help me track down a suspension rattle
 

This one has me stumped so far. Would welcome any suggestions.


'07 X5 4.8i. Rattling noise from left front when going over sharp bumps or stutter bumps. Rattle only when left wheel hits a bump - no sound when only right wheel hits a bump. To me it sounds similar to rattles from sway bar end links or strut mounts.


Parts replaced recently:

• sway bar end links: 32K km
• shocks, spring perches, bump stops: 17K km
• tension struts: 13K km
• lower control arms: 10K km
• inner and outer tie rods: 4K km
• L upper strut mount: 2K km

Here's what I've done so far:

• secured L rocker cover, inner mount is solid
• no play from wheel at 3/9 nor 12/6
• no play in upper wishbones, bushings are firm
• no play in any bushing (crowbar) nor ball joint (big jesus pliers)
• disconnected sway bar end links - noise still there
• tapped around everywhere with a mallet, including under the hood

I'm going to buy one of those remote microphone kits off Amazon. Any ideas on what I can try next?

Strut failure?

That's kind of what I've been suspecting. The only shocks I could get at the time were KYB (long story). There are no leaks, and handling doesn't seem to be compromised, but I'm wondering if something let go internally.


Ordered a Steelman Chassis Ear set today. Will hook it up later this week.

might be the strut mount bushings.

#8 and 10

https://xoutpost.com/attachments/x5-...p-x5-mount.png

Definitely have a look at 8,9, and 10 of they have not been replaced in your ownership.

7, 8, 10, and even 11 were replaced when I replaced 9. So, all good up top. That's why you see 9 replaced only 2K km ago in my list - I suspected strut mounts also. The old one that I removed looked basically brand new. Bushing was equivalently stiff to the one I replaced it with, so that turned out to be a waste of time and money.


Remote microphone should be in my garage this week, so I hope to be able to try it out this weekend. This one really has me stumped.

Do you have active suspension?

Mine has sport/active suspension and I have a good feeling the active suspension components have some play.

The front suspension tends to make a clunk on small pot holes.

should not, at all.


Have you diagnosed or just assumed it must be the 'active' stuff?

No. Sport and self-leveling suspension (note: this combination not available in USA, only Canada), so regular non-electronic shocks front and rear.


It's probably going to end up being a failure of some part that I've recently replaced, as I've replaced virtually everything both front and rear.

Guessing it’s active stuff. All control arm and joints were replaced but this is your thread so let’s figure out what’s going on with your car haha

When did you notice the noise? Did you notice the noise before replacing all those parts?

Also curious to know what makes your suspension sport if struts are not electronic.

The noise developed about 3K km ago, give or take. Since I hadn't yet replaced the strut mounts, I figured that would be it. Nope. Then I noticed that my rocker panel covers weren't properly secured, so I figured it could be those things bouncing around. I fixed that, but the rattle remains.



The sport suspension option S226A (not adaptive drive S2VAA) involves stiffer springs, different shocks, and a larger sway bar with matching bushings. IMHO, this is the wrong vehicle for sport suspension - I would rather have had regular, but then I would have missed out on the sport steering wheel and black headliner of the sport package.

While doing some front lower control arm work.
I noticed my brake heat shield was loose.
One of the bolts had rusted through. A larger washer fixed the problem.
I will hunt for some replacements, but this will get me trough the winter.

Mine had rusted through also. It wasn't rattling, but was rubbing against the rotor. I replaced the backing plate, and the rubbing went away but the suspension rattle was still there.



I'm 80% done replacing the shock with a Bilstein B4, and will know soon enough if that was the culprit.

Ugh, no luck. I replaced the shock, and the rattle is still there. All front suspension components (except springs, sway bar, and sway bar bushings) are new. Everything is properly torqued, all new bushings and ball joints seem to be OK.



When using the remote microphone tool, the rattle was most pronounced at the top shock nut, and somewhat less at the upper wishbone ball joint retaining bolt/nut. Virtually no rattles anywhere else. The tricky part is that everything is connected together in one system, so noises can travel to adjacent components.



I'll keep digging around with the microphones. This vehicle is killing me.

I would take a look at the left tension strut for play. Could be defective or prematurely worn - this happened to someone on this message board iirc.

Also, which brand did you go with?

I’ve only had my lemforder tension struts for about 20,000 miles/3 years but I think one of the bushings have some play so I’m probably replacing them soon. Good thing I bought from FCP with lifetime warranty.

I believe I used Mevotech Supreme for the tension struts, lower control arms, and upper wishbones. I usually prefer Lemforder suspension and steering parts but they weren't available at the time from RockAuto.


The tension struts look OK to me. No play in the ball joint, nor excess movement in the big bushing at the front. The sound is a definite rattle when going over stutter bumps. In my experience when the tension strut bushing gets soft the vehicle will wander and feel loose, and sometimes clunk when braking. None of this is happening in my case - handling is tight.


May be a few days, but I'll post results from another round of microphone tests.

any luck?

Haven't got around to it yet. Snowed where I am, so I was busy putting winter tires on the vehicles last weekend.

I'm going to try again this weekend. I'll focus for now within the engine bay (easier), connecting the microphones to the shock nut, strut brace, windshield wiper transmission, and anything else which might rattle. Will let you know how it goes.

Performed a few microphone tests today. It can be tricky to identify where the rattle is coming from, as everything is connected together.

Test 1: under hood only:

• shock nut (rattle)
• strut brace
• wiper assembly
• brake booster

Test 2: under hood and in wheel well:

• shock nut (rattle)
• strut mount nut
• strut tower
• lower rearward control arm inner (faint rattle)
• strut holder (rattle)
• spring

Test 3: in wheel well:

• tie rod ball joint
• lower rearward control arm inner mount (faint rattle)
• thrust arm ball joint
• lower rearward control arm ball joint (loud rattle)
• lower rearward control arm to strut holder (faint rattle)

So it looks like the most likely culprit is the lower rearward control arm ball joint. If so, this is disappointing as the part was replaced not long ago. I can't detect any play with a pry bar or large channel locks while the vehicle is on jack stands, and everything is torqued properly. Before I order this part again, any advice on how to test it? Maybe on ramps with load on the front wheels? Remove it?



There was some lateral play in the axle CV joint. I could "rattle" it a bit by moving it in and out. The other side had identical play, so I don't think this is it.

re: control arm aka tension strut....when it was replaced was it tightened UNDER FULL LOAD?

If not, the resulting 'twist' and load, can result in failure in a month or two

The control arm I referenced above was not the forward tension strut, but the lower rearward control arm - the one beneath the strut holder. That being said I torqued all bushing fasteners at normal ride height position by jacking the wheel up to the height measured when the vehicle was loaded. Also, I suspect it is the ball joint which has failed and not either of the bushings on that control arm. The ball joint can be torqued at whatever position, though I do torque them all at ride height.


That ball joint looks fine to me - I can't detect any play. I'm wondering if I have to have the vehicle loaded to detect play? Ball joints can be weird sometimes.

If the ball joint failed that quick..super weird.

This. Effing. Car. Is. Killing. Me.

Replaced the lower rearward control arm today. Ball joint put up a multi-hour battle. Rattle noise is still there. I'm wondering if it could be the CV joint, but there's no way I'm going to replace an axle unless I know for sure that's it. There is some lateral play, and I can make it click when I rattle it back and forth, but both sides seem about the same.

Before I push this thing off a cliff, any ideas? All of the suspension is basically new, and there's no play in anything.

Upper wishbone been replaced? Didn't see it on your list. They aren't known to fail... but who knows...

Yes, upper wishbone replaced. Only thing not replaced is the spring. Everything else is new.

all rubber mounts, bushes within the strut/spring assy?

I just had that done to mine. New struts and the whole nine yards. She runs perfectly now.

Yes, everything except the springs.

Dealing with same issue...I think
 

Lightly Toasted,

I think I am dealing with the exact same issue as you....Maybe

First, I'd like to clarify if the noise is a rattle, or more of a clunking?

Everything you have described seems to be exactly the same as what I'm dealing with, except my noise is a clunking... Also had a chirping noise associated with this. Let me explain a little more...

Started off that I was getting a clunking noise when going over bump to hard, (in particular pot holes and speed bumps). Eventually, this progressed to the point that there was a chirping noise. Eventually, I tracked this down to the right front upper strut mount. It drove me crazy for 2 weeks...thought it was coming from something rubbing inside the dash.... I finally figured it out when I open the hood and got on the passenger runner board and bounced up and down and hard as I could. I was able to to see the washer move up and down and rub against the tower and chirp. The strut mount had failed.

I replaced the strut with a new one...

Looking at my pic you can see my screwdriver pointing to the strut tower where the paint has been rubbed off and is silver. This is where the washer would rub against the tower when going over bumps big enough to cause the strut to bottom out, and make a chirping noise.

Replacing the upper strut mount fixed the problem.....for about a week or two, then the clunking is back!!! The new strut mount failed! I assumed either missed something with the install, or maybe didn't quite get the upper nut tight enough, or ...maybe the part was just defective. So, I took back the "defective" one and replaced it... FIXED!!! ... for 2 weeks..... UUUGHHHH

Now the clunking is back again!

There's no chirping, just the cluncking. ...

Here's what I think at this point
 

Here's where I'm at ...

I feel like the clunking and chirping go together, but not positive. Her is my theory on that (which doesn't mean much, LOL). When the strut mount goes out initially, you will hear the clunk when the strut bottoms out over bigger bumps. After awhile of this happening, eventually the rubber mount wears a large enough hole to allow the strut to move enough to the point that the washer will rub on the flange of the tower.

Here is the pic of the original strut mount I replaced. You can see that the whole is worn to the point it allowed enough play for the washer to rub against the tower.

Here is what the original mount looked like after I took the washer off.
You can see how the strut is leaning to the side

Here is what I know

Bought 6 months ago in like new condition
2011 e70 X5 35d

Started hearing clunking noise a little about 3 months ago,
Clunking noise progressively got worse (from, "is this noise new, or always been there", to "yae, this deff is not supposed to sound like that")
Started to hear chirping noise as well....

Changed right upper strut mount, and clunking and chirping noises went away

2 weeks later clunking noise emerged again.

Replaced upper strut mount again, and clunking noise went away, I thought.

Now 1 week later, wifey is telling me she hears the clunking noise again...but, only over bigger bumps, and only if she is going really fast. Yes, that's how she said it to me!LOL

I stumbled onto this thread yesterday and found this diagram.
It does appear that I missed replacing #10 the foam washer, spacer, or whatever it is. I did replace #8, but missed #10. When removing strut for the 1st time, the wear must have gone on long enough to have completed disintegrated the original one, and I never realized it was missing.

I would not think that would be crucial enough, so that the replacement wore out in 2 weeks, but it wouldn't surprise me.


SO.....LightlyToasted

Thinking.....maybe it's your upper strut mount, even thou you did replace it??? maybe???

I have replaced everything except the spring. When I replaced the strut mounts they showed no signs of wear. The only part which clearly needed replacing was the bushing at the front of the thrust arm - all other parts were basically fine, but I replaced them anyway.


The noise is a dull rattle, not a single clunk. It only happens when going over a bump (so I would normally suspect a suspension issue), but I'm beginning to suspect the inner CV joint. I can pull the axle in and out a bit, and it makes a clunk when I do so. Usually CV joints make noise when decelerating which is why I looked at suspension first. I can now make a slight clunk when "stutter stopping" at low speed.


Anyone know how to diagnose an inner CV joint?

A **long** time ago I recall a thread where someone had a noise that was traced to a bad few welds in the body/strut tower area. I think. Anyone else recall?

Long shot... But did you tighten number 3 enough? Not sure how much movement would be there if it were "loose." Long shot... And you've done the job twice so unlikely you didn't tighten it both times.

Edit: wouldn't hurt to check torque values on all the fasteners involved actually. Fairly common to have to go back in after a week or two and retorque.

I torqued all fasteners (including #3) with a torque wrench. The first thing I did was to retorque everything. Nothing had come loose. There is no evidence of the shock coming loose from the lower holder, like paint scraping or a dust line. Also, it took quite a bit of prying that holder open to replace the shock.



While we're on the topic of the lower holder, one thing that is interesting is that there is a slight taper at the bottom to receive a rounded-bottom shock body. The OE and KYB shocks have this taper, but the Bilsteins do not. The Bilsteins sit firmly a few mm from the bottom of the mount. I first noticed this when comparing the shocks side by side on my work bench - at first the KYB seemed slightly longer. Note - the rattle was present for both the KYB (tapered) and Bilstein (not tapered) shocks.

I think that the stabilizer bars on my e53 and my e70 have a tendency to make squeaking and/or croaking noises going over speed bumps. Never got around to putting lube on them to see if it would help, as it mostly occurs in the mornings getting my daughter to school. Nor do I know if doing so would be good, bad or indifferent but it would be easy to squirt some wd-40 in there and remove it if need be.

This vehicle continues to make me cry.
Rattling symptoms have gotten worse, and have developed a new companion symptom. If I do a series of stutter stops and starts there is a clunk which sounds identical to the clunking/rattling when I go over stutter bumps. It sounded to me similar to what a loose brake pad would sound like, or perhaps a worn CV joint with radial play.
I verified that the caliper and carrier is secure, and that there is no play in the pads or caliper. I also replaced the CV axle. Both symptoms the start/stop and stutter bump rattling are still there.
When I have the vehicle on jack stands, and I rotate the wheel back and forth quickly, I can hear the clunking. I can even get it to happen with the wheel off by rotating the brake rotor back and forth quickly. Kind of hard to tell if the sound is coming from the wheel side or the diff side of the axle, but it's definitely in that area.

I have a wild a$$ theory that I'd like to run by you guys. When I was replacing the axle the outer splines came out of the hub with virtually no pressure at all - I pressed it out with my finger! Normally they're in there very tight with almost a press fit, requiring a press tool to press the axle out. New axle went in effortlessly, sliding out to full extension with zero effort. I'm wondering if the PO replaced the bearing with an inferior part with really loose tolerances, and the axle is slopping around in the bearing splines. What do you think? Any way to tell if this is the case?

I went through a similar nightmarish front clunk chase ...... thought it was the radiator (clunk was replicable just with tap-braking), checked brakes/pads, radiator, engine mounts, etc etc etc

https://xoutpost.com/bmw-sav-forums/...tor-loose.html

After weeks of chasing the culprit, replaced lower control arms -helped but did not completely removed the clunk- I believe the issue is still the #8 part in the diagram which plan to address soon.

#8 and #10 can create noises when they deteriorate. One thing I didn’t see mentioned yet is engine mounts. Worn engine mounts can creak and clunk.


Sent from my iPhone using Xoutpost.com

Would worn engine mounts clunk when tap braking, and over stutter bumps? My clunk is definitely coming from the driver's side. I'll see if I can get an inspection camera in there to take a look at it. I may also hook up a remote microphone to it.

In the meantime, I'm going to replace the hub/bearing assembly this weekend. I can make a fainter version of the clunk happen by quickly rotating the wheel back and forth, similar to tap braking. Previous microphone tests with a mic near the hub were very loud, but I've also learned that vibrations and sound travels through related parts.

I believe you replaced a number of items already but below are some posts with similar 'clunking' issues that I researched when I was troubleshooting mine.....there is great material here - just read through those.....

https://xoutpost.com/bmw-sav-forums/...left-side.html

https://xoutpost.com/bmw-sav-forums/...ks-x5-e70.html

https://xoutpost.com/bmw-sav-forums/...-hit-bump.html

https://xoutpost.com/bmw-sav-forums/...ssemblies.html

https://xoutpost.com/bmw-sav-forums/...end-clunk.html

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

https://xoutpost.com/bmw-sav-forums/...ive-drive.html

Several threads pointed to the #8 and #10 as primary culprits as well as sway bar links and the lower control arm - engine mounts was my "last" item to test (less likely to be the cause)

1. #8 and #10
2. Sway Bar Links (and Sway Bar Supports)
3. Lower Control Arms
4. Loose Brake Pads
5. Front Axle / Bearing / Diff.
6. Loose radiator
7. Engine Mounts

.....

I've eliminated 1-4. On to #5-2 now. Will replace bearing assembly tomorrow, and check 6 and 7 while I'm at it. I really hope it isn't the diff...

Replaced bearing and hub assembly today. The clunking remains. The bearing was dry and needed to be replaced, but really that's just what I'm telling myself to keep from pushing this thing off a cliff.

Thanks for the advice, and apologies to the forum, but I concede defeat. I'll take it in to an indy Monday morning.

For those of you who want to replace a front bearing assembly, a couple of tips:

• don't cheap out on the bearing. SKF and FAG are good brands
• you need to replace the 4 TTY bolts holding the bearing assembly to the swivel bearing. There's more than one variant of OE bolt for this purpose, so be sure to get the correct bolt which matches the thread pitch (either 1.25mm or 1.5mm) of the new bearing assembly. My SKF was 1.5mm. To remove the old bolts I needed an 12-point M12 "triple-square" male bit, and the new bolts required a T60 torx bit. There's not much room around the outer CV joint, so a long bit is preferable, and it helps to remove the sway bar end link to get to the forward ones.
• if the axle shaft doesn't go in far enough to get the axle nut on, you'll need an M27 axle puller. You can get a kit on Amazon for about $60.

Sorry to hear.


Please update when the solution is found, thanks

As a last gasp, I double checked a couple of things. I checked the brake pads for play. With the caliper removed and the pads hanging from the caliper mount, there is a very small amount of play, say 0.1mm, on both pads. I can make a slight rattle with this small amount of play. How much play is allowable? Do they basically need to be a slip fit? The inner pad fits snugly in the caliper piston. When I attach the caliper and anti-rattle clip there's zero play. The caliper slide pin rubber bushings are solid with no excess play. I really don't think this is it.

I was also able to hear a faint clunk from under the vehicle when rotating the front wheels back and forth. I traced the noise to the rear of the front drive shaft at the transfer case. There's quite a bit of play at the rear universal joint when I move the shaft up and down, and some radial play in the rear u-joint and a slight clunk when I rotate the front drive shaft. I kind of suspect this is the culprit - it seems like the rear u-joint has too much play, or perhaps the play is in the transfer case. Any way to tell for sure?

Did someone hear or BF drop a front driveshaft looking for a noise? Just for a few hundred yards, to diagnosis. deroy? Im thinking it was someone in the Netherlands....

The TIS seems to suggest that any play at all is bad. Mine has significant play, especially laterally and radially.


I wonder if I can rig up a GoPro in that area...

Would that make noise when tapping the brakes though? All the U joints I've replaced were identified by vibrating or a single clunk, not from small bumps.

We might not have the same problem, but it sounds very similar. I haven't replaced all the bump stop in the strut/shock assembly, but have replaced the tension arm, end links and both doughnut bump stops. The sound started on the drivers side only, but it is now very much on both sides. I ignored it for a while, but I will be actively chasing it this spring. Hopefully you can find the answer before I have to go through a bunch of parts lol.

I can recreate the clunk by hand by rotating the front drive shaft through its radial play, so I'm confident that loading and unloading the drive train (via tapping the brakes) would do the same. As for the clunks caused by bumps, it clunks quite a bit by pushing it up and down (lateral play). I'll see about taking some video of this play.

At any rate, I'll know soon enough. In an effort to continue to throw money at this problem and single-handedly stimulate the economy, I'm picking up a front drive shaft today which by some miracle is in stock at a local parts store. The diagnosis procedure in the TIS is pretty clear about the u-joints not having play, so may as well replace this thing to see if it helps.

Would be great if you could put up some videos of the driveshaft play, ideally before and after.. I’ve got what I think it massive driveshaft play, so would be good to know if it is normal or not.. and If its the potential cause of a clunk I’ve got going on.

Got the part today. Hope to be able to install it tomorrow. Will take some videos along the way.

I don't know what years but some driveshafts were recalled for premature u-joint failure.

Yeah, I emailed bmw, and mine isn’t on the recall list, But it has me a bit concerned! I got under the car and just took a video (found a friggin oil leak too..) but I have no idea how to upload it.. I could email it though..

Mine doesn’t appear to be the u joints, more the yoke that goes into the transfer case, heap of movement!

Mine also. I'm not sure if the culprit is the u-joint or the connection to the transfer case, but the TIS diagnosis procedure seems to blame the u-joint / drive shaft if there is play.

Well, I got the front drive shaft replaced. That was a brutal job. It's easy enough to unbolt the drive shaft from the front diff, but a frame cross member prevents you from dropping the front of the shaft so that it can be pulled out from the transfer case. I made a tiny bit of extra room by unbolting one exhaust mount to allow the pipe to be moved a slight bit, and devised a hard-to-explain scheme to work the front u-joint under and behind the guibo so that there was enough room to pull the shaft from the transfer case. Installation of the new one by the reverse process was even harder.


And it did not fix the clunk :banghead:


The u-joints on the new shaft were smooth and somewhat stiff as you'd expect. The u-joints on the old one were floppy, but didn't really have any notchiness or lack of smoothness. The up/down lateral play was significantly reduced, but not eliminated. I think that play is in the transfer case. Any radial play seems like (normal?) gear lash at the front diff or transfer case - if you hold the guibo steady like the TIS suggests there's no radial play.



I apologize but I was not able to take any video. I couldn't get my camera and tripod under the car, and I had a time limit.


Not sure where to go from here. I'll maybe compare the brake pad play to the other side, but I'm basically out of ideas.

1. Did you rebuild the strut yourself? If so, did you make sure that the correct stud bolt was flush with the positioning pin that goes into the spring holder groove?

2. Did you inspect the functioning of the brake caliper? Is it completely free of rust, free to move, and the boot is intact?

Yes, I rebuilt the strut myself. There was no locating stud on either the OE shock nor the KYB replacement, nor the Bilstein replacement, IIRC. Yes, that's right - I've actually rebuilt it twice trying to find this rattle. The OE and KYB have a convex bottom which matches the profile of the strut holder, whereas the Bilstein does not. There's no movement of the shock in the strut holder.


Yes, yes, yes, and yes. There is a very minor amount of play between the pads and the caliper carrier which I'm going to compare to the other side, and maybe swap pads from side to side. I replaced the pads about a year ago with Pagid black pads; a little dusty but certainly good quality. I always wire brush and clean the caliper carrier contact points when I change pads.


Now that I've been driving the vehicle for about a week after replacing the front drive shaft, it seems like the clunk and rattle are reduced by about 50%, but it's really hard to tell as the roads are clearing of snow and aren't quite as rough.

Any more parts changed or troubleshooting?

I keep seeing this thread pop up....



SOOO excited, I think "Oooh, gonna hear what it turned out to be".




and no luck.

Put the summer tires on yesterday, and checked pad play side to side. Basically the same. Swapped pads side to side anyway. Pretty sure it's not pad rattle.

All I can say is that it seems the rattle is about 3/4 of what it used to be since I replaced the front drive shaft. I'm worried that it is in the transfer case, as you can cause a rattle by moving the front drive shaft up and down at the transfer case. May try rigging up a go-pro and flashlight in there somehow and go for a drive, but probably won't get to this for a few weeks. Sorry @Ard, but you'll have to find something else to amuse yourself with while self-isolating :-)

@LightlyToasted, is your rattle like this?
https://www.youtube.com/watch?v=jW6r4r3WL0s
https://www.youtube.com/watch?v=vVEh2y_wIuA

I spent 6 months about a year ago just like you. I replaced EVERYTHING in the suspension except the springs :) In my case, my front lower thrust arms failed a few months into their life. I had just replaced them so I started convinced it wasn't them. I replaced half the suspension, was ready to push the truck of the cliff, but before I did brought it to BMW. They charged me $700 to tell me to replace the other half of the stuff I hadn't replaced and were useless (later they gave me 300 bucks store credit back at least).
Eventually i got new lower thrust arms and that resolved the issue.
https://xoutpost.com/bmw-sav-forums/...ion-noise.html

I know exactly how you feel. It's terrible and I'm sorry for you right now, but soon you will be over it and then you can replacing your timing cover gaskets, valve cover gaskets, oil thermostat oring, valve stem seals, coolant pipe and valley pan just in time for the thrust arms to fail again... :)

Wow... That is eerily close to mine... and it started a few months after replacing my thrust arms. Was it the bushing that failed or the ball joint? I'd think if it was the bushing I'd have the wobble in the steering wheel like the first time. Thanks for the input.

It was the bushing. I had no wobble in the steering wheel, everything felt fine, just this terrible noise :)

The core of the bushing was torn away and the noise was the bolt ratting on the metal sleeve through the bushing.

The TRW arms i got were just bad. Early int he 6 months the noise was just from the left. I didn't realize it at the time but after finally solving it I recall being on a road trip to southern CA and hit the brakes hard on the freeway when traffic came to a standstill and heard a clunk. This is when the thing tore but in my head I thought there's no way it was the thrust arm, it's brand new (and was installed correctly with car with weigh on wheels). About 3-4 months into the debug, i was constantly replacing parts and testing things (aggressive breaking) and somewhere in there the right side tore and then all of sudden i had the noise on both sides and thought I was going crazy :)

It was a terrible 6 months, my knees and fingers are still recovering, suspension work is hard on the body!

You want to know the best part?
I replaced my older thrust arms with the TRW arms preventatively, i had no issue, just had a few years on them so swapped them to avoid any issues... terrible decision...

I think TRWthrust arms were taken off fcpeuro

OMFG, that's it! That's the rattle! I'll check out the bushing this weekend. That would be especially disappointing as I've just recently replaced that part. If it turns out to be the culprit, there's a case of craft brew coming your way.



Oh, and I've already done all of the gaskets on the top of the engine, and the oil cooler thermostat gasket. And I just got through replacing the rod bearings on my E46 M3. BMWs are killing me...

Still there unfortunately:
https://www.fcpeuro.com/products/bmw...-31126773949-1

My reply from November hehhe

I actually just replaced a set of thrust arms after only 20k miles or so. The left side had some play. The 20”s and rough roads really take a beating on these bushings. With the lifetime warranty from fcp, it cost me about $50 for a new set. Shipping for the old parts was about $40 via ups.

I might go with power flex urethane next time.
https://www.google.com/search?q=pff5...&client=safari

https://syncrodesignworks.com/produc...nt-thrust-arms

@SF2000x5 was I that poor bastard you referred to? :)

Haha yessir. Hope this fixes the rattle for Lightlytoasted.

I had exact same rattle as on the videos. I commented on 1 of those videos and the guy replied that it was front trust arms. If it was you then THANK YOU very much. :thumbup:

I replaced my with Lemforder and rattle was gone !:thumbup: Before i even had wobble during harder braking.

Strange thing was that with pry bar i couldn't see/feel anny play or loosenes in ball joint nor bushing. After i removed right trust arm, i could feel small play in ball joint with hand. Bushing looked ok to me. Left trust arm looked all ok, but replaced anyway.

Funny how such a small play can create such a loud rattle noise. :dunno:

But i still have some very small wobble when hard braking from 100 mph. :confused:

Same issue on many cars. it is my suspicion that when the suspension is unladen (ie up on a lift, wheels hanging) that the thrust arms are loaded in a way that they just cannot be moved. SO it all seems OK.


My theory.....

Yup, that was me on YT.
I also couldn’t detect a thing with the suspension on place. I was dreaming of rigging up a dyno with hydraulics to simulate quick bumps in the road before I just went for it and swapped the thrust arms.

I was checking trust arms at inspection pit, so suspension was at ride height and laden.

Your theory could be right. I think unladen suspension components probably can't show it condition as when laden.
So better checking at pit or wheel alignment lift, i guess...

To arb : I also couldn't figure it out. Then you said on YT it was the thrust arms. So i told myself - f*ck it, lets replace them and will see :D

And it solved the problem :thumbup:

Based on the recent comments, I've ordered a pair of Lemforder thrust arms and will replace them later this week.


If the bushing is indeed failing, what is causing the knocking noise? Is the thrust arm hitting the chassis? One post suggested that the outer and inner metal parts of the bushing were contacting, but I would think that would require the rubber to be so bad as to be easily detectable. If it is the chassis, I wonder if I could jam some foam or something between the two to see if it muffles the noise.

In my opinion if bushing is so bad that the arm is hitting the chassis, then you could easily detect it just by looking at it.

Like i said in my previous post, i had no noticable play in bushing nor joint when checking with pry bar. I found out that 1 ball joint had VERY small play when i pulled it/press it with hand.

It was making the same rattle/knocking sound as on the YT video.

Any luck? I almost ordered some on the Memorial Day deal with Advanced Auto... hoping to get your feedback first.

I just finished replacing the thrust arms about an hour ago, but haven't gone for a test drive yet. Both bushings were fine, but the ball joint on the left arm had significant play. Since my knocking was from the left side, I'm hopeful that this was the cause of the noise.


Will take a test drive tomorrow morning and will report back.

Problem solved!!!:dance:


Clunk from tap braking, and rattle from stutter bumps is gone.


I checked my records, and I had replaced the tension struts / thrust arms less than 2 years and 14k km ago which is why I didn't suspect them. I can't believe the left ball joint wore out that fast. I can make it click by hand. The right ball joint, and both forward bushings were fine.



New tension struts are Lemforder from FCP, so if they fail again at least I'm covered for parts.


Time for a well-deserved pint. Wonder what's going to explode next....



:guinness:

My crystal ball says coil #3 is next hahah might as well do the valve cover gasket(s) also

Awesome! Now I can decide whether it is worth trying to replace the ball joint without any of the specialized tools....

Is the ball joint replaceable by itself? If so, any links to the part?


Replacing the whole control arm doesn't require any special tools.

I've also replaced both arms, and I get the knocking on both sides (maybe I installed wrong?).

I thought there was a post here or bimmerfest where someone replaced the bushings and ball joints... but I might be just thinking about the bushings. ard has a memory like a steel trap, so maybe he'll point us to it.

Might as well replace the arm for $80 since the bushing is usually fails first. Cost of the ball joint and bushing is probably close to $50 anyway.

Good point. It has probably been 50k since I replaced them... would be my luck to do just the ball joints then have the bushings go bad lol.

Have you checked the strut mount bushings? 8 and 10

https://www.realoem.com/bmw/enUS/sho...diagId=31_0795

I did replace them. I thought I might have a strut problem for a long time since I was able to compress the strut by hand enough to get the doughnut underneath in without disassembly. Haven't been able to confirm what force is required to compress the strut itself from anyone.

I replaced most front suspension components and still hear a slight knock going rolling low speed on slightly bumpy roads.

I think my struts are failing also but rather not spend $1400 on new front struts (EDC struts) on what I speculate is the problem. It doesn’t seem to bounce as if struts were blown but they’re likely original struts from 13 years ago.

How were you able to compress the strut? Were the parts off the car if you’re body weight helping you? This is the only way I imagine I’d be able to compress working struts.

When you take off the nut on the top side, then jack up until the wheel is off the ground, you will have an almost fully extended strut. I used a long allen and was able to compress it through the wheel well with body weight. It wasn't easy, but easier than I expected it to be.

I'm sure they need to be replaced... I just don't want to replace them and NOT fix the knocking. If new thrust arms don't do it, I'll probably bite the bullet on black friday.

New thrust arms fixed the problem. Brand that failed immediately was Vaico. Ride is back to smooth and quiet.

The ball joints were shot.

Awesome! In my case, failed brand was Mevotech Supreme. Replaced with Lemforder.