1990 300ZX 2+2 NA

[gugga4u]

Greetings! I'm new to the forum, and have owned by "fairlady" for the past 5 years. I have 2 questions:

1) I bought the car at 65K miles 5 years ago, however, after buying the car, I realized that the odometer is not properly working and thus the low mileage. The odometer is very temperamental and works rarely. Since the speedometer and the tachometer work fine, why wouldn't the odometer register miles? Any help to diagnose the problem would be greatly appreciated.

2) I put in OEM rotors from NIssan dealership in Norwood MA for the fronts. However, within a month, they caved and the steering vigorous shaking came right back i.e. as soon as I put my foot on the brake pedal. Nissan won't take them back so I'm going to install new rotors and break pads. What rotors do people recommend for the fronts that'll last me a few years? Please send me a link or detailed information (manufacturer, model number, etc) so that I buy the right rotors.

Thanks!

[DCaff300ZX]

Welcome!
My NA at times would stop registering miles, as the odometer wheels would bind somehow which a quick jab from the reset button would fix...when I noticed it. Not much you can do there.
As for the "shaking" that's not a rotor issue which may explain Nissan's reaction, as their rotors are fine and I don't know the term "caving". The shaking can come from bad tension rods (common) and also perhaps worn tie rod ends, or both. Bad shocks can also make things worse and the suspension wears similarly so I suspect that your Z needs attention to those areas, which may solve your problem or highlight the actual issue.

Good Luck!

[gugga4u]

Welcome!
My NA at times would stop registering miles, as the odometer wheels would bind somehow which a quick jab from the reset button would fix...when I noticed it. Not much you can do there.
As for the "shaking" that's not a rotor issue which may explain Nissan's reaction, as their rotors are fine and I don't know the term "caving". The shaking can come from bad tension rods (common) and also perhaps worn tie rod ends, or both. Bad shocks can also make things worse and the suspension wears similarly so I suspect that your Z needs attention to those areas, which may solve your problem or highlight the actual issue.

Good Luck!

Thank you for your hospitality and your quick response! Maybe I did a poor job of explaining the "streering shaking" problem, so here are some more details as to why I believe it's a rotor problem. When I changed the rotors, for the first month I was in heaven cuz there were no issue when breaking, no shaking in the streering wheel, etc. After about a month, I started noticing steering wheel shaking, and as time went on, it became worse and worse. Thus I assumed it were low quality rotors that warped within a month or so. If you still think it's a "tension rods" or "tie rod ends" problem, I could have my Z inspected for that.

BTW, any suggestions for a good mechanic/garage in Boston area for a trustworthy Z specialist?

Thanks!

[grayman_TT]

It wouldnt hurt to check all the bolts and make sure they are tight.

Does this only happen under braking or all the time?

[DCaff300ZX]

I definitely would suggest getting at least one safety check and really two, one from a suspension-only type shop and another from Nissan and compare their conclusions. Around here most shops will do these checks for little or no cost, but the dealer may try to snipe you and if so avoid them.
I would lean towards the tension rods, as rotors warping that fast is hard to imagine unless you drive with your foot on the brake constantly or you have a sticking caliper on one side- another small possibility. Another is the upper control arms which when worn allow excess movement in the suspension and shows with excess camber (top of wheel further in than bottom of wheel).
And sorry, I'm on the West Coast and can't help with a Boston Z guy, but hopefully others can.

[gugga4u]

It wouldnt hurt to check all the bolts and make sure they are tight.

Does this only happen under braking or all the time?

It happens ONLY under breaking. All non-breaking times the car is perfectly stable. I drive the Z at aggressive speeds (sshhhhh, sometimes ~100-120MPH) without any issues. So, it's definitely an issue associated with when I put my foot on the break pedal.

[DCaff300ZX]

I took a test drive once with a guy with a 1990 who claimed brand new complete (caliper/rotor/pads/M/C/booster) brakes all around (and after the ride I checked- seemed new) the car would do exactly as you said- ONLY shudder when braking medium to hard and coming down from speed (he was an excited driver, 80+ often). He also claimed new ball joints/LCA's as well but said the rest was original...tie rods, FUCA's, and tension rods, the high wear items BTW.
You can DIY roughly test them by jacking one side of the car CORRECTLY (jacking points under car) enough to release one front tire and leave the other with resistance, "steering" the wheel by hand back and forth any play felt will be the tie rod end(s), or a broken steering rack. Oh, and the rack bushings (loose, missing) may also be the issue which is also somewhat common in higher mileage Z32's.
Also, with the wheel up you can try to "rock" the wheel in and out gripping the wheel and lifting with your leg, testing whether or not the Front Upper Control Arm (FUCA) is worn out and loose, EXTREMELY common. When one thing goes out in the Z32 multilink, everything else needs looking at also.

IMO everything mentioned points to a serious inspection of your front suspension, the multi-link style with it's preload effect makes each part have to handle it's load and do it's thing correctly for it all to work well- so there's my argument as best as I can make it. Hard to see new rotors warping enough for headshaking without some other serious brake problem with the caliper sticking, or M/C issue.

[gugga4u]

I took a test drive once with a guy with a 1990 who claimed brand new complete (caliper/rotor/pads/M/C/booster) brakes all around (and after the ride I checked- seemed new) the car would do exactly as you said- ONLY shudder when braking medium to hard and coming down from speed (he was an excited driver, 80+ often). He also claimed new ball joints/LCA's as well but said the rest was original...tie rods, FUCA's, and tension rods, the high wear items BTW.
You can DIY roughly test them by jacking one side of the car CORRECTLY (jacking points under car) enough to release one front tire and leave the other with resistance, "steering" the wheel by hand back and forth any play felt will be the tie rod end(s), or a broken steering rack. Oh, and the rack bushings (loose, missing) may also be the issue which is also somewhat common in higher mileage Z32's.
Also, with the wheel up you can try to "rock" the wheel in and out gripping the wheel and lifting with your leg, testing whether or not the Front Upper Control Arm (FUCA) is worn out and loose, EXTREMELY common. When one thing goes out in the Z32 multilink, everything else needs looking at also.

IMO everything mentioned points to a serious inspection of your front suspension, the multi-link style with it's preload effect makes each part have to handle it's load and do it's thing correctly for it all to work well- so there's my argument as best as I can make it. Hard to see new rotors warping enough for headshaking without some other serious brake problem with the caliper sticking, or M/C issue.

This is awesome information, Dave! And it's great to know you've personally dealt with a VERY similar situation on another 1990 Z and it turned out not to be the rotors. Your DIY project is easily doable by a novice like me, and that's what I'm going to do over the coming weekend and share with you what I found. Thanks a lot for your help; it's truly appreciated!

Now only if you could find me some Z mechanics in Boston area ;-) BTW, since I just joined this list 3 days ago, I'm curious to know if there's been activity in the past from Bostonions or am I the only [un]fortunate one?

Thanks!

[DCaff300ZX]

An old mod here Tony was a great Z guy from Boston area, but haven't heard from him in awhile. Seems like we had a few here years ago, not so sure any more.

[NolimitZ32]

Tony still beats around the different Z pages on FB, but with him I think life happened so he's moved on.

[gugga4u]

You can DIY roughly test them by jacking one side of the car CORRECTLY (jacking points under car) enough to release one front tire and leave the other with resistance, "steering" the wheel by hand back and forth any play felt will be the tie rod end(s), or a broken steering rack. Oh, and the rack bushings (loose, missing) may also be the issue which is also somewhat common in higher mileage Z32's.
Also, with the wheel up you can try to "rock" the wheel in and out gripping the wheel and lifting with your leg, testing whether or not the Front Upper Control Arm (FUCA) is worn out and loose, EXTREMELY common. When one thing goes out in the Z32 multilink, everything else needs looking at also.

I took your post to my trusted mechanic along with my Z, and he performed a complete suspension check and informed me that it is NOT the suspension, but the darn ROTORS! And then he took me inside the garage, and showed me the problem. With the car up on the lift, he asked me to move the front tire - the tire would not complete a single revolution, and would get stuck mid-way. Basically the highs and lows of the rotors warped, and were making the wheel stuck at certain points of the revolution. I had to put so much force to make the tire go forward and complete a revolution. I found this to be the case on both front tires. So, the decision is to change the front 2 rotors and pads.

So, now comes the exciting part. I'm definitely not going to Nissan again, so I've researched the following and would like to know if anyone has strong like/dislike for them:

Complete front rotors + pads kit:
http://brakeperformance.com/brake-rotor ... oating.php

OR

Rotors:
http://www.tirerack.com/brakes/brakes.j ... toModClar=
Pads:
http://www.tirerack.com/brakes/brakes.j ... toModClar=

Any other potential leads would be greatly appreciated.

Thanks!

[NolimitZ32]

oooh upgraydd (with two Ds for a double dose of his pimpin).

STOPTECH all day.

also have a gander at these: http://www.z1motorsports.com/product_in ... cts_id=138

[gugga4u]

oooh upgraydd (with two Ds for a double dose of his pimpin).

STOPTECH all day.

also have a gander at these: http://www.z1motorsports.com/product_in ... cts_id=138

I have a few friends using STOPTECH, and they've all been happy. So, I'm leaning towards STOPTECHs.

I could not find any customer reviews on the ones from Z1motorsports. Anyone using them? Any customer reviews?

Thanks!

[DCaff300ZX]

I agree with NoLimit, I'd go Stoptech any day, and am surprised at the prices there- high but not THAT bad compared to OEM.
If you can afford them do the Stoptech for sure, never heard a bad thing about them anywhere.

[NolimitZ32]

The Z1s are supposedly Brembos, thats not to say they aren't but I would call them if you are interested and if the coffers are running dry. Otherwise STOPTECH all day.

[gugga4u]

I found this article to be the final nail in the coffin:

http://www.twinturbo.net/ttnetfaq/FAQpa ... rping.html

This article has ALL the signs that were with my car for the past year w.r.t breaking/shimmying/shaking/etc.

I had my local mechanic install the following today (4/27/15) with instructions from the above article, and will update this post after a month to see how they rotors/pads are holding up:

Pads: Hawk HPS Street brake pads (Performance Street)
Rotors: Centric High Carbon Plain 125 Series Rotor (Premium, Performance Street, Autocross/Track)

Thanks for everyone's help!

[DCaff300ZX]

I found this article to be the final nail in the coffin:

http://www.twinturbo.net/ttnetfaq/FAQpa ... rping.html

This article has ALL the signs that were with my car for the past year w.r.t breaking/shimmying/shaking/etc.

I had my local mechanic install the following today (4/27/15) with instructions from the above article, and will update this post after a month to see how they rotors/pads are holding up:

Pads: Hawk HPS Street brake pads (Performance Street)
Rotors: Centric High Carbon Plain 125 Series Rotor (Premium, Performance Street, Autocross/Track)

Thanks for everyone's help!

Awesome info, I learned something there and appreciate it!
Hopefully this gets you back onto the road with problem solved completely, and I myself will be sure to run mine through the same process- I am currently experiencing different brake issues myself and have never gotten the full performance from my GTR brakes I added and I feel this may well be a large part of my issue as well- the uneven brake pad/rotor wear is the tip of the day for me, and hopefully others who have nagging brake issues.
This type of problem (runout) affects more than just a shimmy as it is an issue of the brake system being out of spec, and working harder in order to meet the need.