After looking tonight I am going to my mechanic tomorrow to get their $0.02 but need to get opinions because suspension can feel like you are chasing your tail.

05 Z with 202,000 miles on it. So far on front end stuff-
about 2-3(?) years ago got a small rattle noise from the front end going over sharp small bumps. Took it to mechanic 2x, found nothing. Looked at it myself once a week several times. Finally did compression rod bushings (factory style from Nismo) because I finally saw some cracks in the rubber. Much quieter but not perfect. Had to let it go for a few more months until I could see the knuckle flex when I re-torqued lug nuts with the car on the ground and replaced the whole compression arm with Oreilly arm. Found it by accident. Ball joint was visibly loose finally and obvious what was wrong. Car had always driven perfect except for the noise!

Everything seemed perfect after that. But that arm only lasted a few months. Also had the right side go out. Replaced with Oreilly. It lasted 5,000 miles. Replaced both arms one more time in only a few months because of more rattling. Always on the left side, only once on right. Or something like this, I can get out my receipts and service records I keep. No other problems or symptoms. Returned them both last fall for full refund and bought OEM arms and SPL spherical bearings. At the same time put both Whiteline bushings in transverse link arm.

Everything seemed great. Thought I would be done with those for a few years buying the good stuff. In the last several weeks, my original shocks finally showed signs of needing to be replaced so I did it last weekend. When I was waiting for my parts to come in things started to rattle a little more and suspension started to deteriorate a little more cornering hard - little sways or wiggles I thought I could feel. Also noticed that the steering wheel is now vibrating very slightly at high speed (over 75mph). Also once in awhile when braking in town with normal pressure I could feel a slight pulsing in the braking. I thought the brakes were pulsing with the worn shocks but the brake pulsing is still there after new shocks. It's so slight I am not sure if I feel it in the steering wheel or my seat. After doing all 4 shocks, the rattle is now obvious to me that it is the left compression rod ball joint now. And I have tried to look for other things and think my right inner tie rod has play. That could explain the brake pulsing and the vibration on the highway right?

Only other major thing done to front was driver side wheel bearing before any of this came up. That was a little noisy like they typically do when you turn one way, then while I was waiting for the part started howling very loud down the highway. Right bearing still feels and sounds fine to me.

So part of this will end up being done hopefully from some professional advice but seems like suspension diagnosis is extremely tricky to catch things before they destroy something else or detect anything wrong at all.

I'm thinking that the left compression rod and right inner tie rod need to be replaced. The car will be quiet again-that I'm 99% sure. Maybe the tie rod will take care of the vibration and the brake pulsations.
But what things can cause the other things? Was the tie rod always going out for the last year and I couln't detect it. Did it blow out all of the previous ball joints? If my mechanic agrees about the tie rod do I really just need to do myself a favor and replace inner and outer on both sides and the compression rod? And what else could be 3-6 months away from being a problem that I will finally detect? Seems like another big gamble and guessing game

Please give me some advice or an education

What I really need to understand is what parts can wear out other parts. And what ones can I separate out that this part could never wear out that part. How do I separate multiple symptoms and parts and systematically diagnose each one? The manual is not much help when you just pry on all of the ball joints and wiggle the tires. That is for when it is so shot it is obvious. This tie rod has been the first thing that I have ever been able to detect. And it wasn't until I lifted only one side and locked the steering wheel that I could finally convince myself it was the tie rod and not me moving the steering wheel from outside the car.

 

My mechanic says the brakes are warped, the front tires are cupped, and the compression arms just wear out quick. Advised me conservatively that it will never drive 100% new again so concentrate on only the things that are really wrong and matter. He said it drives great for 202,000 miles and thought it was all good. Personally wouldn't do anything right now.

This doesn't tell me how long to let the rattling ball joint on the compression rod go before I finally do replace it. This arm basically holds the front caster in specification, right? Right now it is only over cracks in the pavement under 25mph so no big deal. Since I have SPL bearings, I will never get to the point where the car won't track straight or won't hold an aligment like with rubber bushings. What symptoms would warrant a replacement finally?

Also as much as I trust his advice, after really looking closely at my car tonight, only one of the front tires has worn too much on the inside tread. And if they are one or both cupped I cannot feel it. My first thought was aligment issues but that is also a perfect sign of a bad shock to be cupped and only one side. I think in the past both front tires wore on the inside if the alignment was off. I read a great article on StopTech about how rotors never warp and 99% of pulsing is caused by pad build up on the rotor and can be sanded off. I was fully prepared to do this because I do have imprints of partial pad patterns left behind but what bothers me is 3 rotors feel smooth and the rotor with the cupped tire has grooves in it that I can feel. And this is the same side with the tie rod. I'll have to report back if grooving is on both sides of the one rotor or just the outside I can see. Not bad just noticeble. I will also need to check the pads and caliper slides are OK tomorrow. The pads look even from looking at all the edges but know they need closer inspection than that. My calipers are not as old as the car. Seems like around 150,000 I got remanufactured ones because originals were sticking.

Since I still don't know how to track all cause and effects of a suspension system, I am convinced that I should do a little something before I beat up my new shocks. Also should not just assume new shocks will cure whatever caused the tires to cup. After all, I believe I am in the situation I am in now because I don't have the eperience to know what cause/effect relationships exist. I feel like now that a more aggressive mechanic could have helped me avoid a few things over the last couple of years when I came in for my tires or an alignment that was needed.

Anyway, tomorrow I will put my snow tires on the front and take it out to the highway to see if vibration of steering wheel is gone. If not I will still suspect the inner tie rod because I can feel slight play from 3oclock 9o'clock direction with only one wheel in the air and the steering wheel locked and a helper. I don't think my mechanic looked at that fine of a level. He found no obvious play. I have reason to doubt that diagnosis a little because I've seen it myself.

I now also believe letting the shocks go for so long maybe caused the compression rod ball joints in the last couple of years to go out plus the right tire cupping/wear uneven on the inside - whatever anyone wants to call it. What I cannot figure a relation to is the rotor grooving. This is the first time I've used Autozone pads/rotors so it may be a little cheapness and pad transfer but I bought the expensive grade of the house brand. All other brakes have been EBC and never had any "warped" feeling in the brake system. Could there be any relationship between rotor grooving and my other symptoms or is the rotor problem isolated from everything else??
Could a tie rod and rotor grooving be related?

I am thinking the worn shocks caused many ball joints to go out and caused the inside of the right front tire to wear unevenly or even to cup. If any of this occured for a long time I would believe that the tie rod then wore but I've only just recently had the vibration and brake pulsing. Here I thought new shocks would most likely make those two things go away. Looks like I waited about 6-12months too long to do replace shocks before they caused problems. Although it is not a crystal clear lesson, lesson learned

 

With the snow tires on it is smooth well over 100 and no brake shakes at any speed that I can tell. I remember my mechanic saying that the brakes were warped and they caused the cupped tire(s) and is why I'm keeping after it some more. So, maybe not. Just worn out shocks. And the snow tires still look perfect and the summers I don't remember seeing anything wrong when I put them on in May. I guess I've just had my head up in the clouds all summer worried about too much at work and other things at home. I guess this ended up being a place to dump my brain but maybe somebody will be in a similar situation someday At least someone learn something from me. Apparently my shocks finally gave up in the last 6 months and I just didn't pick up all of the clues until they ruined the tires in the last month.

I just have to figure out now what tires to use so I don't have to shake down the highway and risk wearing out new suspension pieces until November when the snows go on. Due for new summers all around next year anyway. I can handle that much right now though! Wouldn't hurt to check out all of the calipers too since it's been a couple of years for brakes. don't want any sliders sticking.