Clunking sound when I hit a bump

[ard]

Originally Posted by Badsmerf

Why do you treat people so poorly?

Just a mild kick in the arse, to get you the help you need. Glad to see you have moved to a more precise style, citing parts by number!.....


IMO I dont understand how a strut assembly under compression can be 'compressed further' by hand...just shouldnt be possible. you can move the whole strut around, when attached to the wheel and the top released- but this isnt 'compressing'.


If you really can compress the shock, meaning the spring is not pressing the top and resisting a relative compression of the top hat down onto the lower mount, it isnt a strut issue-



IMO, a 'weak strut' will not make noise. It may need replacing, and it may drive better once replaced, but it isnt a source of noise.

[Badsmerf]

ard, you drive me crazy sometimes.... When the front end is jacked-up, the system is pretty extended. With the top nut is off, the strut shaft should be free to move. My concern, is that it was too easy to compress. Maybe I just have too much power...

[FunfDreisig]

ARD & Badsmerf,

I think the issue is the semantics of “compression”.

Once the top nut AND the wheel are removed, the strut assembly is no longer in compression. The spring is just floating between the Support Bearing Flange (#9) and the flange on the strut/shock. So moving the spring up off of the flange on the strut/shock, in order to replace the lower spring pad MAY require compressing the spring. But it may just require lifting the heavy spring up off of the lower spring pad (#4).

I agree that in and of itself and weak strut should not make noise. But a weak strut can put more impact on the upper and lower Guide Supports (#8 and 10) causing them to fail/disintegrate. When that happens there is play at the Support Bearing Flange (#9) that can cause the metal washer in the top of the dust shield (#6) and/or the large washer (#11) to hit the support bearing flange creating the clunk.

Funf Dreisig

[Toothbrush]

Just to through my two cents in, I had replaced my lower control arms and sway bar links, got it put in alignment per ard's suggested numbers and it felt great... until a while ago it started making a clunk that I couldn't figure out.

Turned out to the be the guide supports (upper part on passenger was mostly gone). I followed this DIY https://xoutpost.com/1107792-post1.html and even used the same type of spring compressor. No more noise or clunking, nice and smooth now.

1st strut was a learning experience, so took a couple hours going slow. 2nd one was about half the time. I picked up all new nuts and only replaced 7, 8, and 10 on the struts in the diagram on the first page:

10 - Upper Guide support 31336776390
8 - Lower Guide support 31336776389
7 - Additional shock absorber, front 31336771892

My clunk was coming from the right side (passenger) and was almost random. Sometimes bumps would cause it, sometimes not.

The spring compressor I used was "Macpherson Strut Spring Compressor Interchangeable Fork Coil Extractor Set" off of amazon and it worked great. I was a bit nervous after watching some videos of people using the hook type improperly, but this set never gave me any issues. (I think it's the same set used in the DIY link)

The only trouble I ran into was trying to get the Strut Mount (#2 in the diagram) off of the passenger side strut, and for some reason getting it back on the drivers side.

Did all this work yesterday, so glad it's done!


Edit: I forgot to mention, when I came back in from the garage my wife was like "are you done already?! that was fast!...." Six or seven hours start to finish (prep, clean up, quick run to the store for a 21mm socket included) = "fast"

[philly42]

Originally Posted by philly42

I'm getting a similar sound on the X5M over small bumps. Replaced last year was the thrust-bushing assembly and lower control arms. I was thinking it could be the upper strut mount/guide support, but the X5M design is different where it seems not to have the rubber/foam like standard X5s.

Maybe the rubber/foam is built into the amount and is not serviceable? I ordered new swaybar link and will see if that eliminates the clunk.

(Pics of X5 and X5M mount)

Here's an update on the knocking sound I was getting on the X5M. The tension strut ball joint was quite loose eventhough it was only a year old. Reused an old original arm that had a better ball joint and swapped out the bushing.
replaced the swaybar links.
Checked shocks and shock mount. The rubber inside the X5M's shock mount is not serviceable but appeared to be good...no cracking.

It rides great with no knocking sound.

[SF2000x5]

I wish I came across this thread before replacing swaybar endlinks.

Can this be added to a DIY thread if it isn't already?

[crystalworks]

Originally Posted by SF2000x5

I wish I came across this thread before replacing swaybar endlinks.

Can this be added to a DIY thread if it isn't already?

Sway bar end links are cheap, can cause a "clunk" type noise, and very easy to replace, worth a try before going after the strut assembly rebuild stuff if trying to piece meal the remedy. They have been in there awhile most likely anyway and could use a refreshing as long as you are doing the other stuff.

I typically rebuild the entire suspension on BMW's every 120,000 miles(ish) or when the first major component goes bad. This way I deal with very few annoying noises/shudders/etc related to the suspension through ownership.

[SF2000x5]

Yes, not expensive so I replaced them before replacing the guide supports in hopes of getting rid of the thump.

[josiahg52]

Originally Posted by crystalworks

Sway bar end links are cheap, can cause a "clunk" type noise, and very easy to replace, worth a try before going after the strut assembly rebuild stuff if trying to piece meal the remedy. They have been in there awhile most likely anyway and could use a refreshing as long as you are doing the other stuff.

I typically rebuild the entire suspension on BMW's every 120,000 miles(ish) or when the first major component goes bad. This way I deal with very few annoying noises/shudders/etc related to the suspension through ownership.

Not a bad plan. I'm coming up on 140k miles and so far so good (no clunks or noises and rides well enough) but I know it has to happen soon and I'll be in for the whole kit = $$$$

[crystalworks]

Originally Posted by SF2000x5

Yes, not expensive so I replaced them before replacing the guide supports in hopes of getting rid of the thump.

That's what I meant. I thought that was a reasonable course of action and the first thing I tried too before realizing the strut assembly needed rebuilding. Worth a shot.

Originally Posted by josiahg52

Not a bad plan. I'm coming up on 140k miles and so far so good (no clunks or noises and rides well enough) but I know it has to happen soon and I'll be in for the whole kit = $$$$

Yeah, just rebuilt the entire front end on the wife's diesel at 154000 miles after the bearing/sleeve on the strut mount finally completely tore away. Foam bushings were shot already. Cost for everything, including upper wishbones, was a little under $700. I can only imagine what a dealer would charge to do it.