I never leave the truck hooked to the trailer while I'm working on it.
While doing brake work or just changing a flat while my rv trailer....bumper pull trailers....stock trailers....GN equipment trailers....cargo trailers sits on the concrete pad in front of my garage I use a hyd floor jack under the axle tube next to the U bolt on a std leaf suspension and lift just enough to remove the wheel. Nothing gets stressed...bent...crushed....twisted by doing so.
Out on the road or sitting in a campsite I use my trusty old 12T shorty hyd jack 1978 Trucker Special with a 10" X 10" base in place of the floor jack doing the same.
