This is all that holds the roof J bracket on, 2 screws that barely make it through the actual roof extrusion. But they use two per bracket, so that works
One of adjustment threads had gone rusty as well as a bit on the "j " so needed to remove for maintenance. Have added a stainless metal thread as a safety belt.
Be careful using S/S together wit Al if there ia any possibilty of water or moisture which will cause corrosion.
The direct contact of aluminum and stainless steel is not harmful and it does not cause corrosion unless there is some conductive medium such as electricity or water. So, the protection of connecting points between the stainless steel screws and aluminum ensures the prevention of corrosion. The removal of an electrical conductor by preventing the metals against the water makes the stainless steel and aluminum relatively inert. In the absence of water, direct contact between the aluminum sheets and stainless steel screws is not harmful. https://www.metalworkmasters.com/materials/stainless-steel-screws-in-aluminum/
Ken, the original screws are stainless, maybe 304 as they have a bit of magnetic attraction. There is no sign of corrosion on steel powder coated bracket, or on end of screw. But an interesting link. thanks
My rust on one thread due to poor coating of same, the other three are all still as good as new. But the whole thing looks pretty poor design/assembly when examined closely. Rivets , thread, weld? between thread and j bit, weld? on shiny D shape.
But no obvious stress anywhere, so what keep the roof down ?, mostly inside locking /lifting bars I think.