Screwed up and it bit me.

[StealthTJ]

So, I'm out with two other friends, and on the last part of a snarly little trail (The Graveyard section of Miners Revenge, for those that may know the trail), and I'm getting up on this rock:



When Mike (who is off to the side getting a couple of photos) and I hear this "SNAP" !!
Mmmmm, rear axle...
Move forward a little.
Nope, both wheels still turning.
Get off the rock and get under the Jeep to take a look and I see what went "SNAP".

Now, rewind to a couple of days ago, to a slow moment at the shop.
I have a welded on "cradle" on the rear axle for the rear upper trangulated arms that has 5 holes for mounting the rod ends of the two arms.
I had them in the outer most holes.
For no better reason except that "it should be better ", I moved each of the two arms in one more hole (closer to the center of the diff), which is a far as they can go.
The arms had to be lengthened a little, so we backed the rod ends out something like 4+ turns and it fit perfectly.
A quick check of the pinion angle confirmed everthing was "good to go".

Now, riddle me this
What did I screw up on and what went "SNAP"
Dan, no fair answering



Fred

[cbassett]

Sounds like maybe those 4 backout turns on the rod end probably left you with a thread or two of engagement.

Or maybe you didn't finish welding on that cradle and moving in a hole changed the leverage such that you ripped the cradle off the housing.

[mrblaine]

Shouldn't it be -Screwed out and it bit me?

[StealthTJ]

Originally posted by mrblaine
Shouldn't it be -Screwed out and it bit me?

[StealthTJ]

Look at the jam nut in the first photo :0

Second photo shows the other arm and joint, still holding. You can see how much the rod end was screwed out here.

Third photo shows the cradle and five holes. The arms were originally in the outer ones.

Actually, seeing how little thread is/was engaged, I amazed that the Jeep made it as far as it did. The rod end pulled out just a few yards from the end of the trail, right before the waterfall.
This is a snotty little trail, and I'm very, very surprised that it held that long.
Had a heck of a time getting out. Tried rachet strapping the frame mount to the rod end and then easing up the fall.
Sort of worked.
Right at the top, literally, with the rear wheels just over the lip, the whole rear axle rotated upward, pointing the pinion almost straight up.
Couldn't remove the driveshaft like that, so we finally attached my winch cable to the winch point for this waterfall, and then winching forward, slowly, with the e-brake engaged (tranny in neutral) and that worked. It turned the axle back down.
Removed the rear driveshaft and then set the rachet strap up in a better position and was able (with some strapping and winching) to get off the trail and back to the trailhead.
Actually, looking at the Jeep today, up on the rack at the shop, it doesn't appear that anything is/was damaged too badly. Since the rod end was only slightly engaged in the arm, the arm appears usable still. I just chase the end of the threads.
I did destroy the rear u-joint (rear driveshaft) and straps, but thats no big deal to fix.
Also bent the shock mounts (axle end), when the axle rotated upwards. Simply fix though.
I think I got very, very lucky on this one and learned a hell've lesson in the process.


Fred

[DanB98TJ]

This is one of those "feces happens" things - I doubt I would have thought of the studs being that short, either. I'm just glad it waited until that point to come apart...trying to fix that in the loose, rocky (BIG rocks) section would have been damn near impossible.