hi guys, need help. i havea toyota noah 96 model, having problem on both front disc brakes, it becomes sticky even at a shortdrive. I have replace the caliper kits 2 times with in a month. the first one , the o ring is the same with the old , after a few days, it gets sticky, then my mechanic replace it again, slightly smaller than the first. but still after a two days it gets sticky again. please advise guys.

thanks and more power