I let my RX-8 sit out in the winter weather too long (about a month) and now that I've jumped the battery it seems fine except the brakes vibrate more and more the stronger I apply them. What could be the issue?

 

warped rotors...looks like you need some new pads, rotors and maybe a brake flush, but i could be wrong.

 

keep driving it for the next couple weeks and avoid heavy braking they should come back.

sometimes when you let a car sit you get rust and other build up on the rotors that wears off after a few weeks of normal driving around. happens to me every yr

 

try hard braking several times without activating the ABS, maybe its just the rust

 

^+1

Get up to 60-70 and hit get on brakes really hard. Do this a couple of times to see if it helps.