clunking sound from front suspension after H&R spring installation

[PapaKlix]

i posted this in the DIY spring install so apologies for the cross-post, but i'm trying to figure this out and i know of at least a couple of other people who have a similar issue.

i installed H&R springs in my e92 m3 last weekend and there is a very noticeable sort of clunking sound on every bump coming from the front of the car only at low speeds. at first, i kind of thought i might not have shut the hood all the way. the speed threshold seems to be about 40 mph, above that the noise goes away. it was suggested to check the swaybar arm connection to ensure it's torqued to spec, which it is (i used blue loctite as well). i'm hoping someone in this forum has any ideas?

[THE TECH]

Possibly you didn't seat the springs correctly? Also check the nuts on the top holding the perches as well as the center nut that tightens the shock.

[Richard@M-World]

I would also check the strut top nuts. Can you take some pictures?

[PapaKlix]

Originally Posted by THE TECH

Possibly you didn't seat the springs correctly? Also check the nuts on the top holding the perches as well as the center nut that tightens the shock.

i thought the same re: spring seating, but i did it twice and both times it felt pretty secure. unless there is some sort of hard lock click that i'm unaware of, they felt pretty solid going back. i did it twice too, same result.

Originally Posted by Richard@M-World

I would also check the strut top nuts. Can you take some pictures?

i didn't remove the nuts that attach to the strut tower brace, just the center nut that tightens the shock. that one is kind of tricky because torquing it requires holding the nut and loosening the 10mm head of the shock. 47lb-ft is not a lot of torque and the wrench didn't actually pop indicating the proper resistance had been met, but i was worried about damaging the shock and wasn't sure if my wrench would pop appropriately in the loosening direction.

i can most definitely take pictures, the car is at the body shop now having the reflector holes shaved so i'll do that when i get it back.

i was hoping that the fact there is no sound at higher speeds would be an obvious indicator of what the problem is, does the center nut on the strut being loose make sense that at higher speeds there would be no sound?

[JAJ]

I think that just because you can't hear the clunk doesn't mean something isn't loose.

Dropping the front struts out by undoing the center nut while leaving the strut upper mount in place is, in my opinion, the riskiest and most error prone way to do this job. It's not that it can't work if you do it this way, it's just that it's more likely to lead to problems than other approaches.

The strut mount and the thrust bearing inside it have to be re-assembled correctly or all kinds of problems can arise. Re-assembling it blind by lifting the strut up into it could cause misalignment somewhere in the internals that could easily feel like everything is done up tight while it's actually still loose.

So, if you're positive that the swaybar links are done up tight and they're not the source of the noise, then you're going to have to take each side apart again and make sure the strut tops are intact and that the bearings rotate smoothly and quietly.

This time, though, don't undo the strut center bolt. Undo the three nuts on the top (the brace will stay put without them), the bolts for the swaybar links and the various bits of wiring and brake lines, but leave the top on the strut. There's more than enough room to swing the complete spring and strut assembly out from under the fender.

Once it's out, compress the spring, undo the center nut and check the strut mount for proper operation. Reassemble them in place and feed the strut back underneath and do all the nuts and bolts back up. This time around, it should be quiet. By the way, some torque wrenches allow you to use them backwards by pushing the drive pin through to the other side. If you can rent or borrow one of those, it would be best. You can also use a specially made strut wrench that takes a torque wrench properly. I have one and it makes the whole job really easy.

[PapaKlix]

Originally Posted by JAJ

I think that just because you can't hear the clunk doesn't mean something isn't loose.

Dropping the front struts out by undoing the center nut while leaving the strut upper mount in place is, in my opinion, the riskiest and most error prone way to do this job. It's not that it can't work if you do it this way, it's just that it's more likely to lead to problems than other approaches.

The strut mount and the thrust bearing inside it have to be re-assembled correctly or all kinds of problems can arise. Re-assembling it blind by lifting the strut up into it could cause misalignment somewhere in the internals that could easily feel like everything is done up tight while it's actually still loose.

So, if you're positive that the swaybar links are done up tight and they're not the source of the noise, then you're going to have to take each side apart again and make sure the strut tops are intact and that the bearings rotate smoothly and quietly.

This time, though, don't undo the strut center bolt. Undo the three nuts on the top (the brace will stay put without them), the bolts for the swaybar links and the various bits of wiring and brake lines, but leave the top on the strut. There's more than enough room to swing the complete spring and strut assembly out from under the fender.

Once it's out, compress the spring, undo the center nut and check the strut mount for proper operation. Reassemble them in place and feed the strut back underneath and do all the nuts and bolts back up. This time around, it should be quiet. By the way, some torque wrenches allow you to use them backwards by pushing the drive pin through to the other side. If you can rent or borrow one of those, it would be best. You can also use a specially made strut wrench that takes a torque wrench properly. I have one and it makes the whole job really easy.

hey man, thanks so much for such a thorough and thoughtful response. i will try this as soon as i get the car back from the body shop. do these 3 bolts need to be replaced when removed? i feel like i've read somewhere that they do.

before i put the assembly back up and on the strut mount, i was able to spin the rubber around freely and the bearings felt very smooth. is there a good chance that i have damaged them?

[JAJ]

Originally Posted by PapaKlix

hey man, thanks so much for such a thorough and thoughtful response. i will try this as soon as i get the car back from the body shop. do these 3 bolts need to be replaced when removed? i feel like i've read somewhere that they do.

before i put the assembly back up and on the strut mount, i was able to spin the rubber around freely and the bearings felt very smooth. is there a good chance that i have damaged them?

The 3 nuts and bolts will be fine. The issue is that damage might occur if the strut upper mount and the bearings that it contains are out of line. That said, this stuff is made really sturdy in the first place, so chances are good that if you just get it put back together right all will be well.

But, like I said, before you go to the trouble of taking it apart again, make sure first that the sway bar mounts (and all the other bolts and nuts down there) are properly done up.

[PapaKlix]

Originally Posted by JAJ

The 3 nuts and bolts will be fine. The issue is that damage might occur if the strut upper mount and the bearings that it contains are out of line. That said, this stuff is made really sturdy in the first place, so chances are good that if you just get it put back together right all will be well.

But, like I said, before you go to the trouble of taking it apart again, make sure first that the sway bar mounts (and all the other bolts and nuts down there) are properly done up.

so i tried again and no luck, the sound is still there. does it matter that i didn't disconnect the sway bar link on the shock side, but rather directly on the sway bar itself? the end mounted to the shock was much more difficult to get proper access to. anyway, i disconnected the shock mounted sway bar link on the driver's side but did the other on the passenger because it was such a hassle getting the top one off.

i tried your recommended approach too - taking the whole assembly down and compressing the springs at that point. the bearing assembly slides very smoothly and does not appear to be assembled improperly.

at this point, here's what i'm thinking - remove the sway bar links entirely and drive very carefully up and down my street to try and isolate the sound. right now i just feel like i'm guessing at what the noise is and that not knowing is driving me nuts. anyway, there's no risk of damage if i do this right?

[SlamMan]

I just fixed a clicking sound this afternoon after a camber plate install myself. It turned out it was a lose nut and bolt on the top connection of the sway bar link that would click every time it shifted the direction of load. It went away as soon as I tightened the top nut. It was a pain for sure to get a wrench on the back side to hold the bolt while you tighten the nut.

Obviously I can't say your issue is the same but if it is you should be able to recreat and hear the clicking by pushing and rocking the car side to side while it's parked. The easiest place to get leverage and rock it is to open the door and push on the car on the side of the roof/top of the a pillar. Have a friend rock the car while you get down and try to hear where the sound is coming from. You might even be able to get down on the ground and put your hand on the sway bar and feel the clicking. If you can't hear the sound doing this it's probably not the same issue.

Like I said, this may not be the same issue but I wanted to share my experience since I just did this today.

On another note, personally I've had zero issues taking the suspension apart by taking the shock rod nut off and dropping the strut down out of the bearing.

Good luck.

[pbonsalb]

A bad swaybar link will make a clunking sound. Maybe you damaged one when removing them. Typically you have to use a thin flat wrench to hold the ball joint while you remove the nut. Otherwise the balljoint spins and that may be what happened here.

[PapaKlix]

Originally Posted by pbonsalb

A bad swaybar link will make a clunking sound. Maybe you damaged one when removing them. Typically you have to use a thin flat wrench to hold the ball joint while you remove the nut. Otherwise the balljoint spins and that may be what happened here.

wait a min - when i was trying to remove the first one, i turned it several rotations before i realized i needed to wrench the back. i was still able to get it off and back on but are you saying the joint could be damaged? do you think it's damaged and just needs to be replaced?

[SlamMan]

I'd say it's more likely still loose than damaged.