Last night I replaced my front end links which cured the clunk from those being bad... but I still have a clunk in the front left. It's relatively quiet and only occasionally exhibits itself over potholes. It's most apparent when I'm turning at low speeds going over seams in the road, like pulling out of my driveway.


I've gone under my car and pulled on everything by hand and with a prybar and can find nothing loose, neither could the alignment guy at VIP. It drives great, with a minor wheel vibration at 45 and again at 95 (been chalking that up to slightly warped rotors or possibly slightly bent rims), but feels solid all the way into the triple digits... Except for when I go over a pothole, the clunk occurs and I can feel it in my wheel.



I've replaced within the last 2000 miles:
Moog Inner + outer tie rods
Moog end links
Mevotech lower ball joints
Whiteline LCA, CR bushings
Energy steering rack, sway bar bushings
KYB Struts w/ stock springs.
Tightened up steering rack, no leaking



After an inspection of my front suspension I can only find one thing that looks "wrong" although there is no play I can find with a prybar. My right Whiteline compression rod bushing is slightly separated on the top of the rod when the suspension is unloaded, probably about 3mm of inner bushing exposed in the vertical direction. I figure this is due to my right compression rod nut not being torqued to spec as the stud has some destroyed threads that I suspect are where the nut "should" be. I haven't tried torquing it to spec as I don't want to break off that stud on my daily.


The other possibility seems like the compression rod ball joints, which I judged to be "ok" when I pulled the rods last. They did feel looser on center than anywhere else in their range, but not as bad as my ball joints which only occasionally knocked during hard braking and take a lot more stress.





TL;DR / Questions:
If I were to attempt to torque down that stud and the stud snapped off, or even worse the nut started to spin, is there a way I could quickly fix that in my garage without using a welder or any expensive tools? The only way I would attempt this is if I had everything I needed to repair on hand before I started torquing. If this is the cause of my clunk, I can live with it.


How would I test my compression rod ball joint to determine if it is the culprit?


Could the noise simply be the cumulative effect of my 19" wheels and poly suspension bushings? I'm tempted just to spray a bunch of rubber undercoating around the area and try my best to forget about it until it starts getting worse.

 

I'm betting it's the upper control arms, either the bushings are shot or the ball joint is slightly worn.

I would focus on the vibration problem first though, it's easy to pull the rotor and check it for warping, it's easy to run the tire down to someone with a road force balancer to have them check it for potential problems.

 

The vibration is tiny, almost imperceptible which is why i haven't dealt with it and it's literally only there at exactly 45 mph on my average commute. There's no bad vibes in the brake pedal and I've got plenty of braking power to activate abs easy. My pads probably have 6 months left on them so I'll put on new rotors when i do those, wheel bearings as well.

I'll take a look at my upper arms again, but if they seem fine i think I'm going to ignore it and take another look after it inevitably gets louder after 2000 more miles

 

I had 130k mi UCA's that made a slight noise, when I replaced with Kinetix arms it went away. I agree.

 

Exactly what I was gonna say. UCAs are always overlooked because everyone is always putting their attention under the car.

Also, why would you ask about breaking the comp rod stud mount? It should be tightened to ~165 ft/lbs. No more. I have seen ways of people fixing it, but as a safety issue, I'm not even gonna entertain the question unless that bridge absolutely needs to be crossed. Just don't tighten it anymore.

All that being said, a very likely source of this could be just a loose bolt somewhere. You would be wise to go over every bolt in the suspension including (but not limited to): all 4 bolts on the UCA, the two bolts and ball joint nut on the UCA, the shockmount nuts up top, all the chassis brace bolts and anything else you want to just check. Sometimes bolts back out and I've had UCA bolts back out once and it caused a really bad clunking that took me awhile to zero in on.

 

If I replace my UCA with a 350z part am I correct in assuming that my camber will be set properly for 350z stock springs? If so, this might be a future upgrade I can install at the same time as the springs. The only thing stopping me now is the cost of a quality front camber kit relative to the cost of fixing other issues with my car or adding an upgraded sway bar.



Scraggle my right hand side (side that clunks) comp rod nut is at around 80 ft-lbs currently as the stud was damaged by a PO's repair (absolutely destroyed threads, reduced thickness of stud to about 2/3 original diameter in that area). When I was torquing it I started to get an uneasy feeling (compared to the other stud) that I was about to strip or snap something, so I stopped tightening it. I was asking about repair options because I'd like to have that knowledge/toolkit on hand if I were ever to attempt to tighten that bolt to spec.


Last night I went through and tightened everything up, nothing seemed loose. I paid special attention to the comp rod and UCA balljoints and couldn't find any play again. The comp rod ball joint boot is torn (plenty of grease though) on the clunking side so maybe that's starting to wear out. Can I 100% verify this somehow by taking the balljoint out of the knuckle and actuating it?



I'll be beating the crap out of the G in the coming weeks in a couple autocrosses and several trips to the NH mountains, so if this noise gets worse and causes me to go after it again I'll update with any fixes.

 

Ok, the non welding method I've seen is this: a guy got a hardened bolt the same diameter as the original stud, cut off the original stud and drilled into the chassis. Then he tapped some threads into the chassis and screwed the bolt into the chassis (probably with ultra-mega-super threadlock). He cut off the head of the bolt ince it was secured into the chassis and made threads on the nut side to bolt up the comp rod/chassis brace.

 

Sounds like a lot of fun. No thanks.