Just spent a very unsatisfactory 3 hours trying to change the rubber diesel injector return pipes on my 2001 Veccy DTI. I had heard that these can give trouble, so when the car started to have problems starting due to the fuel draining back to the tank overnight, I realised this was the problem as air was getting in.
The trouble with these rubber pipes is that they are push fit onto the injector but are embedded slightly into the cylinder head. The heat from the head slowly hardens the rubber at the pipe ends and the pipes crack letting in air which causes the problems.
Trying to change them was a right pain as despite being very careful two broke off in the head leaving 1/2 inch of rubber in the head in a damned difficult place to get at. It took 2 hours to remove the remaining bits of pipe from inside the head .
Car has only done 60k from new. Lesson learned, mine will now be changed every 40k (every 2nd service) as I don't want to go through this again.