Just going up grade to Volvo XC90 callipers, I know I need 336mm discs but I’ve notice different thickness of disc does anyone know what thickness disc I need before order them
As above, get the discs and pads for the model that the caliper (and mounting bracket) have come from.
I have the 316mm discs (from a S-Max, but same as the Volvo's)...from memory the pads are the same for the 336mm setup, it's just that the mounting bracket is bigger to allow for the larger disc. I considered the 336mm setup but those discs are really heavy!
You can use use some online brake catalogues to check out the parts and sizes, eg: Mintex or Brembo give good information.
I replaced my discs with Slotted and pitted discs on both my previous Mondeo and my new one. They're the same size as the originals, but much better stopping power as the grooves and dimples eliminate brake fade.
I've also replaced the rubber hoses with braided ones.
My car stops on it's nose!