89 f150, 4x4, 300, T-18
The pedal mount brakket is broken and I will be replacing this as soon as the port comes in and the weather is decent (SE PA) How much trouble am I in for with this?

This problem seems to be independent of the bracket. The bracket has been cracking for a long time.
When the truck is cold, the clutch works fine, but the more I drive the worse it works. Pushing it to the floor won't disengage it. On a summer day after 30 mins in traffic, starting from a stop requires raking back through the gears with the clutch down to even get it into a low gear.
Mechanic said pressure plate, but mechanic wants me to get rid of the truck.
Grandfather said clutch adjustment, which was a problem after the master cylinder broke.

 

It could be the bracket. It's a hydraulic clutch, so there is no adjustment. If the broken bracket isn't allowing the clutch to completely disengage, then there's your problem.