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Home made POSI LOCK write up

399K views 460 replies 167 participants last post by  DirectMatrix 
#1 · (Edited)
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
-Zip Ties
-Piece of Metal 2"x3" roughly
-Rivets or Screws
-Gasket Maker


Tools
-Socket Wrench
-Various Sockets
-Various Box Wrenches
-Jacks and Jack Stand
-Drill
-3/8" Drill Bit
-7/16" Tap
-Various other drill bits
-Rivet Gun

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.
 
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#3 ·
If I didn't already have a Posi-Lock I'd definitely try this.

Hey Mods...

I think he deserves a membership for the write up!

:tea:
 
#4 ·
AuroraJeep,

Thanks for the write up!!!!

I'm all over this. I'm doing a rebuilt at the moment and have been contemplating something like this in the back of my head since the start of my project. Especially since my vacuum hoses didn't come of "clean" when I was working on the front end.

Did you get your compression union and spring from Lowes/Home Depot?
 
#12 ·
The POSI-LOK's are fairly rugged in construction and should hold up no problem. This particular DIY setup appears to be a very good one also. Needless to say the weak link(s) in a DIY set up will always be how you attach it to the fork and how robust is the cable itself. Using a brake cable for a bicycle would be asking for trouble, IMHO, as an example.
 
#13 ·
The way I see it, is that it took seriously like 1 minute to pull that whole assembly out, if the cable slips off the fork it's an easy trail fix. Still half the cost of a new vacuum unit that is also prone to breakage. I plan on running a d44 soon, so this was a cheap, easy, and easily serviceable mod that fixed a problem. This NAPA cable wire was real thick, I am confident in it.
 
#18 ·
Will the 4wd indicator light in the dash still work with this DIY modification? Yeah, timatoe it's like the choke cable clamp on my 1953 Ford pickup. A small barrell with a hole for the wire to go thru and a set screw to tighten down on the wire. Outstanding write up,AuroraJeep. :cheers2:
 
#30 ·
X2 - I've had my cable stop pop off the end several times . I ended up doing the same thing and drilling another hole in the fork and feeding it back through . so far it has not pulled out. Just a note ... the first time I set mine up I just " balled up the cable " and it did not last long. It straightened the cable and pulled out.

Great write up ! I never seem to stop and take pictures when I'm working on the Jeep
:cheers:
 
#26 ·
Thanks

I was just fixing to buy one and poor folks need all the help they can get THANKS:cheers2:
 
#28 ·
I noticed in the "regretted Mods" thread that a few people regretted either buying a posi-lock or making one.

I wonder why? It seems like a good solution to me. Especially if you aren't off the road every weekend.

Any thoughts here before I spend the $50 to do it?
I wondered the same thing. I wouldn't change back. But I will be getting rid of mine if I ever get around to pulling the shafts out of the XJ D30 I've got sitting on the garage floor.
 
#31 ·
couple questions. You have the size on your spring. does it matter how strong or weak it is? And what did you use the hose clamps for?
 
#32 ·
When I did mine, I got the spring NAPA, and it turned out to be too weak and would not disengage the fork. I had to go to Fastenal to get a stiffer spring. It made the cable a little harder to pull but it works every time now.
 
#34 ·
Curious if there is a way to do this mod without the "tapping" of the housing. Some of us do not have access to a Tap and Die set.

Just wondering.
 
#41 ·
Curious if there is a way to do this mod without the "tapping" of the housing. Some of us do not have access to a Tap and Die set.

Just wondering.
I never tapped the housing. Instead I drilled a very close tolerance hole to insert the cable sleeve into (PITA), and sealed both the inside and out side with silicone. Its not going anywhere and nothings coming in or leaking out.
 
#37 ·
The spring was just a normal spring I bought at menards, the size is in the original post. The hose clamp I didn't use. As far as the tapping goes, this was my first time tapping something, I bought a cheap set from Harbor Freight for like $15. Mine doesn't leak at all and was just wheeling at the cliffs this past weekend. I used a little bit of gasket sealer on the outside where the compression union is and pipe tape on the threads, the outer cable doesn't move so it's sealed.
 
#38 ·
if that was your first time testing it,just in my experience.... if water does get into it the pin will rust over n you will not have 4x4 engagement. after going to the cliffs it took like 2 weeks till i noticed it. we need to hit up the cliffs together :cheers2: after i put my hd tie rods on of course. i missed the last run to the cliffs w u guys =-/
 
#39 ·
Totally, I am down to go again. I need to figure out what's the deal with my 4wd. The axle is lock up and the shifter is in 4wd H and the front tires don't move, found that out about two hours at the cliffs. If you have any experience or expertise to lend teejmcd come on over man.
 
#42 ·
Perfect timing for me to see this thread. Finishing up the motor swap/ major overhaul and now its time to get the 4wd going before snow.

Excellent write up, the previous ones I never understood to the point that I felt confident enough to start this project.
 
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