I have just taken out door #14 as I am stripping car #7, 2520R, a regency red Twin Cam.
The 1/2" bars on this pre-1973 car were hollow tubes, unlike the solid 1/2" bar on the TCS.
First you have to strip all the weight out of the door shell. The motor, the frames and the glass come out easily once you have stripped out the rubber channels and drilled the pop rivets. 2 in the top channel, 2 in the rear channel, 1 on the slanted part of the door on the inside, and several (usually 2 pairs) on the ally tabs which hold the frame to the flat top of the door. There are two small screws holding the triangular frame to the flat top. I used a small battery powered angle grinder to grind the tops off the impossible to undo nuts and bolts.
It took very little time to cut through the 1/2" tubes to get the 40mm gap in the bar.
I used 3 mole grips on the upper bar, wiggling it backwards and forwards 90', and spraying WD40 on top of the door where the washers are.
After wiggling the bar backwards and forwards 90' until it felt loose, I managed to get a 2 lbs hammer into the door, and bash the mole grips down while wiggling, until the top pin falls out.
If you cannot get the top pin out, you have to cut the tube with a battery reciprocating saw and either drill it out or drill a hole in the fibreglass above the tube and bash it down carefully, if you are having the shell resprayed.
Out of the 14 doors removed, only 1 bar came out the bottom as intended, the other 13 were rusted in place.
I am now getting good at stripping badly rusted cars. 20 days to completely strip a car to the bare shell for spraying, and completely repair, paint and rebuild the chassis including all brakes, brakepipes, discs, drums, all suspension bolts, and convert the rack and wipers to RHD.
I will soon have a line of resprayed shells, 3 black, 2 lagoon blue, 1 yellow, and 1 red, in various stages of rebuild.
I was lucky to find a 1 used wooden pallet right outside my office. 2 x 4ft 4 x 2 screwed to the underside, 4 castor wheels, and 2520R will soon be easy to push around.
I have 4 on pallets at the moment. The pallets measure 1200mm x 1000mm = 4ft x 3ft, so fit straight under the shell giving access to tanks and everything else once the chassis is off.