How do you ajust a clutch on a f250 pu?

You can adjust the clutch pedal by going under the vehicle and noting if you have a mechanical or a hydraulic linkage system. If you have an older truck most likely you will have a mechanical linkage. This is what i am going to explain here. With a mechanical linkage simply use a wrench to move the "bullet" into the clutch fork. There are two nuts involved. One nut moves the "bullet" and the other smaller nut locks the large bolt in place so it wont move through time. Sometimes the linkage has wear and it wont adjust easily. You will need to find to look at everything and make adjustment by either home fabrication, or if you can buy the part new. Not sure where you can get it though. I use fabricated my parts because no one appeard to have any for a 1981 Ford f250. Good Luck