Several things to consider here. First off, if this is a new to you truck, take a look at the slave cylinder. See if it still has the plastic restraining strap intact between the slave push rod and the clutch fork. If so, you're lucky. You can pull the fork towards the slave and use the restraining strap to hold the push rod in. This is a big plus because A) - you won't have to hurt your hand, and B) - you won't have to bleed the slave. If you don't have the restraining strap, you will have to dismount the slave cylinder from the bell housing, which is done easily with a big screw driver prying in just the right spots. You'll see how the clip that holds it on is designed, and how to get it off. Once the slave is off, or the push rod restrained, you can remove the boot and just yank the clutch fork out. Buy a new one from Ford, and throw that one away. Get a new pivot ball while your at it. These are wear items and yours probably should be replaced so that you can establish that you don't have worn parts. Now with the fork and ball out, you can easy put your hand in there. Take a rag with some solvent on it, and clean the shaft that the throw out bearing slides on. This is the tranny input sleeve, and if the TOB has been misbehaving, it may have groves cut in it, or metal shaved off. If this is the case, the input sleeve will need to be replaced. Once you get all the old grease off and it's clean, slather it up with new wheel bearing grease, and reassemble everything using new parts. Once you've done this, the clutch will push real easy. Of course you may have to bleed the slave, and look into the cracked firewall issue depending on your circumstances.
