at wits end over noise...what else could it be

[bfowler]

i have had a rotational noise (pitch changes with speed) coming from the rear of the car. its not quite a "grinding noise" more like a rubbing noise, or smiler to if i had a bent rim" it get loudest at about 40mph, at freeway speeds i think the wind/road noise cancels it out a bit


so far i have:

-changed to my winter rims with brand new tires (checked balence and for bends when they were installed)

-replaced the rear wheel bearings

-replaced rear trailing arms and bushings (and front...not that the nose was coming from there anyway...but it was time for them to be done)

-had the car aligned

-replaced the guibo (and trasmission mounts, didnt think that had anything to do with the noise, but i was already up there replacing the guibo...)


-had transmission and diff fluids flushed and replaced.

none of this seemed to have changed the noise at all...in fact...the urethane bushings seemed to help radiate the noise.

both myself and mechanics are completely out of possible culprits for this noise. everything LOOKS fine.

anyone have any other ideas? it sounds BAD...unsafe to drive bad, but 2 different shops have both said everything looks good.

[Performance///M]

Maybe a stuck e-brake shoe?

[bfowler]

crap...that is something i over looked....and surprisingly simple!
putting that on my list of crap to check

[ekib]

Does it happen in gear at 40mph or in neutral at 40mph?

[bfowler]

both.

doesn't seem to matter: in gear, neutral, clutch in, accelerating or decelerating. noise just seems to vary with the speed I'm traveling.


and its not just at 40, 40 just seems to be the "loudest"

[OldCarGuy]

Maybe the brake disc is rubbing against the dust shield?

[EThirtySicks]

So the noise changes with speed, not engine RPMs?

[dswads34]

Check the driveshaft support bearing and differential... if you can safely lift the back of the car so that the wheels are off the ground, maybe try to reproduce the sound by putting the car in gear and locating the sound directly. If you're trying to do this at home though, you'll need a helper, and PLEASE be careful! Best of luck.

[vizsual]

This sounds almost exactly what i am going through. Same noise and on same pace of replacing everything imaginable.

[pac0]

Triple check for anything that looks like it's rubbing...something similar happened with a buddies Sentra brakes.

[bfowler]

So the noise changes with speed, not engine RPMs?

yes sir, that is correct

Check the driveshaft support bearing and differential... if you can safely lift the back of the car so that the wheels are off the ground, maybe try to reproduce the sound by putting the car in gear and locating the sound directly. If you're trying to do this at home though, you'll need a helper, and PLEASE be careful! Best of luck.

good idea...i will try and get it on a actual lift and try that. the bearing support "looked" good, but i will probably replace that too to say i did

[Spood]

Hey OP... any luck with this? Sounds like a problem I started having yesterday. I drove about 750-800 miles straight, and in the last 50 miles or so, it started making a sound like this from the rear end at highway speed. The difference with mine is that it started to fade, and then it would come back. Finally, once I was off the highway at lower speeds, it seemed like the noise moved "forward" to right around the transmission.

Your description of the sound seems similar. The other thing I would compare it to is a road surface noise...like if it was grooved or something.

[Hosephus]

Ditto, that sounds exactly like the problem I have been having. I know for a fact that the offending wheel is "slightly bent" according to my mechanic but he said it shouldn't be causing that kind of noise. If you figured it out please post what it was.

P.S. First time poster, long time lurker. Thanks to everyone on the board, your insights have been very helpful in maintaining my 95 325is. Kudos!

[Spood]

Ditto, that sounds exactly like the problem I have been having. I know for a fact that the offending wheel is "slightly bent" according to my mechanic but he said it shouldn't be causing that kind of noise. If you figured it out please post what it was.

P.S. First time poster, long time lurker. Thanks to everyone on the board, your insights have been very helpful in maintaining my 95 325is. Kudos!

Hey! A local!

Do you have vibration, or just noise?

[Hosephus]

Hey =)

Pretty much just noise, no steering wheel shimmy/vibration but the tone of the noise tends to make the cabin feel like it's vibrating if that makes sense. The car is completely driveable but carrying on a conversation at anything 40mph plus isn't the easiest thing in the world.

[HotDoggin]

Just because nobody has mentioned it, what about a driveshaft that's out of balance? (weights do fall off after all)... or something that's up with the diff... Could have a chinked tooth in the rear end or something with one of the bearings in the rear end...

Sounds like that's about the last thing that could be checked no?

[Hosephus]

At some point I am going to try and get a video of the noise, but that probably won't be til Thursday or maybe Friday depending on schedules.


Also, I replied to the above posters BUY MY WHEELS thread requesting a quote on the bottlecaps shipped. =)

Edit: Was just testing it out on my drive home. It is definitely emanating from the rear right wheel. When I turn the car to the right (lightening the load on the right wheels) the noise all but disappears and then reappears as soon as the weight of the car redistributes. No wheel shimmy at any speed and if there is any vibration caused by the problem it is minimal and isn't really felt in the ride so much as I notice when it hits certain pitches it creates some minor rattles in the cabin.

As I said, if a recording of the sound would help I can get that up later this week.

[Spood]

If loading up one side makes the noise louder, that's almost definitely a wheel bearing. I've had one go bad on this car, and two on my previous. They really can make conversation difficult. Anything from the drivetrain (as far as I know) should remain constant through turns.

[Hosephus]

That figures, that DIY looks like a bit much for me to tackle. Off to the shop when I get some spare cash...

[andycapps]

While you can just take the trailing arm off and take it to a shop to have them press everything in/out for you ;i just did it and i think $3-400 is a pretty good price for the job. Its not that bad to do, just time consuming. I wouldnt recommend trying this yourself if you havnt turned many wrenches before.

[Spood]

I won't touch this one even though I have turned some wrenches. There are a lot of things that like to seize in that area of the car...I'd rather pay to let someone else do it. That's just me though. What shop(s) do you use Hosephus?

[Hosephus]

I do a lot of the small stuff myself, but for the big stuff (thankfully very few items) I have taken my car to Autopia on hennepin ave in uptown. Yea, I pay more but I trust them and a friend of a friend works there. All I've really had to have done is my cooling system (shocker) about a year after I got the car and before I really got into the DIY section. I haven't had the 540 very long and so far she's been solid. (knock on wood.)

Can you recommend any good shops?

[Spood]

I'm a fan of Bona Brothers in Fridley/Columbia Heights (right on the border), and then there's a guy up in St. Cloud that I've taken her to a couple times...check this thread: http://forums.bimmerforums.com/forum...php?p=12877284. Bona Brothers has free loaners (when they're available), and fantastic customer service. Very professional and all that. Justin is also very knowledgeable and if it wasn't such a long drive, I would probably take her up there more often.

[Hosephus]

Bookmarked for future reference, eventually I'll have positive cash flow again and I can throw some money at the 325.