Jack up the front and put on stands. Have a friend push on the brake and have him tell you as soon as he releases the brake to see if you can turn the front wheels.
If they both release immediately then check your rear brakes. An unadjusted right rear can cause a pull to the left.
Also there could be one other problem in the "rubber" brake line that goes to your front calipers. It doesn`t happen very often but the inside walls can deteriorate/collapse and hold pressure to the caliper. You will notice this if you can`t turn the front wheel as soon as your friend releases the brake pedal. Try to rule out everything you can because I`m sure you don`t want to be just replaceing parts.