Strong vibration under seats while accellerating

[T. Martin]

I have a 1992 525i w/ 175,000 miles. I can feel a strong vibration under the seat/center console while accellerating. It used to be mild and became evident at about 10 to 15 mph and faded out before reaching 20 mph, the faster you accellerated the more pornounced. If you accellerate slowly you can prevent it all together. Now it sounds as if something is pounding under the car, however symptoms go away at about 15 mph. I was told it may be what's called a "carrier bearing" on most American cars and trucks.

Any suggestions are greatly apprciated... If have got a lot of good advice from this forum, but this is my first post.

Thanks,
Tony

[Travelfeet]

or possibly the guibo (flex disk) that's bad. Not too difficult to replace, but you'll need to get under your car. The parts are about $50.00 each from BMA. with high miles, the u-joint on your driveshaft may be going (which can cause the center bearing to fail) which is a bigger hassle. The u-joint may not be replaceable which requires a new driveshaft. Replace the flex disk while you are at it if it looks at all worn - cracks etc... A 525 with an auto may not have the flex disk. You'll need a high offset (inch or so) box wrench (14mm?) to acess the nuts on the rear of the driveshaft. Access is tight, too resessed for a regular wrench, and not enough for a socket. (at least this is how it was on my 540ia). The bently also recommends replacing the nuts on the front of the driveshaft (at the flex disk) they are one time locking. good luck

[JohnC]

yea does sound like the guibos going. my '92 525ia had it done twice already and i just hit 100K; i think im driving the car too hard.

[Messerschmitt]

Messerschmitt

[T. Martin]

I had the center bearing and the guibo changed, but now I have another problem. There is a strong vibration coming from the same area as before but now it is steady... it's the same whether accelerating or coasting. It never goes away, it simply fades away as you come to a stop. While looking under the car with it in drive and the driveshaft in view the half closest to the engine turns perfectly, however on the other side of the center bearing you can see the shaft wobble as it turns. My mechanic says it is my u-joints, however before replacing the center bearing and after replacing my thrust arms there was no vibration at all regardless of speed. (except 10-15 mph vibration caused by the center bearing) My question is how can my u-joint cause such a strong vibration after this repair, and not be noticable at all before the repair? My mechanic also states that my u-joint is not replacable, how can I find out for sure?

Thanks,
T. Martin

[Jr ///M5]

It's possible that your mechanic didn't index the driveshaft before pulling it apart to replace the center bearing.

The driveshaft should be indexed so it can be re-assembled exactly the same as it came apart. The shaft is balanced as a unit, and if it's out by 180 degrees, vibration will be the result.

I would find out first if he did in fact index the shaft, or look for the marks yourself. If not, you will have to pull the shaft apart and rotate 180 degrees, then re-assemble.

He's right about the u-joints not being serviceable, and worn joints usually require a replacement driveshaft to the tune of some $300. I hear frequent praise from people who have used Driveshafts of Portland.

You didn't mention if your car was an automatic or manual....only the manual transmissions have the flex disc or "Guibo" as some people call them.

[ryan roopnarine]

i'm not quite sure why people think this, or how this got circulated, but if the GUIBO you refer to is a rubber disc with metal grommets going through it for bolts, automatic cars can have them. Mine certainly does, as i changed it in February. I think that it is only e32s that have this distinction as a "firm" rule. Winfred also said that the guibo is common on auto tranny cars. Methinks i will be writing sean and Johan of the e32 page to suggest contrary information in their diagram. Stry enough, I was over at my friend's cousin's house, where he has a 98 jag xj8 on ramps....I saw a new part on the ground that looked stry familiar. Picked it up, and damned if it didn't look exactly like the one off of my car, complete with the Ger SKF box. he said the old one had shredded to threads and was causing the car to throw tranny codes.

It's possible that your mechanic didn't index the driveshaft before pulling it apart to replace the center bearing.

The driveshaft should be indexed so it can be re-assembled exactly the same as it came apart. The shaft is balanced as a unit, and if it's out by 180 degrees, vibration will be the result.

I would find out first if he did in fact index the shaft, or look for the marks yourself. If not, you will have to pull the shaft apart and rotate 180 degrees, then re-assemble.

He's right about the u-joints not being serviceable, and worn joints usually require a replacement driveshaft to the tune of some $300. I hear frequent praise from people who have used Driveshafts of Portland.

You didn't mention if your car was an automatic or manual....only the manual transmissions have the flex disc or "Guibo" as some people call them.

[Messerschmitt]

After replacing damn near everything including the entire driveshaft and all related parts the accelleration vibration seemed to be fixed. Now three months later it's back. I have no idea what it might be. I have a raspy vibration with any level of accelleration. It's worse at moderate throttle. Everything is new except the tranny. I'm starting to think that the problem is the torque converter. Anyone with me on this?

Messerschmitt

[Dick Schneiders]

My 1991 525i's certainly do.

It's possible that your mechanic didn't index the driveshaft before pulling it apart to replace the center bearing.

The driveshaft should be indexed so it can be re-assembled exactly the same as it came apart. The shaft is balanced as a unit, and if it's out by 180 degrees, vibration will be the result.

I would find out first if he did in fact index the shaft, or look for the marks yourself. If not, you will have to pull the shaft apart and rotate 180 degrees, then re-assemble.

He's right about the u-joints not being serviceable, and worn joints usually require a replacement driveshaft to the tune of some $300. I hear frequent praise from people who have used Driveshafts of Portland.

You didn't mention if your car was an automatic or manual....only the manual transmissions have the flex disc or "Guibo" as some people call them.

[632 Regal]

ATTENTION ADMIN....
Vibrations can be caused from virtually anything, from a worn trans/engine mount to a Guibo to a Center bearing To a improperly Phased driveshaft to Bad differential mounts....this post is the bulk of all the problems here and they are all seperate issues with no common fix.

I think this post should turn into a problem fix post that should be on the main page with the other fixes.