Loud pop/clang during articulation - XJ

98xj, 6.5" long arm, shackle drop, extended shackles, d30/d44, auto lockers front/rear, 35" km2, wj knuckle swap, OTK 1 tonne crossover (TRE), OTA trackbar (heim), RC discos mounted to teraflex swaybar relocation mounts.

I've had this problem for years. Started long before the WJ knuckle swap.
When i'm out wheelin and my flex moves from one side to the other, I often get a very loud pop/clang sound out the front passenger side. I'm never able to reproduce it while someone watches. Sounds like something get's loaded up and releases. Occasionally, I'll flex out one way, then go back flat, get no pop, then hammer on the brakes and it'll pop.

The problem I believe started even before the Long arm and knuckle swap and I believe I was only at 4.5" lift on RE. I thought for years that it was just a lobed out track bar mount, but then I fixed the mounts and problem didn't go away, and now I'm 4 or 5 track bars later (many upgrades), the WJ knuckles, 1 tonne OTK steering, 1.5"/heim OTA track bar, etc, and the problem still persists. Then I thought it was the coil loading up and releasing and smacking into the track bar mount, but I've fixed that as well and still have the problem.

Happens most often on the trail when I've got my wheels turned slightly. Figured maybe it was u-joints, so I swapped them out, and even threw in some new chromoly shafts (busted a stocker). The only thing left under the front that hasn't been replaced is the d30.

I did have some lobed out lower CA axle mounts, but I put some weld washers in and I don't believe they're moving now either.

All joints and mounts have been checked and re-checked.

Any idea's?

I had it on my old white rig. It was the unibody flexing due to busted spot welds. I eventually came back off the trail and there was a large gap at the front bottom of the front passenger door. I ended up doing a complete body swap.

That's not encouraging Thanks.

There's gotta be a way to find this though. And if it was a busted weld, would it really continue to pop like this for years of wheeling?
Where exactly did yours pop, and which welds broke?

Not the coil loading/unloading, maybe hitting something. Mine have made a sound like that before.

Sorry to be so negative. A common problem with popping noises has to do with the control arms. The bolts run through basically sheet metal brackets where they attach to the body and axle. The holes get egged out and no matter how tight you cinch down the bolts, from time to time they slip to a new position in the hole, making a loud pop. Somebody used to sell a large washer with a tight hole size that you could put on the bolts and then spot weld. Having a machine shop, on my first rig, I bought grade 8 fender bolts a size small and reamed out the hole for a TIGHT fit on the bolt and welded them in place.

old_man said:

Sorry to be so negative. A common problem with popping noises has to do with the control arms. The bolts run through basically sheet metal brackets where they attach to the body and axle. The holes get egged out and no matter how tight you cinch down the bolts, from time to time they slip to a new position in the hole, making a loud pop. Somebody used to sell a large washer with a tight hole size that you could put on the bolts and then spot weld. Having a machine shop, on my first rig, I bought grade 8 fender bolts a size small and reamed out the hole for a TIGHT fit on the bolt and welded them in place.

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Yea, already did the weld washers for the CA mounts years ago. Didn't solve it .
I'm goona try tying my sway-bar up higher next time I'm out. I know my coils do hit them when wheeling, but I really doubt it's the source of the pop, but I'd sure feel stupid if I didn't check

Tighten your bumper bolts and cross member bolts.

I have been known to spray paint over all the bolts and then go wheel. When you get back you can see if the bolt heads have moved.

old_man said:

Tighten your bumper bolts and cross member bolts.

I have been known to spray paint over all the bolts and then go wheel. When you get back you can see if the bolt heads have moved.

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That's probably more reliable than my "where isn't there mud" method.

Heims will pop if they're binding or on there way out

old_man said:

Sorry to be so negative. A common problem with popping noises has to do with the control arms. The bolts run through basically sheet metal brackets where they attach to the body and axle. The holes get egged out and no matter how tight you cinch down the bolts, from time to time they slip to a new position in the hole, making a loud pop. Somebody used to sell a large washer with a tight hole size that you could put on the bolts and then spot weld. Having a machine shop, on my first rig, I bought grade 8 fender bolts a size small and reamed out the hole for a TIGHT fit on the bolt and welded them in place.

Click to expand...

It will make no difference whether or not you weld a washer on the outside.

That's not how control arm bolts work.

They are there to clamp the ca mount to the bushing sleeve. That relies on the inside surface, nothing on the outside matters

blistovmhz said:

That's probably more reliable than my "where isn't there mud" method.

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Look into a product called torque seal

rockclimber said:

It will make no difference whether or not you weld a washer on the outside.

That's not how control arm bolts work.

They are there to clamp the ca mount to the bushing sleeve. That relies on the inside surface, nothing on the outside matters

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The weld washers are welded to the CA mount, not the bolt
Extremely common procedure on Jeeps due to the paper thin mounts lobing out over the years.

A few years ago I had tonnes of lower CA movement due to lobed out mounts. I unfortunately didn't have a welder handy at the time, so I took it to a guy to have some washers welded on. They weren't proper weld washers (usually very thick and minimum grade 8) but just regular old 9/16 washers. They may be lobing out as well as they're only as thick as the mount metal.

That said, I ordered a bag of 9/16 weld washers just in case. Will be under the Jeep to take a look this afternoon.

blistovmhz said:

The weld washers are welded to the CA mount, not the bolt

Extremely common procedure on Jeeps due to the paper thin mounts lobing out over the years.



A few years ago I had tonnes of lower CA movement due to lobed out mounts. I unfortunately didn't have a welder handy at the time, so I took it to a guy to have some washers welded on. They weren't proper weld washers (usually very thick and minimum grade 8) but just regular old 9/16 washers. They may be lobing out as well as they're only as thick as the mount metal.



That said, I ordered a bag of 9/16 weld washers just in case. Will be under the Jeep to take a look this afternoon.

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:doh:

Welding washers to the outside will not help.

I repeat, that is not how control arm mounts work.

The bolt clamps the mount around the bushing sleeve. The entire system operates on the friction between the INSIDE faces of the mount and the bushing sleeve.

NO amount of crap welded to the outside faces of the mount will help.

Re: Re: Loud pop/clang during articulation - XJ

rockclimber said:

:doh:

Welding washers to the outside will not help.

I repeat, that is not how control arm mounts work.

The bolt clamps the mount around the bushing sleeve. The entire system operates on the friction between the INSIDE faces of the mount and the bushing sleeve.

NO amount of crap welded to the outside faces of the mount will help.

Click to expand...

False. Bearing stress still exists on the bolt, and while the bearing stress is much less than that of the shear stress between the mount and sleeve, it still serves to properly orient the control arm in the mount and keep it there.

And if you do the math to determine the clamping force and friction coefficient, the result is that the friction between the sleeve and the mount is about 20x too little to even hold the control arm under mild braking conditions.

x-jay vision said:

False. Bearing stress still exists on the bolt, and while the bearing stress is much less than that of the shear stress between the mount and sleeve, it still serves to properly orient the control arm in the mount and keep it there.

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That has nothing to do with welding washers to the outside of a mount with wallowed holes. Wallowed holes are a sign of over or under torqued bolts.

And what keeps the bushing or joint in the mount is clamp force. Noting else. Don't think so? Go out and loosen the bolts on your rig until they are just hand tight, see what happens.

CA bolts are not locating pins, if they were every one would be press fit in the mount and bushing. They are clamps. They clamp the sleeve inside the CA mount

blistovmhz said:

And if you do the math to determine the clamping force and friction coefficient, the result is that the friction between the sleeve and the mount is about 20x too little to even hold the control arm under mild braking conditions.

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Bullshit. if it wasn't you'd have stockers bending bolts and breaking mounts.

My rig with the big brakes and JJs on all 4 arms would be tearing through mounts if that were even remotely true.

Heims heims heims oh heims. Check em.

Re: Re: Loud pop/clang during articulation - XJ

rockclimber said:

That has nothing to do with welding washers to the outside of a mount with wallowed holes. Wallowed holes are a sign of over or under torqued bolts.

And what keeps the bushing or joint in the mount is clamp force. Noting else. Don't think so? Go out and loosen the bolts on your rig until they are just hand tight, see what happens.

CA bolts are not locating pins, if they were every one would be press fit in the mount and bushing. They are clamps. They clamp the sleeve inside the CA mount






Bullshit. if it wasn't you'd have stockers bending bolts and breaking mounts.

My rig with the big brakes and JJs on all 4 arms would be tearing through mounts if that were even remotely true.

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Okay man thanks for the knowledge! I'm gonna use slotted lower control arm mounts from a TJ now so I can have caster adjustability.

Meh, either way. I've had the problem before, I've solved it many times with weld washers and it's held up for quite a few years. First one I did was 8 years ago, and it's still on the road and on the trail, and the holes haven't wallowed out again at all. My current rig had the same issue when I got it. Left control arm mount was lobed. Welded in some washers and it's still good. Didn't do the passenger side at the time, and they're lobed out now as well, but the drivers side is still dead tight, though 60,000km highway and 3-4 years of hard wheelin'. Maybe my mounts are held together with good intentions.

831_xj said:

Heims heims heims oh heims. Check em.

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Checked, many times. Only Heims in use are for the track bar. Problem has existed through 3 different track bars. The current is massively overbuilt because I thought TB was the issue originally. Brand new heims on, all extremely low tolerance. The only thing it might be is the heims rolling and knocking into their mounts, but I haven't seen that happen on camera yet, but still get the pop.