Doors – Attaching a 2 x 4 to a door frame

1. The loose base is causing catching at the opposite corner because the entire door and frame is pivoting around the upper hinge and nearby framing that is presumably still attached firmly to the jack stud behind the frame. As the bottom left part of the frame swings out, the upper right of the door is moving up to where it hits against the frame there.

2. Take a look at the loose part of the frame and see if the nails attaching it to the jack stud have pulled loose. The hinge side of the door frame is often attached directly to the jack studs (no shims) so securing it may simply be a matter of driving in some brads or finish nails nearby.

   If there were shims behind the frame, they may not be where they were originally; then you'd probably have to remove the door trim to get some more installed in the gap, then drive nails through the door frame, shims and studs.

Reline your jamb with another material that you can screw into. The pressure you will subject the door frame to is really needing something screwed into it. To just use pressure has the strong possibility of deforming or worse, cracking your jamb, depends on where the shims are placed behind the jamb, but you cant see them, unless you take it apart, not a good idea, totally counterproductive.

There is more to sketch regarding the assembly how it fits together at the bottom. The idea is, it may be complicated to initially assemble/make, but that time spent now will pay off on how easy it is to assemble and take down.

I see it being 4 pieces, a plywood bottom with pulley mechanism attached, a hinged door head mounted to one of the side jamb liners with the pull up bar and tension bands attached and the ropes to link it all together.