New brake discs are here, I'm having a little trouble undoing the 17mm bolts holding my 4 pot calipers on. Is there any suggestions on how to get these to slacken off??

Thanks Melon.

 

Loads of WD40 and leave for an hour

 

the car is jacked up as we speak and has a similar substance to WD40 on there at the mo, well in fact its a proper re-lease oil and its been on there a while but still no joy bohooo was hoping to have them on today.