, brought the car inside overnight and did this. Still happens/sounds the same and only under the same conditions. So essentially only when taking driveways/angles that otherwise put flex on the chassis/torsional force on the sways

 

[lucky phil]

No luck, brought the car inside overnight and did this. Still happens/sounds the same and only under the same conditions. So essentially only when taking driveways/angles that otherwise put flex on the chassis/torsional force on the sways

Ok cool. Thanks for the reply.
Phil

 

[licklobster]

strut bearing is my guess. if they're slightly out of whack they will bind then creak when wheels are turned at large angles at low speeds as you describe. you probably compromised one of them on accident when the springs went on, it's very easy to do.

 

[NicKnack]

That could be it for the front, but would that be the rear as well? I'll have to see if I can mount a camera/mic or something under there to try and help me localize it.

I was thinking maybe the Wishbone or Rear knuckle bushings.

I could replace the front strut bearings just in case. I would also just find it a bit weird that they both would start doing this out of nowhere after a year and a bit on lowering springs, and just after driving in heavy rain too.

 

[licklobster]

The rears don't have a bearing because they don't rotate on the strut under tension.

 

[SilverBully]

Did you ever find the culprit? I am having a similar faint squeak/creak when I go over small bumps and suspension compresses - it’s not loud and I can only hear if I’m going slow with the windows rolled down…

I am also on lowering springs and I believe the noise is coming from right rear, I intend on checking the knuckle bushing this weekend so I can start to narrow it down

 

[NicKnack]

Did you ever find the culprit? I am having a similar faint squeak/creak when I go over small bumps and suspension compresses - it’s not loud and I can only hear if I’m going slow with the windows rolled down…

I am also on lowering springs and I believe the noise is coming from right rear, I intend on checking the knuckle bushing this weekend so I can start to narrow it down

I have not, it doesn't effect driveability and only happens under such specific circumstances that I'm just living with it for now. I'm putting the car away for winter next weekend, and at my annual service in the spring I'm going to ask if they can hit the sway bar bushings and rear knuckle bushings

If that doesn't fix it and it happens to be the strut mounts, I'm planning on switching to KW DDC's in a year or two anyways so I can live with it until then

 

[SilverBully]

I have not, it doesn't effect driveability and only happens under such specific circumstances that I'm just living with it for now. I'm putting the car away for winter next weekend, and at my annual service in the spring I'm going to ask if they can hit the sway bar bushings and rear knuckle bushings

If that doesn't fix it and it happens to be the strut mounts, I'm planning on switching to KW DDC's in a year or two anyways so I can live with it until then

I fixed it today by replacing and properly torquing down the wheel hub/lower control arm bolt - the squeak is now gone!

I didn’t know that you’re supposed to torque it down while the suspension under load for some reason this prevents the bushing in there from going bad or so I heard on some YouTube video some time ago.

Anyways, now I have to do the same on the driver side because it squeaks there too just not as loud/noticeable yet.

 

[tracer bullet]

torque it down while the suspension under load

Rubber bushings - they need to be at their normal operating height, which is basically the center of their normal travel, when tightened. So that when the suspensions moving a little bit up and down, the rubber flexes and works as intended. With them tightened in the air, the suspension is at full droop, and then when the car's back on the ground they are already flexed quite hard in one direction, and even more so when you hit a bump.

You'll want to do the other side soon, or you can ruin the bushing if you haven't already.

I suppose the diagnosing part of the thread assumed you had done that correctly. Now you know.

 

[SilverBully]

Rubber bushings - they need to be at their normal operating height, which is basically the center of their normal travel, when tightened. So that when the suspensions moving a little bit up and down, the rubber flexes and works as intended. With them tightened in the air, the suspension is at full droop, and then when the car's back on the ground they are already flexed quite hard in one direction, and even more so when you hit a bump.

You'll want to do the other side soon, or you can ruin the bushing if you haven't already.

I suppose the diagnosing part of the thread assumed you had done that correctly. Now you know.

This right here is how we learn! By breaking shit lol - won’t happen again for sure…


How do I know if they are ruined? Are they oil filled and leak or is there another way to check?

 

[NicKnack]

I fixed it today by replacing and properly torquing down the wheel hub/lower control arm bolt - the squeak is now gone!

I didn’t know that you’re supposed to torque it down while the suspension under load for some reason this prevents the bushing in there from going bad or so I heard on some YouTube video some time ago.

Anyways, now I have to do the same on the driver side because it squeaks there too just not as loud/noticeable yet.

I'll take a look at this but I have the creak at all 4 corners and I didn't undo the LCA's or anything in the front to do the springs.

But I can take a look at those rear bushings next time I have the car up on the lift, or I'll have the dealer take a look. For me personally I just thought it was strange cause it's such a specific scenario that it happens, and it only started happening after driving through what could basically be described as standing water; is how hard it was raining so I figured maybe some grease got washed out of mine

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