3278

I bought my lifted Cherokee without a front drive shaft - I know, right? - so I bought a new one from Tom Woods recently. When I tried to install it, the holes in the front yoke are so badly filled with corrosion and mud that I actually broke a bolt off in the yoke. No big deal: we welded a nut to the busted-off stud and backed it out, but I need to use a tap to chase that yoke, so the holes are the right size and the bolts just screw right in.

So does anyone know what size bolt, and what thread pitch, the holes in the front differential yoke are? I've got a decent tap and die set, but I don't want to get the wrong size in there and end up needing different bolts. Thanks!

tmac

q

xj101

Drill them out and and run u-bolt style tie downs that slip through the yoke and are bolted from the back side . Waaaaay stronger then straps, Any auto parts store should have em !

Cheers good luck !

5-90

1/4"-28x1" screws will do.

Before you try to run a tap down there, take some SAE8 or SAE L9 screws, use a cutoff wheel to cut flutes in it (two should do, 180* apart and twice thread depth,) and use that to "chase" out the threads. You'll be less likely to cut new threads that way.

Tips:
- Lube the screw well.
- Back it out every few turns, or when you feel it getting stiff, to clean the flute out
- Go 1/2-turn forward, 1/4-turn back. This will break up any larger bits.
- Turn the screw by hand only! Pay attention, so you'll know if it gets stuck and you can back it out before it breaks.
- If you can't get it with the screw, you'll at least have gotten a positive start on the threads, and it will be easier to keep a tap in-thread (instead of cutting a mangled mess.) Use a "bottoming" tap (1-2 threads chamfered,) since you'll need rapid engagement to make sure you're "on the thread" before you start cutting anything (that's why you did the screw first. A little more work up front is better than a whole lot of work later, because you screwed up...)

Use new straps, but ditch those screws and go with quality (read: not made in China) socket head capscrews (hex is fine.) Advantages?
- These screws are heavily loaded in tension. The lesser section change from the shank to the head actually increases the tensile strength of the screw at that point, over what it would otherwise be.
- Socket head capscrews are routinely hardened & tempered to SAE8 Specs.
- The internal-wrenching head of the SHCS will be easier to work with around the caps of the Cardan joint.
- SHCS are easier to find - and cheaper to buy - than the OEM reduced/flanged hex head screws. You can keep those in your toolbox for "just in case" - but I buy a box of 100 1/4"-28x1" SHCS every few years, they last (I usually end up running out because I design them into something else.)

Notes on the screws:
- If they've been run, they get replaced. No exceptions. The straps can be re-anneled without too much trouble (thoroly degrease and clean, kitchen oven at max temperature - usually 500*F - for one hour. Then turn the oven off and let it cool min. 10 hours. I know it's not the "transformation temperature" of steel, but this DOES help.)
- When a screw goes into the yoke, it get LocTite #242 (or equivalent.) Don't bother with anything else, and don't skip the LocTite! Dropping a driveshaft while you're driving around town because you forgot to properly secure it bites big wind... Raise your hands if you've ever done this.

(raises hand, hangs head.)

You CAN drill it out for 1/4" U-bolts and nuts on the back, but it's a bit more involved (usually) than just drilling out the threads. Often, the backside of the yoke must also be spotfaced for there to be a flat surface for the nut to tighten against - if you don't have it, you'll never get torque set right! And, preload on the bearings will be WAY off... So, unless you're going to dismount the yoke, put it in a mill (or at least a decent drill press,) flip it over, spotface it, then install a new crush sleeve and put the yoke back in, I really wouldn't bother. easy enough to do the straps anyhow.

3278

1/4-28 is indeed the winner! Tom Woods called this morning to talk with me about them - how's that for customer service? - and hopefully I should be all set.

Out of curiosity, how hard would it be to pull that yoke off - remember, this is the front differential yoke - and either replace it, or tap/chase it on the bench, rather than under the Jeep? I can't remember what holds it in place, or if I have to monkey with anything else if I pull it off.

Looks like Crown makes - mine just uses reduced-head hex bolts - for a pretty reasonable price, with no worry I might screw up chasing the threads on the existing yoke. Thoughts?

3278

Oh yeah, duh. It'd be exactly as hard as changing the pinion seal.

3278

BTW, if anyone should turn this thread up in search later, the bolts you need are Spicer 231401, and the bolt-and-strap combo is the Spicer 2-70-18X. Thanks again to Tom Woods for the assist!