dura ace hydraulic caliper with tight spot
 

my front hydraulic brake caliper has a sticky spot when applying causing front brake to grab. when I apply front brake at about 1/3 of application the lever hits a tight spot then breaks through the tight spot causing a quick application and brake to "grab"

my first thought is to clean and lube front caliper pistons and maybe give a good bottom hydraulic bleed.

the bike is equipped with a shaman dura ace lever and dura ace caliper and dura ace rotor r9120?

brake pads appear to be wearing evenly and bike does stop, more noticeable at slower speeds

Warped rotor?

today I removed the wheel and brake pads and carefully pulled brake lever to extend caliper pistons and cleaned them with shimano mineral oil and a qtip, then worked pistons in and out carefully with tire lever and applying brake lever. I depressed pistons cleaned everything with isopropyl alcohol and put it all back together. after a short test ride it appears to be fixed.