Brake get hot

I have a 95 plymouth neon 155,000 miles 1.9 engine does not have abs brakes. The front drivers side disc brake get very hot. So far I have replaced the the caliper twice and cleaned and greased all the bolts slides. I have bleed the brakes after I replace the calipers and everything seem okay. I have noticed that even the new caliper seem slow to let the brake retract when the peddle is released. What could cause this.