Ok guys,

After a recent wheeling trip my Jeep has developed a knocking / low clunking sound up front brought on by potholes and similar bumps. I've had someone turn the steering wheel and I can't see any points of looseness. I checked the ball joints...they felt fine. Track bar was still solid (stock and has a fairly new poly bushing) no wallowing that I can see. Draglink is tight. Control arm bushings all seem ok (running WJ Arms btw). Shock bushings we're all tight. Motor mounts are in good condition. Sway bar links removed or installed yields the same results.

Is there something I'm missing?

 

Shocks, perhaps...

 

Bar Pin Eliminator time?

 

Have someone turn the steering wheel back and forth while keep your fingers on the unibody frame rail just aft of the track bar mount. If you feel a definite thump, here's what you do.

Under the drivers side motor mount bracket there are 3 bolts that that go into the frame rail. Grab some tools and get busy tightening them.

 

Didn't think about the TB mount...thanks Frank! I'll check it out tonight.

 

is there some play in the control arm bushing and the bolt?
that drove me crazy 1/2 bushing with the stock mm bolt , knock knock

 

Is there a fix? I'm guessing larger bolts? If so, what size? Thanks!

 

If the T/B bolts are tight, check the ones I mentioned.

 

Yep!

 

1/2 " grade 8 bolts did the trick but you have to drill out the mounting holes, check it out , one way to tell is tighten them up and drive it around
and see if it does it, when it gets lose again it will knock.

 

How close is the exhuast to the front crossmember?

 

Well, TB mount was solid. I wrenched on every bolt I could find, nothing was really loose. But, I think I've found my problem. The WJ upper control arms I use run the same diameter bolt as an XJ, so I was told. I think they loosened up a bit and allowed the bolt to "swim" in the bushing. I'm going to get some larger diameter bolts and drill out the holes if need be.

Can anyone tell me the diameter of stock UCA bolts off the top of their head?

Thanks again guys!

 

I actually would like to thank you as this may be the reason I am having similar noise. Although i dont know the diameter off the top of my head. Pull it out and go to lowes and buy a few bolts of similar length diff diameters and test em out and return the ones that dont work

 

Actually, I've got an old bushing that I'm going take with me, then I can find the exact size I need to make it work. Only have to monkey with the length then, which isn't as critical as long as its long enough.

Glad you found the post useful. People on here are beyond knowledgable! With the exception of myself, I learn most everything through trial and error! LOL

 

I had installed an RE3.5" kit in my XJ which came with new lower control arms. I had a bang since I installed the kit. I changed the bolts in the lower control arms where it sounded like noise was coming from but it turned out to be the bushings them selves. Rubicon said they had a bad batch of bushings.They sent new ones and it solved the problem. Check the bushings. Could be a similar problem.