Replaced Drive shaft now I have more problems

[27boyd]

So I had to replace my driveshaft and instead of buying a new one I had my dad and his friend (who repairs drive shafts) cut out the old U-joints and weld new ones in. Everything went back together just as it came out. That being said. I don;t think the drive shaft is my problem. After everything went back together we took it for a drive and the exhaust is leaking, I assume at the headers where we disconnected it AAAANNDD there is a stupid amount of vibration once I get up to speed. We also rotated the wheels because the front tires are a little worn on the inside. So my questions are. How do assess and fix my exhaust leak? And more importantly, what is causing the vibration? What should I check for? Thanks in advance guys

[dnguyen1963]

Pic of the weld? My guess is that things did not get welded perfectly.

[itsonlygeorge]

Driveshaft needs to be rebalanced.


Sent from th

[27boyd]

These are the welds.

[27boyd]

I thought the balancing might be off. I guess I'll be taking it back out then.

[DirtyTh3rty]

How was the CSB?

[TobyB]

Those aren't welds. Or rather, those are fusion welds...

Oh, wait, WTF- they tack- welded the bearing caps in.

That's a new one on me. Seems like it could distort the races that are the inside
surfaces of the caps...

Yeah, I'd say start with a driveshaft rebalance, and see if the balancing shop finds
any problems with the spider and cap replacement...

t

[bmwman91]

They need to balance the driveshaft is an assembled unit, not with the halves separated. Also, you need to bias the CSB forward 4-6mm (when you get everything assembled, move the CSB ~5mm toward the front of the car so that a little tension is in the rubber web and then tighten the 13mm bolts).