I replaced my mast assembly a year ago. Not much to it. I drilled out my rivots by putting pressure with a phillips screw driver on the back side and putting pressure while drilling. The rivots are soft. I replaced the rivots with machine screws and elastic lock nuts. You never know how long the fix will last. The mast assembly is GM part#22038195. I did mine without touching the outer fender. Did'nt want to mess up the paint on the bolt heads. Take off the inner fender and when you have removed the screws from the motor, remove the two screws from the antenna cable. Take off the coller on top of the fender. You can spin the motor 180 as you draw it towards the rear of the car. This allowed mine to come out. Good luck, that's the hard part. The hex tip on the mast unscrews to be used on the new mast.