How do I get the rotor off to check and repack the bearings. I need to do this because the truck a little over 200,000 miles and I don't know how good a shape their in. Second things I broke a stud off of in the passenger rotor. How do I get in their to remove the stud. Next thing, the gas gauge doesn't quite exactly work. I have not replaced the sensor in the tank but I have been told it could be as simple as a bad ground. Where is this ground at.

Truck specs.

1989 F-150
4wd w/manual hubs
300 6 cylinder

Some of them have allen head bolts you have to remove and remove the assembly. They have lock nuts and nuts holding in the bearings.
I would suggest a Haynes manual with pictures you can look at. They also sell a bearing buddy so you can greese them without taking them apart completely. A library also has some manuals.
Auto Zone or Advance will loan or rent some tools.
Look for the ground on the frame back by the gas tank.