2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

90 S5 NA GTU FC, lowered car causing steering shake at 65mph speed?

Thread Tools
 
Search this Thread
 
Old Aug 25, 2015 | 04:48 PM
  #1  
ncds_fc's Avatar
Thread Starter
Rotary Otaku
Tenured Member 10 Years
 
Joined: Aug 2005
Posts: 34
Likes: 0
From: SF Bay Area
CA 90 S5 NA GTU FC, lowered car causing steering shake at 65mph speed?

Previous Owner of FC had it lowered. I did not see any coilovers (neither adjustable or non-adjustable).

It was unbearable to drive the car past 65mph, but keeping it at 65mph was okay (except on long drives over an hour on the freeway. I replaced the motor mounts as one of them was torn when I reinstalled the rebuilt motor.

I looked at the Hayne's Manual, thought of getting the tires rebalanced and getting an alignment done. I notice it doesn't shake like crazy, or becomes smooth on slight turns on the road, just not on straight-aways.

Am I right to assume it's tire balance and alignment, or should I also take a look at the steering system? PO went cheap on mods before I bought it, from what it seems.
Reply
Old Aug 25, 2015 | 08:33 PM
  #2  
diabolical1's Avatar
Moderator
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (3)
 
Joined: Feb 2002
Posts: 10,998
Likes: 349
From: FL
start with checking the tires themselves and the alignment. if those are in order, then start looking front end components (tie rod ends, bushings, etc.)


also, i'm moving this to the Gen II forum since you're not exactly new here.
Reply
Old Aug 26, 2015 | 03:47 AM
  #3  
ncds_fc's Avatar
Thread Starter
Rotary Otaku
Tenured Member 10 Years
 
Joined: Aug 2005
Posts: 34
Likes: 0
From: SF Bay Area
Thanks, diabolical1. Wasn't sure where to post since it has felt like forever since I was really active here. Been lurking since I got my first FC and happy to be active again with my current "running" FC.
Reply
Old Aug 26, 2015 | 04:49 AM
  #4  
barkz's Avatar
Rotary Enthusiast
Tenured Member 05 Years
iTrader: (1)
 
Joined: Sep 2011
Posts: 1,261
Likes: 1
From: New Hampsha
Only shake in steering wheel or in your butt too? Might just need an alignment. And balance the wheels while you're at it
Reply
Old Aug 26, 2015 | 10:15 AM
  #5  
Rob XX 7's Avatar
FC guy
Tenured Member 20 Years
iTrader: (8)
 
Joined: Oct 2002
Posts: 8,713
Likes: 17
From: Long Island, New York
check simple things first, jack up the car and pull the wheel back and forth
check for wheel spacers that are not hubcentric
Reply
Old Aug 26, 2015 | 11:18 AM
  #6  
RotaryEvolution's Avatar
Sharp Claws
Tenured Member 15 Years
iTrader: (30)
 
Joined: Oct 2003
Posts: 5,107
Likes: 50
From: Central Florida
a shake in the wheel is usually a bent wheel or a ripped cord in a front tire, out of balance tires will certainly give a vibration but they will not cause a shimmy in the wheel. the alignment being out from lowering the car will make the issue more pronounced.

rotate the tires to the rear and i bet the shimmy will go away but you likely will still have some vibration and/or sway in the *** end.
Reply
Old Aug 26, 2015 | 11:24 AM
  #7  
jjwalker's Avatar
MECP Certified Installer
Tenured Member 05 Years
 
Joined: Feb 2009
Posts: 3,176
Likes: 3
From: Mesquite, TX-DFW
Originally Posted by Lyger
a shake in the wheel is usually a bent wheel or a ripped cord in a front tire, out of balance tires will certainly give a vibration but they will not cause a shimmy in the wheel. the alignment being out from lowering the car will make the issue more pronounced.

rotate the tires to the rear and i bet the shimmy will go away but you likely will still have some vibration and/or sway in the *** end.
LOL, the reason I am laughing is because just a week ago, I was describing the work needed to do what the customer wanted and said " I got to run this to the *** end of the truck and stay away from the springs". He laughed his *** of because he never heard it before.

I thought everyone knew what the *** end of a vehicle was, especially in the south.
Reply
Old Aug 27, 2015 | 01:41 AM
  #8  
ncds_fc's Avatar
Thread Starter
Rotary Otaku
Tenured Member 10 Years
 
Joined: Aug 2005
Posts: 34
Likes: 0
From: SF Bay Area
Originally Posted by barkz
Only shake in steering wheel or in your butt too? Might just need an alignment. And balance the wheels while you're at it
Shaking in the steering wheel only. I'm hoping that it's just tire balance and needing an alignment. Planning to buy BBS mesh wheels and tires off another FC owner soon, since my current tires have cracked and lost outside tread it seems and the lug nuts are a PITA if it wasn't for the included socket from the PO.

Thanks, everyone. I had ideas of what could be causing the shaking but just wanted to confirm them, as well as getting more ideas of what to inspect.

And I realized my FC has a Salvage Title after I got Title in the mail... =( Time to check Carfax.
Reply
Old Aug 27, 2015 | 07:09 AM
  #9  
misterstyx69's Avatar
Retired Moderator, RIP
Tenured Member: 20 Years
iTrader: (142)
 
Joined: Sep 2005
Posts: 25,581
Likes: 136
From: Smiths Falls.(near Ottawa!.Mapquest IT!)
Check your ball joints.
I couldn't go over 50mph in my vert..it would hop all over the place.Even though I had jacked the car up and checked the front I didn't find it until I pretty well disassembled everything.
I stuck a crow bar in between the spindle assembly and the lower arm and Finally found out the damn joint was toast.
Reply
Old Aug 27, 2015 | 07:54 AM
  #10  
rx7racerca's Avatar
Rotary Freak
Tenured Member: 20 Years
Liked
iTrader: (1)
 
Joined: Jul 2004
Posts: 1,725
Likes: 8
From: Lake Country, BC, Canada
I agree, you are likely looking at tire damage, or worn or misaligned suspension. So anything related to the tires and suspension. Helpful, no?

That said - was the car aligned after lowering? It seems to me that lowering the FC front produces more toe in - which not only is going to kill your tires, it might account for your shimmy, as the front tires effectively are fighting each other, and variations in road surface (or camber side-to-side) give the advantage to one, then the other.
Reply
Old Aug 27, 2015 | 08:27 AM
  #11  
Rob XX 7's Avatar
FC guy
Tenured Member 20 Years
iTrader: (8)
 
Joined: Oct 2002
Posts: 8,713
Likes: 17
From: Long Island, New York
i think the first thing is to get some better tires that arent missing treads lol
maybe you will also find he has the wrong style lug nuts and they arent seating properly either
Reply
Old Aug 27, 2015 | 08:56 AM
  #12  
misterstyx69's Avatar
Retired Moderator, RIP
Tenured Member: 20 Years
iTrader: (142)
 
Joined: Sep 2005
Posts: 25,581
Likes: 136
From: Smiths Falls.(near Ottawa!.Mapquest IT!)
OH..you will find that the S5 Ball joints are part of the lower control arm and the WHOLE arm will need to be changed IF the ball joint is toast.
Guys fix this easily by changing the whole lower control arm to an S4 Series assembly which has replaceable ball joints( they bolt in).
One thing about the s5 was a lot of stupid plastic parts,like the sway bar links.They suck!
Reply
Old Aug 27, 2015 | 08:58 AM
  #13  
Rob XX 7's Avatar
FC guy
Tenured Member 20 Years
iTrader: (8)
 
Joined: Oct 2002
Posts: 8,713
Likes: 17
From: Long Island, New York
hey my car doesnt start give me some ideas.....by the way I have no gas in the tank
Reply
Old Aug 27, 2015 | 09:03 AM
  #14  
misterstyx69's Avatar
Retired Moderator, RIP
Tenured Member: 20 Years
iTrader: (142)
 
Joined: Sep 2005
Posts: 25,581
Likes: 136
From: Smiths Falls.(near Ottawa!.Mapquest IT!)
Originally Posted by Rob XX 7
hey my car doesnt start give me some ideas.....by the way I have no gas in the tank
eat 2 pounds of Chili..something will get gas and start moving!
Reply
Old Aug 28, 2015 | 02:03 AM
  #15  
ncds_fc's Avatar
Thread Starter
Rotary Otaku
Tenured Member 10 Years
 
Joined: Aug 2005
Posts: 34
Likes: 0
From: SF Bay Area
Just replaced my clutch master and slave cylinders, leaked like crazy close by. I inspected the tires, and ya'll were right. One of the tires is already showing the cords on the inside of the tread on the front driver-side tire. Looks like the tires were rotated before I bought it from the looks of it on the other tires, but the tread is going as well.

I didn't think of looking at the ball joints, I'll give that shot.
Reply
Old Aug 28, 2015 | 10:14 AM
  #16  
SecondGenPat's Avatar
In search of turbo...
Tenured Member: 15 Years
 
Joined: Jul 2008
Posts: 102
Likes: 0
From: Indiana
I just went through this issue on my normal suspension FC (single piston calipers.)
Here I found I had a front caliper seized causing it to drag on the rotor and heat soak when I finally parked it. this allowed the pad to transfer more material to the rotor as it cooled, causing a high spot which would, in effect, cause the brake to grab that spot every revolution to show up as a steering wheel shimmy above 70mph for me.
My fix was a rebulit caliper and new rotor as the old one was trashed.
Reply
Old Aug 28, 2015 | 10:52 AM
  #17  
DeaconBlue's Avatar
Living on the North Coast
iTrader: (31)
 
Joined: Mar 2009
Posts: 600
Likes: 7
From: Avon Lake
If the car is slammed to the ground, you may also have a bump steer issue.
Reply
Old Sep 10, 2015 | 03:52 AM
  #18  
ncds_fc's Avatar
Thread Starter
Rotary Otaku
Tenured Member 10 Years
 
Joined: Aug 2005
Posts: 34
Likes: 0
From: SF Bay Area
New tires solved the problem. Glad it didn't require a major fix. Just in time as well, since an inspection revealed I was missing nuts for the struts, struts were leaking, and cracked tire walls on the rear tires (it had been sitting in the sun for over 2 years).
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
82streetracer
Haltech Forum
11
Mar 11, 2019 05:34 PM




All times are GMT -5. The time now is 08:48 PM.