The leak off pipe on the BMW diesel is prone to breaking when moved or even just when driving, the plastic gets brittle
the upgrade kit from here
BMW leakoff kit on ebay
this is a HD brass kit but with one issue, the pipe they supply is rubbish and soon starts to leak after getting warm a few times, the solution is to use Gates 3.2mm pipe and some Mikalor spring clips like this..
This is the right way and last for whatever abuse you give it.