I just got done with the home made Posi Lock because the vacuum unit went out, which I am sure a lot of you know how that goes. I tried finding a detailed (idiot proof) write so here is mine, for us idiots.
First the parts:
-NAPA 9ft Locking Cable, part 731-1104
-1/4" Compression Union
-5/8"x2-3/4" Compression Spring
-Piece of Metal 2"x3" roughly
-Rivets or Screws
-Various Box Wrenches
-Jacks and Jack Stand
-3/8" Drill Bit
-Various other drill bits
1. Jack the front passenger side up. Place on jack stand. Take off tire.
2. Loosen and remove 4 bolts on front axle fork cover (in red). Release weather pack (in blue). Pull off vacuum lines (in green). Place oil catch under working area.
3. Remove whole assembly, be careful with the gasket so you can reuse it with a little gasket sealer. See picture for whole assembly.
4. Drill a 3/8" hole one the left side of assembly. Hole size may vary with compression union.
5. Tap whole with 7/16" tap. Again tap may vary.
6. Drill a small whole in the fork, as small as you can get. Mock up whole assembly. Screw in compression union center, place in spring, place brass ball washer and nut on cable (don't tighten the nut onto the brass ball washer real tight until later). Place spring in and bend the cable wire slight. Test the locking cable by pulling the t-handle, make sure in shifts correctly.
7. Take it all apart now.
8. Find a place to mount the t-handle. I placed mine to the right of the steering wheel with diamond plate. You can mount it any where you want. Rivet or screw down plate. Screw down handle to plate. Thread the cable through the fire wall. I drilled a small whole through the main wire loom gasket.
9. Thread the cable around the back of the motor and zip tie down. I place mine on the heater hose because if I need a few more inches of slack its there. I have a ton of slack down near the axle so i doubt I will ever need this slack. I may move it to another location after some 4x4ing. You can mount anywhere you like. Route cable down to passenger side of axle.
10. Place the cable locking assembly back together. Tighten down the compression nut with the brass ball washer make sure the cable is in there nice and tight. Bend the cable wire and make sure it does not slip.
11. Place the cover back on insuring you have the fork lined up with the axle shaft collar. Put some gasket maker on the gasket. Tighten down bolts. Reconnect weather pack, vacuum lines to make it pretty. Place some gasket maker on the end of the compression union around the cable. Zip tie the cable to the axle make sure you have enough slack for articulation.
12. Check your work by chocking the wheels, turn the Jeep on, place in neutral, place t-case in 4wd, and engage the posi lock. The passenger hub should not turn. If it does check your slack in the cable or the shaft collar and fork.