truck pulls left when braking

1993 GMC 217k miles 4.3 1500

i replaced my calipers and brakes already and it didnt fix my problem. when i brake, my trucks pulls to the left. the faster i am going, the harder it pulls.

the pull goes away after a whole second of braking and then its normal until i let go of the brake and then it pulls again when i brake.

i did bleed the air out the lines too. its the front that is pulling.

what could be bad?