I have got the shakes! Must get to the end of my vibrations.

[elwesso]

Well, ive been living with this for long enough.. Im getting oh so very sick of my car shaking!

Just FYI, most you know that I am pretty sensitive when it comes to this kind of stuff, but I dont care... I think tech would have a heart attack if he was in my car.....

Now, onto the particulars.

What has been replaced since I have owned the car- Driveshaft with one from power-train industries.- entire brake system (literally EVERYTHING but the hard lines and MC)- Suspension (you all know whats going on with that)- Right rear wheel bearing (not sure it needed it but someone recommended I do it, so i did)- Current wheels on the car (stock 15s with firestone firehawk 235-60) were rebalanced about a year ago, and were put in storage. Hopefully theyre still ok, i think they probably are.- engine, trans, and diff mounts about 30k (when engine swap was done at 88k, car now has 125k)

Problems:

- EVER so slight vibration at 40, its hardly noticeable and it doesnt bother me. Id dare say most on this forum wouldnt even notice it.- There is also another slight vibration at 60, very similar to the one listed above.- at 60, the wheel shimmies just a TINY bit.. rotors seem to be warped a little, which is odd because they only have a 5-6k on them, maybe due to the cheap pads on them.- Things start getting ugly above 90. By and large, teh car is really smooth from from 0-85mph, which is where i spend most my time. However at 90 and on, another vibration starts... It feels similar to the ones listed above, but its more intense. This is noticeable...- ONce you get around 120, seems like the front end likes to shake, and by now the car is shaking good... The vibraiton seems to come and go as you go up to 140... Meaning it might get a little less at 130, then come back at 135, and so on... this isnt exactly how it is, just an example.....

None of the repair shops I deal with are coming close to compitent to figuring out whats going on. I mean, wheel bearings barely ever fail in Q, especially in the rear.

I still have 6 months left on my driveshaft warranty. It came with a 1 year, million mile vibration free warranty.....

[Falkdesigns]

Cheap pads won't warp rotors.

IMO, it's either bearings or wheel balance, especially with the way you describe it. Could be a bent wheel. If they weren't hub-centric wheels I'd say it could be that, but I know they are hub-centric, so that's out. Do you get this vibration with both sets of wheels you run, or just these winter wheels? If it's both sets, I'd replace my wheel bearings all the way around. If there is any play in ball joints, replace them, but I think you've done all that.

I'll tell you what, I'm at least as sensitive to vibration, sounds and anything out of the ordinary as anyone I've ever met. I feel and hear everything, and sometimes, it's just annoying, and I wish I didn't, lol. I'll have someone with me and be like "you feel that?" or "do you hear that little sound coming from the right front corner?" and the answer is almost always "no". Once I hear or feel something, it's like I totally zone in on it, I always thought I'd be perfect for a MFG's NVH department. On the plus side, I can almost always figure out exactly where something is coming from.

[Q45tech]

I rotate and balance every 90 day oil change, and retrue the rotors every 2nd oil change...........sometimes it takes every 6,000 miles on rotors.

Necessary to meet oem runout specs.

By replacing both kingpins and their bearings [plus the 3rd link the kingpin sits in] solved alot of residual vibrations.

Most cost effective to buy NEW 3rd link which has new bearings then the new king pin................fast to swap out and torque to spec.

What is cold vs hot radial force on tires less than 10 lbs is spec. Few except Michelin can meet this number USED and even Michelin cannot do it cold [after sitting with weight on tire overnight at 32F].

Vibrations that change [holding speed constant] for first 15 minutes from cool statup are always tires as that is only thing that changes stiffness and diameter as they warm up............rotors do the same to a lesser degree as you use brakes and temp increases.

Not to say mounts [engine and transmission won't change intensity some due to heat up] but not frequency.

[FarFetched]

To me it sounds like DW (dead wobble) case. May lifted vehicles have this problem. Sometimes a normal(not lifted or lowered) vehicle gets this disease which is hard to get rid of.Another point that not all tires created equal - meaning that one tire of 4 on the car could be a bad seed. I've had this issue with BigO tires where one tire had a cavity(barely visible) where sidewall merged with protector causing vibration at different speed. After several arguments with Manager of BigO tire store, I got set of new rubber and was happy ever after. Where exactly is your vibrations located?Describe vibs as precise as you can.

Incorrect suspension geometry will give different symptoms, however, it not unlikely to have similar shimmy/vibrations if your toe is out of wack or you have incorrect SAI or castor is way negative. Who knows!I can only speculate on it!Don't give up Cheers!

[Aussie Q45a]

Hey Wes,Got the exact same problem. Had all the wheels balanced but still have the same vibration. When my tyre man rechecked the wheels he found them to be out of round and buckled just a little bit. I have to take them to a bloke that has a wheel lathe to have them straightened. Have you tried another set of wheels? My tyre man loaned me a set just to prove that it was a wheel problem.

[elwesso]

Thanks guys for the quick response....

Tech- i can definitely tell when the tire-related vibration goes away. See the thing is, since im in school, the car hardly ever gets driven (flatspots), but when i DO drive it, it is generally over 20 miles......

I am suspecting my trans mount, even though it is newish... Sometimes when I have the car locked in 2nd going about 60MPH, and i come abruptly on and off the throttle, i can hear a clunking, and it seems as if its right by the seat (where the trans bolts to the X-member)

I defintely think that if the wheels/tires are out of balance, its in the tires. Fred told me that when he got these wheels, a guy took them off his 95 Q and were fairly new.... I dont recall if my 350Z wheels had the same vibration, but I dont think it did... if it was, it was not as intense. However, i am thinking that maybe these solid tension rods just simply transmit more vibrations!!!

No big deal, as I have a set of michelin pilot sports going on all around.... Hell, i even have a set of brand new M45 wheels that I just bought off ebay (the Y34 18s, won for $136 shipped!! )... I am not concerned about the wobbling from the front end.... When I get my wheels and tires situated, i should be all good. plus ill have my rotors trued.

Thanks also for the info about the 3rd link. I definitely will consider that.... I have 2 extra 3rd links with wheel bearings from my old Q.. Do you think that it would be equal for me to buy the kingpin bearings and so forth, and just install them in those, and then install the freshened assy in the car? Im not sure what the nomenclature for this is on Joe's website, but i will pull the part number later and get some pricing. However the entire kingpin assy is only $20.. I can live with that!!! Total with the bearings and oil seals its only like $60 per side... no biggie. I also have access to a press if i need it, but i dont think i do. I dont have my FSM or parts book with me at the time, so ill have to look at this stuff at the 1st of the week.

FF- My alignment is perfect, i made a post about in the Q forum, im running -1* rear camber, -1.4 front camber, 0 toe, and 7* caster

What I am mainly concerned about is the driveline vibration that I am getting... as stated earlier, its intensity is very low until I get to about 90MPH, then it really starts to intensify up until you reach X mph.

Important to realize that the frequency of this vibration is constant throughout 40-X mph, it just varies in intensity.. i am also forgetting about the wobbling problem, as I think i can narrow that down easily. This sure is not much fun trying to trace down a bunch of vibrations from all over the place!!!!

[PopPop]

I was thinking the same about the king pins. Put the front end up and move tire north and south from the back side or have someone move it why you look from back side of wheel. Q 45 Tech you said the 3rd link comes with bearings and king pin or did I miss understand you. Plus replacing king pins aren't that easy of a job. When they are bad most time water gets into the joint and causes rust so if you do it your self. Be prepared to do some heavy pounding too separate king pin from its joint. Plus the torque spec. are very high also.

[Q45tech]

Third link comes with bearing then buy kingpin. Less than $150 with discounts.

Non rusting kingpins..........whole job takes an hour per side with experience and lift and every tool.

Making a car with 60k on it perform like a new one requires a ton of new parts.

Don't assume brand new OEM wheels meet specs without testing them!Transport problems without tires to protect them.

[elwesso]

Thanks Tech... So it looks like it will be about $350 or so to replace everything... I think i am going to consider buying the bearings, kingpin, and so forth and swapping them into my spare 3rd links...

I think i can safely say i can get the wobble taken care of once I true the rotors, have my new tires balanced and installed, and then replace the kingpin/bearings.... So that issue is taken care of.. if that doesnt fix it, i will consider replacing the outer tie rods... so thats taken care of..

Now id like to shift focus on the driveline.... I will replace my trans mount and see what happens with that... assuming that the trans mount does not change anything, what else should i be looking at??? im almost thinking that if the new trans mount does not change anything, then i need to look into having my driveshaft replaced again....

[texasoil]

A vibration that is not 'resonant', which is what you describe, is almost aways either run-out /out of round caused or simple imbalance. A driveshaft vibration will be much higher frequency than a wheel/tire. Have you checked for a bent hub? Check the run-out (lateral and radial of each wheel as mounted to ensure they are all true and round --on each side. Bent rims can be a bear.

I once chased a persistent higher speed vibration all over, finally changing tires--and it went away!. Even though the old set was balanced and true at 'balancing speed' , apparently they were not at higher speed. If the tread does not appear sharp when running at balancing speed, the tire is not round. I could 'feel a squirm in a very slow speede sharp turn on a smooth wet parking lot. Must have been twisted/loose belt.

[elwesso]

Id really like to get a frequency sensor or something like that (oscilliscope?)o that I could post it... IE graph it based on the sine curve...

I can say that the vibration im referring to was no worse or better with my 350Z wheels or stock wheels... I would think that one set would be better than the other, either way (either stock is better or the Z wheels were better, highly unlikely they would both be similar?)....

The frequency difference between the tire "wobbling" vibration i feel at 100+ is quite different. If I were to picture the graph of this vibration in my head, i can easily identify the nodes of the vibration, meaning the frequency is much less than the other one.....

I know that one rear tire is out of round on my Z wheels, because it is starting to bulge where a patch was. Glad i caught that soon, will be replacing those tires ASASP!!!!

The one im concerned about has a much higher frequency, however, similar amplitude....

[FarFetched]

Do you get dronning high frequency vubration besides the wobble?If it is constant look into imbalance or DS incorrect driveline angles (which includes damaged supports for eithr transm or diff). Does hight frequencey correspond with engine speed (of course in 1:1 trasm gear) or does it correspond with vehicle speed?Do you feel it in the seat/feet/ along the d-shaft tunnel?

Cheers!

[elwesso]

Do you get dronning high frequency vubration besides the wobble?If it is constant look into imbalance or DS incorrect driveline angles (which includes damaged supports for eithr transm or diff). Does hight frequencey correspond with engine speed (of course in 1:1 trasm gear) or does it correspond with vehicle speed?Do you feel it in the seat/feet/ along the d-shaft tunnel?

Cheers!

yes it is besides the wobble.....

The frequency never changes, just the intensity, and it is related to vehicle speed, not engine speed.....

[elwesso]

Well i just got off the road, drove the car for roughly an hour at highway speeds, and Im starting to think this is more of a suspension related problem... im DEFINITELY going to buy the stuff to replace the kingpin...

At 90MPH, it seems that the vibration was more prominent through the steering wheel vs when i put my hand on the carpet near the tunnel. There is a lot of foam right there but still....

I just looked at the parts, and it appears that the complete 3rd link aka "knuckle" assy is only $85... for $100 per side including the kingpin, that seems the way to go... the question is if everything comes pre-greased and all that stuff, and all I have to do is put the kingpin in..... hell its almost cheaper to do it that way...

The only problem is on Joes site, it lists a part for "knuckle assy", which is $243 each... I wonder what that part refers to.

The part code that I got lists "EXTENSION COMPL-KNUCKLE ASSY" which would think that it includes the bearings included and everything......

According to Tech this assembly listed, which I double checked part numbers on joes site for $85, should include the bearings in it, and then i just replace the kingpin.....

[PopPop]

Wes don't get the parts mixed up! Some people call lower control arm 3rd link! The lower control arms comes with outer tie rods and inner bushings. Your sway bar will attach to this and spindle.

[elwesso]

My nomenclature is all taken from the FSM and parts book.

[PopPop]

3rd link is the vertical unit that attaches to upper link. Lower horizontal arm is the transverse link.

[elwesso]

3rd link is the vertical unit that attaches to upper link. Lower horizontal arm is the transverse link.

Im aware of this.

[PopPop]

So what problem were you having with Joe's knuckle assembly for $243. The knuckle assembly is the 3rd link! You know for yourself that prices vary.

[elwesso]

Well because the parts book showed the part as the one for $80, but i just dont know if it it includes the bearings in the kingpin.

The part number from the parts book that i pulled on Joes site leads me to belive the part is $80, but afte rlooking at Joes site i just dont know..... Ill have to call him.....

[PopPop]

I'm interested in seeing what he tells you Wes! The $80 is most likely just for the Knuckle itself but, $243 is for knuckle and lower control arm ( transverse link ). Still bearings is another mystery until you speak to Joe.

[elwesso]

Ok heres a diagram

Were dealing with part code, according to that diagram, 54590 and 54591

The part numbers are as follows

54590-66U25- EXTENSION COMPL- KNUCKLE ARM RH (alternate part number 54590-66U25)54591-66U25- EXTENSION COMPL- KNUCKLE ARM LH (alternate part number 54591-66U26)

I know this is what I want, because it is what is in the FSM.

AHH I figured it out and I was right... The knuckle assy is aka the spindle..... THAT is what is $243... The KNUCKLE ARM is the $80 part...

It would make sense that the part in the diagram above would include everything, because in the section diagram right before thta in the parts book, it listed all the seperate parts for the kingpin, such as the bearings, cap, and so forth.

It would have been easier to believe tech, but i feel better that I proved it.

So for the next person, the KNUCKLE = SPINDLE, and KNUCKLE ARM = 3rd link.

[maxnix]

Well, I hope this cures it. And I hope the collars you put on the rear subframe aren't masking something out of whack there that is causing you to think the front end is wandering at speed.

Good luck and please let us know.

[elwesso]

Brian, with my pre-research i did with subframe spacers, it actually causes the subframe to line up BETTER with the driveshaft..... This is part of the reason that when replacing the subframe bushings with poly, they feel much more secure... Refer to the diagram below...

This is the best I could do with MS paint... its very crude but it gets the point across...

on the diagram at the top, this is how the car comes from the factory..... There is a space between the top of the subframe bushing and the frame of the car..... I could nearly get a finger in between this, id say its about 5-7mm of gap.....

When you install the subframe collar, it simply takes up the extra gap.. thus it eliminates the slop... The reason for the bottom of the subframe collar is to simply stabilize the bottom part of the bushing..... The bottom part of the subframe bushing is really concaved inward... There is a simple washer that holds this on the bottom, that distributes the load across a collar of rubber....

So an interesting note, when you install these it is not metal on metal... The half of the collar that touches the subframe is actually sitting on a rubber hat, not on the subframe or subframe bushing itself......

That is all how I understand it..... What works on paper does not always work in the real world, though.

However, you do bring up a valid case, and I may remove these and see what happens.....

[maxnix]

OK, now I see it.

Anyway, it was not alignment so much, but changing the harmonics of the bushings. If they respond to a vibration at your problem speed, the rear subframe may be moving about and causing you to perceive a twitchiness in the front end. A long shot, but worth considering if the front end work doesn't eliminate it. I remember texasoil (who possesses a great understanding of structures and processes) mentioned the natural primary frequency of the G50 chassis was around 27Hz.

Still, I would do the kingpin knuckles first.

[elwesso]

It helps to see the diagram if you attach it check the post above..

Anyway you do bring up a valid point and I will consider it. The thing is, the vibration was not any worse or better when I installed them back this summer... This was however back with my old driveshaft..... With my old driveshaft, without the spacers installed, it would vibrate at 75mph, and then it would seem to go away at about 85 (however by watching the rearview mirror shake, somehow the vibration was cancelling out, because even though i couldnt feel it so much something was still mkaing the mirror shake).....

With the spacers installed, it simply made it so the vibration started at 85... however, it was MUCH MUCH worse with the old driveshaft.....

Im babbling a lot but sometimes it helps to think out loud, plus the more detail i give the easier it would be for someone else to draw relevance out of my post at a later date.

Im going to have to jack up the rear wheels again and see if i can recreate the vibration that way.... I dont think ive done that yet with this driveshaft installed.

[elwesso]

well tonite for giggles I propped up the rear wheels and it seems like a lot of the vibration is coming from that..... that is, the drivetrain..... id like to find a way to figure out whats ogin on with that, before I mess with the kingpin...

[maxnix]

Did the driveshaft balance by itself? Motor mounts? Drive train alignment? Indexing?

[elwesso]

PTI says they balance the driveshafts perfectly before they send them out, most driveline shops balance at like 800 RPM, and PTI does it at like 1900rpm or something like that.....

Im going to call them, and see what they say...

Im thinking about buying one of those inclinometers before I do anything else, maybe i could shim things and get it to work.

[Q45tech]

There is a reason the two part driveshaft is used on Lux cars: impossible to get the same low level of perfection from a single piece unit [which can be good-adequate but not as good as new oem properly set up].

A single piece can be on car balanced with a strobe and new weld on weights but not without a dyno [to spin wheels against] and pit under [for tester/strobe equipment] to properly create the on road loaded enviroment.