Onmy '78 280Z, the door lock tumblers are fine, but the arm connecting the barrel to the locking thing seems to have worn out the hole in the arm where it attaches to the lock barrel. To unlock the door, you need to turn the key, then wiggle it up & down a some to get the lock knob to come up. Sound familiar? I've looked at it when I got the car, and the door panel was off, and it (the lock machanism layout) does't look a lot like the parts diagram, so I think the lock might be a later style ('79?) unit. the car is supposed to be an 11/78 build.

My idea is to make a new arm of steel or whatever to replace the one with the worn-out hole(s). Can anyone tell me if the lock mechanism is made of steel or aluminum? If aluminum, it would explain the wear & looseness.

Getting in there would be fun too.

Try Adjusting the lock arm at the striker mech...

Sounds like you need a new door lock AND cam assembly - go to a decent locksmith , and get a lock , set it to your existing key , then see if you can locate a cam from the dealer . Option 2 - find a wreck and get the part if it's in good shape . The plug's end drives the cam , and that's where the wear takes place . While you're in there lube all moving parts and mechanisms , including the window tracks ( guides ) . PS just replacing either cam or lock , not both , will guarantee future problems - replace both at the same time , with NEW parts if at all possible ! Also straighten any bent rods screwed up by over zealous tow truck drivers that like to slim jim cars open with force.