Diagnosing rear vibration

[Jjcarr]

I'm trying to diagnose a rear end vibration in my 525it. At first I thought it was the driveshaft support bearing, but I replaced that, and there is no change. It's not the tires, as I've used two sets with the same result, plus it just doesn't feel like the tires, because I can feel it at low speed as well as high speed.

I've replaced the pitman arms, but haven't done the rear subframe bushings. There is also a noticable knock when comming to a halt, but I haven't been able to determine if it is comming from the front or rear.

I'm also curious if there is any way to diagnose a worn driveshaft?

James
95 525it

[Rigmaster]

If it's REALLY worn, there will be play in the u-joints. You can jack up the car or put it on a lift, and grab a section of the driveshaft by hand and turn it back and forth. Bad play in one or more u-joints will be obvious.



Bret.

[Brandon J]

How many miles are on the touring and what has been changed over the years?

As Bret said, it could be the u-joints. It could also be a lot of worn out or broken parts. Some other places to think about is the subframe bushings, axle bushings, the brake rotors, if the front wheels are not vibrating, then swap them to the back (I have seen 2 different sets of wheels unbalanced as they were both used for the same axle), CV joints, gunk in the inner brake drum assembly (parking brake), Guibo/flex disc, bad output shaft bearing on transmission, bad flange bearing on the differential, control arm bushings, sometimes bad rear strut mount, bad transmissions mounts, and perhaps a few more.

Now a few questions:
1) Is there any delay or clunk when you accelerate at low speeds or from stop?
2) Do you feel the vibration more from the seat or the cargo area?
3) Do you feel any vibration in the steering wheel?
4) Can you describe in more detail the noise, clunk, when it occurs, any other times, when you began noticing it, how loud, pattern, etc.?

Here is a link from doing a search for some ideas and a procedure to check your CV joints: http://www.bimmer.info/forum/showthread.php?p=3061#poststop

Good Luck.

[Jjcarr]

How many miles are on the touring and what has been changed over the years?


Now a few questions:
1) Is there any delay or clunk when you accelerate at low speeds or from stop?
2) Do you feel the vibration more from the seat or the cargo area?
3) Do you feel any vibration in the steering wheel?
4) Can you describe in more detail the noise, clunk, when it occurs, any other times, when you began noticing it, how loud, pattern, etc.?



1. Sometimes I hear the clunk when I accellerate from a stop, but very rarely. Normally it occurs right before the car comes to a complete stop.
2. The vibration feels like it's comming from the rear, but I haven't ridden in back to verify.
3. No vibration in the steering wheel.
4. Hard to describe it more, just a mild clunk just before the car stops.

I've replaced the pitman arms, and done the thrust arms. I've had the brake pads off and didn't see any sign of slop, but I haven't gotten into the emergency brake pads yet.