TOOLS NEEDED:

1. Something to remove old hinge: a modeling/jewelers' saw, new X-Acto, Dremel tool,
whatever you're comfortable with.

2. Sandpaper/fine tooth file

3. Superglue

NOTE ABOUT PAINTING:

If you want to paint the hinge to match the trailer, do *not* paint the inside of the hinge!
This is very important...if you do paint it, the glue will not stick to the part and it will fall off.

INSTALLATION INSTRUCTIONS:

Before
A broken trailer tab, typical for G1 Primes

Step 1
Remove the side of the trailer by sliding out the metal rod (nothing high-tech here, I just use 
a bent paper clip to push the rod out a little bit, then grab the exposed end and pull it out the rest of the way).

Step 2
Cut off whatever is left of the old hinge according to the arrows in the photo.  The cut should be as 
straight as possible, and only remove the outer edge of the plastic (do not cut into the channel, or 
you won't be able to reinstall the metal rod!)

Step 3
This is what your final cut should look like.

Step 4
The arrows in the photo indicate where the new tab should be glued into place.  I recommend a bead of 
superglue along the top edge, and two small beads on the bottom edge.

Step 5
This should be about what the part looks like installed.

Step 6
The new hinge should line up exactly with the old plastic; if the end result is not a smooth curve, sand 
the edge a little bit until you get a nice "O" shape.

End
Reinstall the side of the trailer, and your Prime is ready to go!

ADVANCED NOTE:
The original design of Prime's hinge is not very strong, which is why it breaks so easily.  Replacing the 
hinge as outlined above will make your Prime look like it did originally, but if you'd like to make your 
hinge even stronger I'd recommend the following steps.  It will permanently alter your Prime figure, and 
it will not look exactly like the original, but I have tested it myself and I think the results are well worth it.

Advanced Step 1
Before reinstalling the trailer side, cut about 5/8" - 3/4" off the end of the metal rod.  Put the trailer side 
into place and insert the rod as you would normally, using something (like the bent paperclip mentioned 
above) to seat the rod all the way.  This should leave the last section of the channel open.

Advanced Step 2
Take the remaining section of the metal rod, and cut another 1/8" - 1/4" from it.  you should now have a 
short section about 1/2" long.  Carefully insert this into the open end of the channel, and stop when the 
end of the rod is even with the end of the channel.  Be very careful with this next step: put a small dot of 
superglue on top of the end of the metal rod.  Capillary action should draw the glue around the rod, essentially 
filling the gap between the metal rod, the new hinge, and the old plastic.  If the drop of glue just sits there, 
coax it into the groove with a toothpick.

Advanced Step 3
Add another small drop of glue once the first one disappears...continue this for 4 drops, or until the glue stop disappearing into the groove, whichever comes first.

Give the glue a chance to fully set (usually a couple of hours), and you can reinstall the door and call it a day!