Driveshaft Removal
 

In the list of DIY articles is a good pictorial of removal of the W123 driveshaft & carrier bearing. There are some exceptions, however, that need to be mentoioned:

Even if it is possible to separate the DS halves on the car and remove the front half first (which isn't possible on all models of W123), the two halves should be removed together, and out the rear. Just loosen the clamping nut a couple of turns to allow collapsing of the two halves for flange/disc spacing.

And when installing the new carrier support w/bearing, it doesn't really matter which side faces front/rear. The bearing sits in the very center of the support. The rubber lip on the support is only for installing the bearing in the support. Once together as one unit, it can face either way.

Happy wrenching & motoring