[sle39lvr]

Symptoms
When driven slow, over small undulations, I get a suspension knock from each/both sides from the front. This does not occur on lateral movements, only vertical ones at slow speeds.

My initial suspicion was - front sway bar links. Just replaced them and no difference.

Also double checked the strut tower nut at the top.

So I am guessing this could be worn front sway bar bushings?

Car
E90 @ 130K Miles.
Coil-over suspension lowered just below sport height @60K miles
M3 control arms @ 80K miles
New heavy duty steering rods @90K miles

[sabino56]

I had similar condition. Knock on left side only over small bumps. Of course hard to say if same, but in my case it turned out to be the strut. Strut was shot, no damping and sound went away after replacing.

I’d think sway bar bushings, if bad enough to cause a knock would be visibly bad?

[sle39lvr]

Originally Posted by sabino56

I had similar condition. Knock on left side only over small bumps. Of course hard to say if same, but in my case it turned out to be the strut. Strut was shot, no damping and sound went away after replacing.

I’d think sway bar bushings, if bad enough to cause a knock would be visibly bad?

I get it on both sides now. Visibly, there is nothing there to notice on the sway bar bushings...

I ordered them anyway since they are the only parts I still have stock and not replaced (ever). Also they were pretty inexpensive compared to a new strut.

[feuer]

Check the strut mounts and strut bars.

[mweisdorfer]

Originally Posted by sle39lvr

Symptoms
When driven slow, over small undulations, I get a suspension knock from each/both sides from the front. This does not occur on lateral movements, only vertical ones at slow speeds.

My initial suspicion was - front sway bar links. Just replaced them and no difference.

Also double checked the strut tower nut at the top.

So I am guessing this could be worn front sway bar bushings?

Car
E90 @ 130K Miles.
Coil-over suspension lowered just below sport height @60K miles
M3 control arms @ 80K miles
New heavy duty steering rods @90K miles

If you don't have adjustable sway bar links on a lowered car, the links will go bad considerably faster. My humble suggestion would be to invest into a set of whiteline adjustable links for the front. Look up the part number on their website & then order it from FCP Euro. You'll get a lifetime warranty on them.

Or

You could get a front & rear set from Hotchkiss. I had them, but didn't have as much luck with them.

I really like my whiteline links in the front. Unfortunately, they don't make a link for the rear. I just ended up putting Meyle HD beefed up links in the rear.

[sle39lvr]

Originally Posted by mweisdorfer

If you don't have adjustable sway bar links on a lowered car, the links will go bad considerably faster. My humble suggestion would be to invest into a set of whiteline adjustable links for the front. Look up the part number on their website & then order it from FCP Euro. You'll get a lifetime warranty on them.

Or

You could get a front & rear set from Hotchkiss. I had them, but didn't have as much luck with them.

I really like my whiteline links in the front. Unfortunately, they don't make a link for the rear. I just ended up putting Meyle HD beefed up links in the rear.

I had Hotchkiss adjustable links from day 1.

[sle39lvr]

I replaced the front sway bar bushings with OEM ones.

Once I took out did not look worn at all even after 130K miles:


The knock is still there!

I would say it's less now. Still the front end feels a little sluggish. It's audible when going over small undulations at slow speeds. Sometimes going over bumps where both sides of the front is decompressed, it sounds like something is really loose under there.

Also the sound feels like it's coming from underneath the car, not from above...where the wheel well is.

Knock does not exist if I move the steering side to side rapidly. So what could this be?

[IllSic_Design]

Had a problem like this that I couldn't figure out, turned out it was my sway bar end links being a LITTLE loose. When I felt them by hand and tried to wiggle them with the car on the ground they felt nice and tight but it was only when I lifted the car off the ground and used a jack under each wheel to cycle the suspension that I could hear and trace the sound to the end links.

[sle39lvr]

Originally Posted by IllSic_Design

Had a problem like this that I couldn't figure out, turned out it was my sway bar end links being a LITTLE loose. When I felt them by hand and tried to wiggle them with the car on the ground they felt nice and tight but it was only when I lifted the car off the ground and used a jack under each wheel to cycle the suspension that I could hear and trace the sound to the end links.

So you shortened them?

[IllSic_Design]

No, I tightened the nuts that bolt it to the sway bar. The end link mounting nuts were slightly loose and was causing them to move around/knock in the sway bar.

[mweisdorfer]

Originally Posted by IllSic_Design

No, I tightened the nuts that bolt it to the sway bar. The end link mounting nuts were slightly loose and was causing them to move around/knock in the sway bar.

you can tighten it all you want; its not going to get rid of the knock. Your sway bar links are bad. They are connected to the top of the strut and the sway bar. Until you get at least adjustables in the front and shorten them up by at least 1" to 1.25" and or the amount you basically lowered the car in the front, you will have the knock. The Whiteline's come prefab 12.5" which is about 1" shorter than stock. So, there's not a whole lot you need to adjust. I posted a DIY on this. Take a look. If you8 decide to get adjustables in the rear, you have to add length.

[IllSic_Design]

Originally Posted by mweisdorfer

you can tighten it all you want; its not going to get rid of the knock. Your sway bar links are bad. They are connected to the top of the strut and the sway bar. Until you get at least adjustables in the front and shorten them up by at least 1" to 1.25" and or the amount you basically lowered the car in the front, you will have the knock. The Whiteline's come prefab 12.5" which is about 1" shorter than stock. So, there's not a whole lot you need to adjust. I posted a DIY on this. Take a look. If you8 decide to get adjustables in the rear, you have to add length.

Dude....... what are you talking about? Reading comprehension......

I have adjustable end links and there is nothing wrong with them. I don't have any troubles with my car at the moment, I was trying to help OP by pointing him to another culprit of clunking over bumps at the front end. Loose sway bar end links(I don't mean worn out, I mean they were not tightened up enough on the sway bar) are a known cause of clunking on the front end, plenty of threads on this.

EDIT: Also, if you have lowered your car and you get adjustable end links you need to LENGTHEN them compared to stock.

[mweisdorfer]

Originally Posted by IllSic_Design

Dude....... what are you talking about? Reading comprehension......

I have adjustable end links and there is nothing wrong with them. I don't have any troubles with my car at the moment, I was trying to help OP by pointing him to another culprit of clunking over bumps at the front end. Loose sway bar end links(I don't mean worn out, I mean they were not tightened up enough on the sway bar) are a known cause of clunking on the front end, plenty of threads on this.

my bad. My post was meant for the OP.... Sorry man

[IllSic_Design]

Originally Posted by mweisdorfer

my bad. My post was meant for the OP.... Sorry man

No worries, my bad too. Seemed like you were trying to correct me/tell me I was wrong.

[sle39lvr]

Originally Posted by mweisdorfer

my bad. My post was meant for the OP.... Sorry man

Ok as the OP, I am even more confused.

Just to clarify, I also have adjustable sway bar links. When the knock was first noticed, they were the first thing replaced.

As my next step, I am going to drive with the links deattached, to see if the knock is outside of swaybar/links.

[mpathic]

Use the //M3 bushings instead of the non-M bushings at the same bar diameter. They are two piece, with rubber molded within a pair of metal sleeves. Much firmer rubber and tighten up better than the non-M all rubber bushing or aftermarket urethane.
hth.

[sle39lvr]

So this issue still seem to be there.

Knock is getting worse. It's more present when it's cold, less when warm outside.

I jacked it up again, couldn't notice anything being worn or lose. Any ideas?

PS: This is after new sway bar end links and new sway bar bushings.

[gjm120]

Originally Posted by mweisdorfer

you can tighten it all you want; its not going to get rid of the knock. Your sway bar links are bad. They are connected to the top of the strut and the sway bar. Until you get at least adjustables in the front and shorten them up by at least 1" to 1.25" and or the amount you basically lowered the car in the front, you will have the knock. The Whiteline's come prefab 12.5" which is about 1" shorter than stock. So, there's not a whole lot you need to adjust. I posted a DIY on this. Take a look. If you8 decide to get adjustables in the rear, you have to add length.

I think it's the other way around - should lengthen front links the amount of the drop.

[mweisdorfer]

Originally Posted by gjm120

I think it's the other way around - should lengthen front links the amount of the drop.

The hole on the sway bar that the end link attaches to needs to be at 3 O'Clock position; So, the sway bar sits naturally, and it not stressed while the wheel is straight.

👎 nope!

https://www.e90post.com/forums/showthread.php?t=331670

[gjm120]

Originally Posted by mweisdorfer

The hole on the sway bar that the end link attaches to needs to be at 3 O'Clock position; So, the sway bar sits naturally, and it not stressed while the wheel is straight.

👎 nope!

https://www.e90post.com/forums/showthread.php?t=331670

Nope to what?
I'm lost or maybe just being dense today - see what I bolded in your post just above.

[mweisdorfer]

Originally Posted by gjm120

Nope to what?
I'm lost or maybe just being dense today - see what I bolded in your post just above.

Ya, now I see my mistake. I meant longer in front, shorter in back.

[gjm120]

Originally Posted by mweisdorfer

Ya, now I see my mistake. I meant longer in front, shorter in back.

I figured that just didn't want anyone to act on the wrong post.