YOU SAID:

I once farted so hard my pants ripped

INTO JAPANESE

パンツが破れるほど激しくオナラしたことある

BACK INTO ENGLISH

I've farted so hard that my pants broke

INTO JAPANESE

おならしすぎてズボンが破れた

BACK INTO ENGLISH

I farted too much and tore my pants

INTO JAPANESE

おならしすぎてパンツ破れた

BACK INTO ENGLISH

I farted too much and tore my pants