Clunking sound when I hit a bump
 

HI

Whenever I hit a little pothole on road, i get some loud clunk on right side of car, not sure if its front or back or both. Could it be shocks or something else I should be looking for? My car just reached 100K miles, X5 4.8 2009.

This is the main symptom of a very common failure. The clunk is almost certainly the result of the failure of the orange cushions (aka Guide supports) on one or both of the front shock struts. You can check this by opening the hood and looking at the top of the struts for an orange powder.

FWIW I spent a lot of time diagnosing a similar clunk that I thought came from behind the driver. But eventually I looked under the hood and found the real culprit. Here are links to two threads with the gory details.

https://xoutpost.com/bmw-sav-forums/...unk-trunk.html

https://xoutpost.com/bmw-sav-forums/...build-diy.html

Funf Dreisig

Thank You

So I was told is the front lower control arm, is there any difference between OEM and other brand? Seems like OEM is double the price


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just a thought but last time i did my whole front end replacement with the cheapest parts for my e36 i started to rattle again within a year and a half. replaced it with oem its been 5 years since its still nice and stiff.

Thanks for the heads up

In most repairs the labor exceeds the cost of the parts. I’m usually saving quite a bit by doing my own labor. So I don’t chince on the parts. I look for a good price on OEM parts. Often I can match the OEM, that BMW uses for that part, at roughly half the cost of BMW’s part.

Funf Driesig

Yeah my money would be on tension arms. I just put a set of Febi on, I expect them to last 40K miles. Be sure to replace the one-time-use fasteners. The torque spec is important to achieve proper bolt stretch. Found in TIS.

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)

Funf, I have a question. How hard is it to compress the strut shaft? I've had this little rattle and replaced the lower foam piece by compressing the strut enough to slip it in before the shaft expanded again. It took some effort to push down, but seemed like it should be much stiffer. My foam pieces are fine. Replaced end links and tension arm, thinking about trying lower control arm next. Just haven't had the time for a few months.

I have the same problem on the same side on the same x5 4.8 lol I replaced the lower front control arm and same shit also the stoppers on the struts and compressed the spring same shit! Noise clunk. Next upper control arm or stabilizer . Let me know if you fixed. If this doesn't work new tires next

It’s a little hard to describe in words. But the photos are in this thread

https://xoutpost.com/bmw-sav-forums/...build-diy.html

The front springs are pretty stiff. I used a brand new spring compressor (i.e. well lubed) and a 1/2 ratchet.

https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

One end of the spring compressor was in a vice at table height. As the spring compressed the effort increased considerably. Near the end I had to hold down on the strut as I pulled up on the ratchet.

I assume the “lower foam piece” you replaced was #4 in the parts diagram. If so…. How did you compress the spring? Did you cut it to slip it around the shock?

Funf Dreisig

I didn't need to compress the spring. Take off the nut when wheel is on the ground. Jack it up, take off the wheel. Then, I was able to compress only the strut by putting my Allen in and compressing it enough to slip the new one in underneath. I just cut the old and pulled it out.

I'm just wondering if the strut should be that easy to compress. Maybe it is my faulty part. You had new struts, how stiff were they? How about the old ones?

Wow. 'Your bad part'????

Funf is using pictures and part numbers to be very precise about a complex collection of components.... You are using loose words, refering to parts as 'one', an 'allen'... Compressing 'only the strut' ....etc....

You don't need pictures of yours...there are hundreds of part blow ups online, even with numbers....pretty easy to use one and refer to these numbers.....

I didn't remember asking you, or your nasty tone... I obviously have a bad part somewhere in this suspension system. If I need to be more precise for clarification I will. Why do you treat people so poorly?

When you loosen the nut in the engine compartment (at the top of the strut) with the wheel on the ground. You are using the X5 as the spring compressor. If you later remove the wheel you have essentially disassembled the strut/spring combo. There are several problems with this procedure…

1 - you still can’t see/inspect the condition of parts number 7 or 8 in the parts diagram (that Philly42 posted)
2 - you can’t be sure that the spring re-seats correctly into part 5 when you let the X5 back down.

In the thread I linked, you can see that the original shock absorber was shorter than the Bilstein replacement. I think that this difference in length was not by design, but rather due to wear. Basically, at rest the old shock was just hanging there. So it didn’t begin absorbing the shock until the wheel had already started upward. In contrast the Bilstein was already under some compression, resisting upward movement even at rest.

In the same thread you can see that the extra length of the Bilstein meant that the flange on part #1 (the strut/shock) was not touching part #4 or the spring when I started tightening the nut at the top of the strut/shock. So if you had to pry the flange down to insert part #4, your struts/shocks are probably “shot”.

I would replace both front struts/shocks and parts number 7, 8 and 10. That’s what I did. And our 2009 X5 35d now drives like a loaner :)

Funf Dreisig

OOPs my bad. I thought I had posted this photo in the linked thread but…


The attached photo compares the length of the org strut/shock to the new Bilstein. Essentially when I installed the Bilstein I pre-loaded it by roughly 1.5“ before installation on the X5. Where it got loaded even more by the weight of the X5.

Funf Dreisig

You are right, I could not see the condition of part 7. I replaced the "doughnut" part 8, but it really wasn't in bad condition. Part 10 on the top of the assembly was perfectly fine, with almost no wear. Since I left the bearing support flange connected, I didn't have to mess with the spring at all, so the alignment shouldn't have changed. I simply pushed the shaft of the strut in far enough to slip the new doughnut in, then guided the shaft back through the bearing support flange and reassembled. I was going for a cheap and easy fix... didn't work this time.

If the culprit is a weak strut, I will replace the parts you listed. From what I've read, if you do one side, you should do both. Just been trying to verify before I spend the cash and effort. If I shouldn't be able to compress the shaft that easily, that will be enough to convince me.

Definitely a difference. How much were they and where did you get them?

I purchased both front struts/shocks (Bilstein B4) and part numbers 7 and 8 (BMW original) from ECS Tuning. The all up bill was $378.20.

I bought both parts #10 at a local dealer, because they were on back order at ECS Tuning and I want to get the job done that weekend :)

FWIW I believe that the failure of the Upper and Lower Guide Supports (parts #8 & 10) are due to a combination of age and the wear/tear on the strut/shock absorber. In other words, as the strut/shock wears out it transfers more impact onto the Guide Supports. Eventually they get pounded enough to disintegrate into the orange power. Think -- Canary in the coal mine.

Funf Dreisig

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!.....:thumbup:


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.

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...

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

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" :rofl:

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.

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.

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

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 = $$$$

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. :thumbup: Worth a shot.

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. :yikes: