tdci turbo issues

[lms1703]

I hope someone can help. Around two weeks ago the intercoller pipe failed. On the way to the dealer I had to drive the car hard to get any movment. I fitted a new pipe but I still have no real power. I have checked all the pipes and I can't find any issues. I did notice that there was no longer any suction coming from the vacuum diaphragm unit fitted to the turbo. I unbolted the vacuum diaphragm unit and tied the unit forward. I tested the car and the car was back to its old self with loads of power. I changed this unit on the hope that this was the fault but no the fault is still there. Can anyone give some idea. Cheers.