Pinto Car Club of America

I was able to open the rear hatch once on my 79 wagon. But now the key just turns and nothing happens. I'm assuming something came apart, maybe a clip came off. The question is how to I access the lock? I'm tempted to take a hole saw and drill a hole behind it to see whaqt's going on.

The only way to access the lock assembly on the wagons is to open the hatch.  I have removed a hatch in the past without destroying the lock or hatch but I did not put it back together therefore I am not sure what other issues you will have ::)  I first unbolted the hinges from the hatch.  In your case you probably want to mark them before you unbolt them.  Be careful as they are under a lot of pressure.  The ones on my car opened once release but did not damage anything.  You may want to remove the plastic hinge cover and tie the hinges down to keep them from opening before you unbolt them.  Once loose from the hinges, I was able to raise the door up enough to unbolt the latch from the body using a wrench.  Once off I think you would be able to release the latch from the lock and eventually be able to remove the cylinder from the hatch.  Again, I did not put it back together so take this for what it is worth.  Good luck!

You can also slip an open-ended box wrench under the rear of the tailgate and unbolt the two bolts that hold the latch hoop (obviously, you're working from the outside). You'll need another flat wrench or small pry bar to lift the hatch as you do this. Once the lock latch loop is loose, you can open the hatch. From there, it's a simple matter of removing the lock and mechanism through the hole in the bottom of the gate.

"Open-ended box wrench"   sounds like an oxymoron to me.   How about a "combination" wrench?  Sorry Joel couldn't resist!

It's not going to happen. I tried to loosen the bolts but they are so rusted they just rounded off. If I have noting better to do I think I'll try drilling  a large hole in the interior side to see if I can access it. Otherwise I'll leave it for the next owner.
Thanks for the input anyways.