Rear suspension mayhem

Had a little problem on a desert trip this past weekend. It seems I sheared off the leaf spring axle locater pins on both sides. The packs are from Rubicon Express and have far less than 2,000 miles on them. My shims got spit out which left the u-bolts loose and the axle shifted forward and started rubbing on the wheel well. The springs packs got messed up as well with no locater pin to keep the leafs in place. We used some straps to get back to camp and then jockeyed the axle back into approximately the right place. We then cranked down the u-bolts as tight as we could and put the straps back on for safety. We made the 200 mile ride home (towing a pop-up trailer no less) with no problems.

Has anyone ever had this happen to them before? It's a bit chicken and the egg in my mind... did the u-bolts get loose (I had just tightened them the week before) first (allowing to axle to bang on the pins) or did the pins shear first? I can't imagine those pins shearing off if everything was tight, no matter how rough the terrain.

Another weird thing... I had shims installed from Rubicon due to the height of my lift (6") even though I have a CV driveshaft and SYE. The axle is now sitting directly on the leaf springs but the pinion is still precisely pointed up at the transfer case. The perches appear to be fine so I'm a bit puzzled.

Fun times (not)!

i would bet the ubolts came loose, causing play and the broken pins, i dont think the pins normally break, once the ubolts pinch the leaf pack.

as far as the sye, did you get the kit before the sye? iirc, your supposed to be pointed down a couple degrees without the sye, but it should point right at the t/c with the sye installed...


hey, at least nobody got hurt! and you drove home! sounds like an interesting day, i dont think i'd call it MAYHEM.

possible you hit something hard enough to shear, but doesnt seem right for both sides. whered they shear at? ive pulled center pins out that look like a staircase so its not terrible uncommon, just for both sides. couldve had something to do with the shims

I haven't pulled the springs yet to look but since the axle was able to move and some of the leafs moved I'd say they're broken in multiple places or fell out. The u-bolts getting loose seems most likely but I just tightened them last week when checking the rig over before this trip.

The shims came at the same time as the kit and SYE. Who knows with Rubicon though... they also sent me a transfer case lowering kit even though I built the whole deal with them custom. What surprises me is that without the shims the pinion angle looks fine. I'd expect it to be horizontal to the ground without them.

Anyone ever had the pins replaced in a leaf pack?

did you 'just tighten them' because theyve been coming loose?

replacing the pins (assuming theres no other problems) isnt hard, you could probably do hardware store bolts, but they'll need to have the head ground down....

...or you could order new ones directly from rubicon express, depending on which way you wanna play it.

weird question, but is this a new lift kit? ie, purchased recently? maybe they got some defective bolts... breaking both on the same trip is weird...

should be able to find them at about any auto parts store. just check if theyre 5/16 or 3/8. loosen the leafs, stick a screwdriver threw the centerpin hole and clamp, then put the bolt in. super easy to do.

I've found the nuts to be slightly loose a few times. They were slightly loose when I checked them last week. I should have swapped them out for nylocks a long time ago (and will now). The lift has been on for years (but only a 1,000-2,000 miles).

It sounds like the pins will be easy so that's good news. Any thoughts on the pinion lining up fine even though the shims are gone?

1911Shooter said:

I've found the nuts to be slightly loose a few times. They were slightly loose when I checked them last week. I should have swapped them out for nylocks a long time ago (and will now). The lift has been on for years (but only a 1,000-2,000 miles).

It sounds like the pins will be easy so that's good news. Any thoughts on the pinion lining up fine even though the shims are gone?

Click to expand...

what rear axle? did you spin the axle tubes? check the welds where the axle tubes go into the diff housing.

Did you pull the pins and use them to bolt the shims onto the leaf packs? You should have, or made sure that the heads on the pins stuck through the shims enough to seat into the perches properly - at least 1/4" (or the thickness of the perches, if they are thinner than 1/4".) If you don't do this, it can cause problems. Since you didn't know how to put new pins into the leaf packs I would bet that the shims were not bolted to the leaf packs, leaving the pins not seating properly in the perches, which resulted in the axle sliding, spitting the shims out, and then breaking the pins. At least it was a fairly cheap lesson... you can make new pins out of grade 8 bolts or buy them from any truck spring/suspension shop, or rubicon express, and putting it together again won't be too hard.

Glad you found a way to drive it home! That really could have sucked.

I don't think I spun the axle tubes. I won't know until I pull the axle but I think it's unlikely in this situation.

I can't answer any questions about the shims and pins with 100% certainty. I was super busy when I bought this lift and after having it sit in my garage for six months I had a shop next to my office put it on. They did a lousy job and I've been fixing their mistakes ever since. Rubicon also sent some wrong parts with made things even worse. I'd always assumed (bad idea) that Rubicon supplied the proper length pins with the lift kit bit it's very possible they did not.

New U bolts stretch, especially for the first few weeks or runs and need to be retightened several times.

Something like that happened to me recently. The aluminum tapered shim broke and fell out which left the u-bolts loose, which sheared the leaf pack bolts. Steel shims and new u-bolts should prevent that from happening again.