problem with 97 f150 brakes

my husband changed the brakes on our f150, which was fine until we couldnt bleed the brake calipers because both bleeding screws (one on each side) were stripped. so we changed the calipers. ok. so after changing the calipers and reputting them on, tried to bleed the brakes. could bleed them but we have no pedal.
went out and bought master cylinder, no luck, then changed the booster. still no pedal. does anyone have any suggestions on what could be wrong and how to fix ???

There is air in the system.

When he replaced the calipers, if the fluid got too low in the master cylinder, then you got air into the ABS system. You can bleed all the air out, but it is a real pain. I suggest that if you can, you CAREFULLY drive it to a reputable well equipped local repair shop and have them professionally belld the system, that will fix it right up.

Also, the bleeders go up. I know, but I have seen them installed upside down.

my husband changed the brakes on our f150, which was fine until we couldnt bleed the brake calipers because both bleeding screws (one on each side) were stripped. so we changed the calipers. ok. so after changing the calipers and reputting them on, tried to bleed the brakes. could bleed them but we have no pedal.
went out and bought master cylinder, no luck, then changed the booster. still no pedal. does anyone have any suggestions on what could be wrong and how to fix ???
thank you for letting me know the calipers can be put on wrong. they were on the wrong side, bleeder screw down. we changed them and now perfect brakes