Upper door hinge springs

Looks like it is reproduced, check the usual vendors - APD, Galvins, Kennedy, Amark.  

The hinge pin, bushings, detent arm, and the detent arm bearing/pins etc. get enough slop in them until the spring gets enough clearance to slip out.  Check how much the hinge pins/bushings are worn by lifting up on the rear of the door.  You probably have worn pins/bushings in the door hinges.  I have rebuilt them before and it is not overly difficult unless one of the pins is broken off in the hinge.  The typical AMC vendors have a rebuilding service and I have seen some folks on this forum that rebuild them (AMX/Javelin anyway).  I think once you buy all the replacement parts, it is not that much more to have it done. - Good luck

Hope I didn't steer you wrong here, but the springs will come out again if you don't rebuild the hinge.  Parts per side (going from memory so there may be more): Upper/Lower Bushings (4 Total), Upper/Lower Pins, Detent Plate, Detent-Stud, Detent-Roller (like I said, by the time you buy all the parts it is not that much to have them done - but I usually do everything I can whether it makes sense on not .   I have rebuilt similar hinges on a Camaro with them still on the car.  The only AMC I have rebuilt is 68 AMX hinges with them off the car.  Some parts may have to be drilled out so they may have to come off the car.  Best I recall, after all the parts were replaced I used a large pair of vice grips to compress the spring and a screwdriver to pry it into position.  Took a couple of tries as I recall.  As usual the second side went a little easier.  My experience has been that the Driver's side needs everything, but the Passenger's side may be ok or just need some of the parts but if the spring is missing, it will probably need everything also.  Hope this helps

InRogue wrote: How do they even show up missing. Are they something that just shoots out there randomly?

The GM spring compressor I bought was useless with the doors in place.  I've been able to do it without removing the doors or hinges by compressing the spring with a drill press and using zip ties to keep it compressed, then cutting the ties once the spring is in place.  Sometimes takes more than a few tries but I've done four doors this way now.

Edited by CamJam - Jan/15/2021 at 8:05pm