Strange "thunk"...I'm baffled

[XJINGA]

Put my stock 2000 XJ on a lift and thoroughly examined everything...ball joints, wheel bearings, etc. Installed new front shocks, Everything seems fine and all lube points have been paid attention to during my ownership. Control arm bushings are fine, axles and joints are solid. Here's what is happening....when my right front wheel hits a bump or pothole, I get a weird clunk and just a touch of wobble, as if something is loose. It's not too bad or loud but enough to tell me something needs looked at. It doesn't happen if the drivers wheel hits anything. Also, if I hit something head on like a speed bump where both wheels hit at the same time, the thunk doesn't occur. I can almost sort of feel it just under the floorboard by the gas pedal although it sounds like it's originating from the right front wheel area. Best guess at this point is the track bar. Any opinions? Thanks.

[CharlesS]

IF you still have the stock upper control arms... I would check the condition of the rubber bushings..... They are known to crack and decompose after years of heat and abuse... This would cause the noise you are referring to when the load is removed and applied to the control arm bushing....

Charles

[POSXJGuy]

i had this same annoying ass noise on my cherokee and it turned out to be my trackbar. i got under and tightened everything up real good. if you have the time take it off and grease the ends before installing it again. that'll get rid of some noises.

i think all xj's have a weird noise here and there

should be an easy one to fix.

if you hear metal to metal creaking that is when i would be worried.

as for clunks and thunks... i think its probably nothing big.

[POSXJGuy]

last night , weather was cooler, my friend wanted to troubleshoot his POS so we looked to see what was making noise. of course its not something you can locate just sittin in the garage so we proceeded to check every bolt we saw. the culprit was one of the following:

- steering box , somewhere between loose and decent
- motor mount bracket to unibody , loose
- track bar at unibody , needed tightening
- track bar at axle , decent
- grease gunned every zerk fitting , needed lube
- tightened the bumper mount bolts, decent
- checked the LCA and Upper CA bolts. , decent
- motor mount bolts , they were loose too
- pitman arm, loose even after we had loctite red on it last time. 1/4 turn

i know it was probably overkill to just go around tightening and checking everything instead of doing one thing and driving but frankly i was sick of his sh*t. we just torqued all things down without going cowabunga on em and snapping em.

the noise was gone after that.

if after doing those it was still there i would then start on the tie rod ends, steering parts and hubs etc...

we are pretty lazy so i wanted to do all the lazy stuff first. by some miraculous feat we found it and didnt even know exactly what it was. oh yeah, i also lubricated all bushings as well with silicone lubricant spray.

i am a firm believer that things around the motor and front end just work their way loose from movement, vibration and just plain backing out. i have even had loctite red on some parts and they still came loose from chemicals getting on em.
in all it should be a easy fix. then when you do it you'll always remember to check those parts again after. i do now.

[SoIL4x4]

If you have tried everything mentioned previously with no luck jack up the front end and grab the top of the wheel and try to move it back and forth
(towards and away from the wheel well) if you have play or wobble it could be the hub or unit bearing (same thing some parts stores have different names for it) it will usually only make noise when you hit bumps. I have a 97 with no rust any where except on the stearing knuckles so getting these off was a total pita I tried everything it finally took the air chisle to pop it loose, after that this is an easy fix, oem bearings are about 120 from auto zone, while you have these off you might also want to check your axle shaft u joints too, its easy with the bearing out the shafts just pull right out.

[XJINGA]

Problem fixed.

A $4.00 sway bar bushing was the culprit.

This we discover after changing all the steering linkage, control arms, track bar, etc. The "thunk" was still there after all that and the sway bar bushings were the only thing we hadn't swapped out.

Lesson learned....never overlook the little things. At least now I have all new everything under the front and won't need to worry about that for a while. :D