replacing a 91 318is u joint

[1988montecarloss]

so my 91 318is needs a u joint :rolleyes: anyway, ive read that theyre not replaceable but then i found some for sale that supposedly could be used with the original driveshaft if they were machined for it, if this is true what u joint should i be looking for? and what exactly has to be done to make it work? and will any machine shop or driveshaft shop be able to do this? thanks for your replies, your help is greatly appreciated

[DeepMidWicket]

drench it in inox and smack it with a hammer and they will normally come good

[DesktopDave]

We have a decent drive shaft place here in Pittsburgh - you might have one as well.  Those are the dudes to ask.
 
Are you sure it's the u-joint and not the CSB?