What kind of wrench do I need to take off the.

They are probably hex or allen key type bolts. Take a close look though. An allen key will not fit into a star bolt and star bolts are generally used for safety reasons such as seat belts or items that are easy to steal. You can go to a local auto parts store and get a specific brake bolt tool for your truck as GM uses a special size that is rather large and hard to find. Try Auto Zone roAdvance Auto.