Hi I got my alternator replaced but now there is a rattle I have worked out the 2 metal pipes I think for the air con are off the bracket so the rattle could be from there. 

Does anyone know if the mechanic needed to move the pipes to change the alternator? 

 

 

 

 

 

 

 

 

Entirely possible, I'd say even probable. The alternator is beneath the Aircon compressor isn't it. Not a lot of room. Some removal and maneuvering I'd say required  photos of your specific model, engine and which air con pipes you are referring to would allow more comment. 

https://www.youtube.com/watch?v=lza04G53Evc

https://www.youtube.com/watch?v=EcS3qqJ_wCY