Hi, I have a 2014 fabia mk 2 , a mate removed the air pipe leading to the air filter housing ( to access a screw on the housing) now we can't reattach the pipe as the fit is too tight , tried lubricant and still won't slide on ,any ideas thanks

post image of what you mean ?

 

 

Try dunking in cup of boiling water ( be careful ) till soft then quick spray of wd40 and push on before it gets cold  and hard.