Knocking sound from middle of car...

[be34st]

I went to check out a 535i/5 that im thinking about buying but like the title said it's making a funny noise.

It's a fairly loud knocking sound upon acceleration and goes away almost as soon as you exceed 5-10 miles an hour. I dont know much about the drivetrains on these cars but I;m thinking a bad guibo, or differential?

Other than that the car is cherry.

What could be making this noise?

[red_e30]

sounds to be carrier bearing on the drive shaft might not be the bearing itself but the rubber is ripped that holds it

[MR 325]

Yup, csb is the most likely cause. May need a guibo as well.

[KenC]

Probably needs a new driveshaft, CSB, and flex disk.

[be34st]

Is that a costly/difficult repair? Or is it something I can knock out with some jackstands, a few tools, and a few hours?

[DrLeadFoot]

CSB for sure. Replace the guibo while you're in there. Mark your drive shaft before you pull it apart. And check the u-joints.

Then drive

[John in VA]

If it is, indeed, the center support bearing rubber, you might consider replacing the guibo/flex disc and tranny mount "while you're in there." Stress on one area leads to stress on the others.
Check the universal joints on the driveshaft, as binding can cause problems. If they're bad consider a replacement from http://www.driveshafts.com/, or if you have a buddy at a repair shop go for http://www.beyerdriveline.com/mission.html

[be34st]

Thanks guys. I think i'm gonna go ahead and pick this one up. It's just too clean to pass up for the price.

[BavarianAddict06]

I went to check out a 535i/5 that im thinking about buying but like the title said it's making a funny noise.

It's a fairly loud knocking sound upon acceleration and goes away almost as soon as you exceed 5-10 miles an hour. I dont know much about the drivetrains on these cars but I;m thinking a bad guibo, or differential?

Other than that the car is cherry.

What could be making this noise?

Check the center support bearing. happened to my car. Its an easy fix :)

[BavarianAddict06]

Is that a costly/difficult repair? Or is it something I can knock out with some jackstands, a few tools, and a few hours?

Its 20 bucks or something. pelican or bma

[smooth]

There's a shop local to you that will rebuild it for $150 or maybe it was less it's been a couple years since I had mine done. You can spend $20 here and there fixing the guibo and CSB but make sure your ujoints aren't clunky because if they are you'll end up wasting money doing the rebuild anyway.

I replaced my guibo and CSB and then a year or two afterwards when I replaced my diff I noticed my ujoints were blown so I ended up having the whole driveshaft redone. I think the whole thing took three days max.

If you don't want to do the work yourself call Robert at e30motorwerks or Richard at Michaelangelos. Robert is further from you (HB) but more laid back. Richard is more of a drop the keys off and gtfo his way type of guy. He's over in Lake Forest.

[be34st]

Thanks guys.

I've ordered the CSB, so it should be here by the weekend. I usually take my cars to Pure Performance in Lake Forest. Daniel is a cool guy to work with. I haven't decided if this is something I want to tackle my self but I'm pretty mechanically inclined so it shouldn't be too much to handle.

[smooth]

It's routine but the u-joints are not serviceable so if they're bad you have to send it in or get a replacement driveshaft.

[be34st]

I hope that's not the case.

[xxx-Lost-Soul-xxx]

I hope you didnt get a Uroparts CSB. Pure CrapOLA.