And after all that the rusted in bolt proved tougher than our removal attempts. The folks at my Subaru dealership even tried and broke it off again. So I’m buying 4 new feet with 4 new bolts (approximately $50) so we’ll have all new attachments to for the sky box to the car. I figure it’s a relatively small insurance policy for a box that is going to hold over $2000 worth of ski gear on a regular basis.
solved or no
getting torx and hex bits for a socket wrench are well worth it, even inexpensive ones are good for occasional use. you can apply much more force in a controlled manner. using a small wrench (the single right angled things) and trying to apply force often causes you to loose control and damage the head or nearby surfaces.
lube up and give it time. relube. use the socket with moderate force. escalate as needed.
also if roof parts are removable then remove them when not in use. the elements corrode things in place. if not removable then loosen and move the assembly every six months to keep it from freezing up.
It might be worth your while to get stainless steel equivalents of the screws you have, and use those.
Good to see you had success. I was going to second the opinions of those that recommended drilling the offending screw out. But I wanted to add that you can getleft-handed drill bits. When used on a rusted screw, they turn in the proper direction to remove the screw rather than tighten it further. Often the screw will begin to back out before you get in deep enough to damage the threads.
This. Cut a slot with a dremel cutting disk. Soak the screw with a rust remover, not just oil. Gently whack the heck out of it with screw driver and hammer to break it loose enough for the rust remover to penetrate. Work it back and forth because the rust will bind up in one direction. Once it moves a little add penetrating oil. If you have an impact wrench set it on low so you don’t snap it off and gently work it in and out. You want love taps on a small screw not 280 lbs of torque. It’s the constant tapping that will get the job done.