Trunk Lid Hinge Retrofit and Bear Claw Latch
1951 Ford trunk hinge assembly, sandblasted and painted. Got them from Roger in Geneseo, Kansas. I compressed and locked the springs to remove the pin holding the compressed end in place with a cut down tent ground stake. yup. Tied it down so it didn't accidentally come loose and cut off a finger or something...
Marked up area now cut out. There will be lots of loss of strength in this area, but I will be using "gas cylinder spring" rather than the '51 hinge springs, which puts all the torque onto the mounting area. With two gas cylinder springs, the hinges don't take any torque. By the way, Dremel has a cool little cutting wheel with a snap together chuck that works really fine for detailed cutting.
To get all the spacing and position correct, I got new trunk lid gaskets, put them temporarily in place, and shaped some chunks of clay on the trunk lid, then crawled into the trunk and pressed the hinge mounts into the clay. That put the hole positions in place to make a weld-in piece with welded nuts for the bolt mounting.
Preliminary template cut from a manila folder, then marked on 18 gauge paintgrip sheet, but with about a quarter inch more material for "mismeasurements".. then massaging the plate to fit. Note that the left side is flat against the trunk lid inner surface, and the right side is lifted about 3/8 to 1/2 inch because the new hinge mounting surfaces are parallel to each other, and the inner surface is sloped and parallel to the outside of the trunk lid.
It's important that the mounting faces are parallel to each other so the hinges don't bind. This straight edge shows I'm a little off, so final fitment will have to be adjusted. Decided later that it doesn't make a whole lot of difference if the hinge mounting surfaces are not perfectly parallel, as there is a reasonable amount of flexing in the hinges.
This a drawing of the "Basic" plate, 18 gauge, of what I used to make the hinge bracket mounting. You will have to massage these dimensions a little bit, but if you start with this, you can get things to work out. Corners need rounding where needed, some trimming here and there, but for the most part, this is a good start to build your hinge mounting plates.
After a trial fit of the location and elevation of the trunk lid mounting, cut the spot welds loose after marking location, and welded a pair of nuts to the back of the mounting plate. Not welded yet in this picture. That Dremel large cutting wheel is just GREAT ! (Marked trunk lid just to assure that the plate goes back in the same location.)
Bear Claw trunk lid latch. It has to be exactly correct in it's position, up/down, left/right, front/back. Not easy to finally get it perfectly located so that when the trunk lid is closed, the height and sideways position is maintained. Green wire is so that I can unlatch from the outside. Will be installing a solenoid release AND a manual release...just in case...Notice the thick body filler applied by some prior owner. Didn't know it was there, and when I screwed in the angle bracket for the latch, it went through and dislodged the body putty. Another repair .....
In order to assure that the trunk lid is reattached exactly in the same position (note the slotted bolt holes), I drilled through the hinge and the bracket, opened the hole up on the hinge so that it is a very tight fit on the screw shaft that is screwed into the bracket, then cut the head off. This way, when I put the trunk lid back on after finishing up the welds on the bracket and welding the old hinge holes up, the lid will be perfectly aligned when I put it back on.
Trunk lid gaps suddenly started spreading out... Looked closely at the '51 trunk lid hinge replacement parts. Never saw those stress cracks before installing. They both started to open up/bend.. So I made a sandwiched dual thickness 18 ga piece, and welded it into the inside groove of both of the hinges. Had to heat, bend, and trial fit the corrected curve hinge to assure correct positioning, Remove and weld in the support piece.... Not pretty, but you can't see the welds when installed...The '51 design was flawed, due to the fact that the spring loaded hinges (no support rod) hold the entire weight of the trunk lid when opened. Any binding and every time the trunk lid was closed for 68 years eventually caused the hinges to fail as stress cracked developed. I'm using the '49 support rod and removed the hinge springs, thus removing any more hinge stress.
