So about 2 years ago I changed all the rotors and pads on my car. About 6 months later I felt some pulsation in the brake pedal and steering wheel when I would brake. So I used a runout tool to test the two front rotors. I discovered the passenger-side rotor was the culprit and changed it. I also noticed the piston was a little difficult to get back in the caliper. Now I feel the same pulsation. Do you think I should just change the caliper? My car has 90000 miles on it.