hello all, ive just bought year 2000 astra dti 1.7 van , it has a oil leak on the vac pump that sits on the alternator iv been told its the O ring inside it, is this a easy job just never worked on a vauxhall before, it looks like i could also do with a new or second hand alternator as the lights flicker a little, would it be just as easy to change the whole unit as it comes with the vac pump on it, and can you download and pdf files ion this engine

thanks
Andy