NCbob,
The problem is not the screws at this point, they mostly broke off as you mentioned. The question I have is, how do I remove the aluminum casting from the bus? I have removed or cut off the brass screws, but the lamp casting still will not come out with a lot of prying with screwdrivers.
Someone locally told me I might be able to use a sharpened 1” wide putty knife and slide it in between the back of the casting surface and the front stainless steel skin parallel to the front skin, then pound on the end of the putty knife to break the hardened sealant all around the 360 degree perimeter that was put in when the bus was built. He said once I break the sealant up, the casting should remove from the bus. I would like to confirm that this is the next step or is there something other than the 3 brass screws that hold the aluminum casting in the bus body.
Or if the old dried sealant is the problem, is there any solvent that will soften it up if I spray it daily for a few days so I can just pull out the casting?
Gary