Brake MOT Failure

Hi
My ML 163 270CDI has failed its MOT with rusty brake pipes
I want to replace them myself by getting some new pipe and making new lines
I have looked on ebay but i am unsure about a few things
The size of the pipe on an ML
Are the jointing pieces (the nut) the same industry wide
What would be the sensible choice of pipe to go for
Any advice re this would be appreciated
Thank You in Advance
Sam