Front end popping after axel end u-joint replacement.

Hey guys, Just did the axle end u-joints in a 96 XJ. (3" rustys lift, iron rock adj. track bar, 31x10.5x15 bfgs) Seemed to go alright. Got it all put back together, and took it for a test around the block. Made 4 left turns around the block at 20mph, seemed fine. Made a second lap, swerving from almost full lock left to full right and back. Went right fine, but going from far left back to center, heard a loud popping sound. Felt in floorboard too. Pulled it into the garage. I started it while parked, turned wheel full left and right many times, and no popping. I then put the front on jack stands, and turned them again. Silent. Rolled each wheel forward and back, no popping.

After this, I put it on the ground, got my roommate to lay on the driveway as I backed out and look to see if anything moves, that shouldn't be moving. Backed halfway down the driveway going under 5mph, got 1 loud popping sound. Stopped the Jeep, pulled forward 10 feet, put it in reverse again, get to same spot in the driveway, and it popped again. Back in the garage it went.

Roommate said he saw nothing binding or moving, but could not locate the source of the pop. I've check control arms, upper shock mounts, track bar bracket, sway bar links. Ive pulled and tugged on pretty much anything I can get my hand on under there, and it all seems tight.

Has anyone else had this problem, or did I forget something?

Thanks,

:smoker: C. Numb

Well you could pull the front shafts out again and move them around by hand and feel for binding. But if you feel confident that then install went well then you would need to start looking back through everything you touched. Check for loose bolts. Make sure the hub bearing units seated properly in the knuckle. I always put a wire wheel on a power drill and clean up the inside surface of the knuckle to get rid of dirt and rust. I even put a little anti-seize in there too sometimes if I have it lying around. That ensures that it goes back in and comes back out later without a problem. Check your ball joint nuts that that got tightened back down enough.

If all that checks out good, move to the track bar make sure the frame end mount bolts are snug and make sure the axle end bolt is tight and that the hole for it hasn't wallowed out.

Now if you have your Jeep is lifted with bigger tires and heavier wheels then this definitely could have happened, since you put a lot of pressure making those sharp turns in your testing, the factory steering box spacer could have snapped and be causing that sound. It is only made of Aluminum and they tend to crack, very common problem on these Jeeps. You can buy steel replacements from companies like JCR that will withstand the test of time and the pressures we put on these Jeeps. Shouldn't cost more than $30 for a upgraded steel steering box spacer.

"Axel", what the heck is an "Axel" anyway ?

Anyway...
You would not feel a wheel joint in the floorboards, because the suspension isolates it from the frame. My bet is a loose upper trackbar mount/bolt.

You need to ask someone to rock the wheel inside the jeep, sometimes takes a bit of a turn.
If that doesn't recreate the issue, I would try bouncing the Jeep up and down by hand.

When you can get it to pop, you can commence touching each steering/suspension component up front to narrow down where the pop is coming from.

Good Luck!
-Ron

Was all of this while you were in 2WD? The NP231 in 4WD on dry surfaces can make those noises.

The hub nut needs to tightened to 180flb. I have experienced a cracking popping sound from the axil spine turning slightly in the hub if the hub nut is not tight.