I really need some help. I have a 2011 Sonata with a 2.4 that is having strange issues where after a short time of driving the vehicle, the front brakes start to lock up and get hot. The strange thing it's not both at the same time. Sometimes it's passenger side, sometimes driver side. Well I thought maybe the master cylinder had an issue so I replaced it, no change. Then, took a look at each caliper and neither one is seized and moves freely. Next, I tried the small rubber brakes hoses thinking they may have been collapsed and not allowing the pressure to be relieved from the calipers , still no change. I can't quite put my finger on what is going in. Maybe something with the abs module or booster? I would think if it was a booster and had a leak or check valve problem, the brake assist would not be present and would be harder to actuate the brakes. Also usually if the abs module was faulty, I would think the brakes would lock when applying the brakes....I am at a loss to what's going on. I hate to keep throwing parts at it, and I consider myself a pretty good mechanic. Anybody with some wisdom they can share with me?