Flat head screw on radiator cap

I also found out the hard way you had to remove that screw before removing the cap cover. Not knowing any better, I forced the cover off
by bending the tab that the screw goes through. Of course, didn't know the tab was there until after I got the cover off. Went to Ace Hardware
picked up a replacement screw. Weird design Argh
I know better now.....
Larry
 
I bought my Rocket used (someone else bent it), so I didn't know why I couldn't unscrew the cap.
 
I don’t own a second GEN rocket, however, I have gotten stripped Phillips head screws out by gently tapping in a torque bit that’s just oversized, and wrenching it out. If the set screw and the material that it’s screwed into our two dissimilar metals, the threads may be galled up, in that case, you may have to drill the head out with proper size bit, then switch to smaller bit to drill the remaining thread shaft all the way out. This method should prevent damage to the cap if done correctly.