I decided to try to make one using the one in the passenger door hinge as a guide, without removing it. Just estimated the bends and it came out pretty good..I found an old coil spring and heated it red to uncoil enough, then made the bends heating it where needed. I installed it and with it clamped in a vice, it snapped open perfectly but when I tried putting it into the cab hole, the bends were too long and so I had to reheat and make some adjustments..it should hold the door open just fine.
