2008 xb rear disk brakes on xa
 

Has anyone tried to convert 2008 xb rear disks for xa?

I highly doubt that is possible. They are completely different chassis and suspension setups.

yup. so is the 1988 corolla gts and the conversion was done with a simple caliper mounting bracket being custom fabbed. difference with the 08 xb is that it still has the same torsion beam suspension as the xa. i haven't checked to see if 08 xb has 4 or 5 lug rotors, but if they are 4 lug i would assume that it might be easier to accomplish than with the 88 corolla approach. i believe that you need to shave off 1/5" from the inner diameter of the corolla rotor to fit on the hub. also be nice to use new toyota calipers rather than remanufactured ones from the 88 corolla. but at this point and with all the custom fab work needed to mount the calipers, might as well go with a set of brembo's or other calipers.....hmmm..... soon. since im not turboed yet, i have no need for the added braking yet....

they are 5x114