The 2cv4  driveshafts have 3 protective cups, which the rubber gaiters fasten to, in order to protect the double cardans [hardy spicers to you and me] from the elements etc. Special tools are needed to dismount them and re-mount them properly. On the hub end of the shaft is an interference fit collar and it is extremely tight. It has to be destoyed to dislodge it. I have searched for new replacement collars but cannot find any, so I made a batch of them. When the driveshaft is inserted into the hub, this collar is tightened up to the wheel bearing and the oil seal rides on its outer diameter. As soon as you try to dislodge it, it will be damaged, so it must be replaced. A video is available for these items.
Wheel bearing end of shaft Sliding joint end of shaft. Note the O ring. Gearbox end. Note-- no O ring, cup is a slide fit
collar and cup removed This is also a tight fit
Puller attached. The cup could buckle on the Knocking a cup into position The collar has a recess, this fits to the cup ring.
very tight collar
The collar after grinding a flat Carefully split the collar Old collar removed
Be careful not to damage the cup Don't damage the shaft surface
A new collar A batch of collars Tube drift to mount a cup
The tool kit consists of 3 pullers. One is a horseshoe shape and the others are split halves. On 2 of the cups is a raised lip and the 2 different sizes of pullers surround and clamp to the lip area with a circular ring to keep them in place and together. Pulling them off is easy and no damage occurs to the cups. It's the one with the collar that is the problem. If you heat the collar, you still won't be able to pull it off, as the heat transfer will prevent the loosening of the interference fit. It will have to be ground down. Fitting a new collar is easy. You will need to use heat resistant gloves. Heat the collar, away from the shaft, and place it on the shaft. Next mount the insertion tube and screw on the hub nut. Give it some more heat and position it, its recess will allow it to be positioned. Align the tool and screw down the hub nut until tight. Check that the cup is home by trying to rotate the cup. When installed on the vehicle and tightened up, it will be in the correct position. These tools are for hire only, or send your shafts to me for repair of the double cardans.