S13 Steering Vibration/ Shimmy

[Agentnumber2]

I've searched and read almost all the threads on this and it usually ended up being either 1) bad balance 2) steering rack tension nut 3) or the usual, the thread is abandoned.

Symptoms:
Steering wheel vibrates at and over 60mph
Consistent vibration at and over 60mph
Happens over smooth roads

Here's what I have done (vibration occurred before these were replaced):
Nismo power brace
SPL tension rods
S14 inner and outer tie rods
New steering rack (as of yesterday)
-So I guess adjusting screw/nut fix doesn't apply to me?
Wheels balanced
Alignment (as of yesterday)
Tires are two months old (Federal 595 Evo)
Poly steering rack bushings
Swapped the rear wheels with newer tires to the front vice versa

What I suspect:
Driver wheel has a slight bend but still zeroes out when balanced
https://40.media.tumblr.com/5ad3626b544d09e4b0f890600f6fdc4e/tumblr_nlwgslSQ141qd2gt4o1_1280.jpg
Front tires (I know for sure) are oblong shaped but my rears are not and I swapped them and the vibration still continued.
Tires have feathering (very very minor)
Bad ball joint/ LCA bushing

Before I spend a couple hundred here and there I really want to isolate the issue with your help. Any input or advice will go a long way. I am not ready to give up yet!

[bcl_s14]

yeah I'd love to find out what's going on too. A friend of mine is having similar issues.

[CrimsonRockett]

You really don't need to spend a ton of money to solve this.

You mentioned bad ball joints. Those don't cost much to replace.

Also, ever take a look at your steering rack bushing? That piece is 20+ years old at this point. There is a solid aluminum replacement available. Highly recommend replacing that.

You've replaced just about everything else. So, you've narrowed it down significantly.

http://www.frsport.com/images/upload/03a_Lower_column_removed.jpg

http://www.forcedfabllc.com/assets/images/products/SteeringColum_AlumBushing__54708.1330228957.1280.1 280__15205.jpg

[Agentnumber2]

Ball joints are next go in! I have new FLCA and I'm going to swap the bushings to the poly ones I have.

I'm sure that the steering column bushing is no good either. I've read a few DIY installs and I must say the job looks a little intimidating. However, I'll order the part as soon as I can. What is the benefit of going with an aluminum one versus a poly one (if they offer it, haven't searched)?

Thank you very much for your input. I shall update everybody with results as soon as I get time.
You really don't need to spend a ton of money to solve this.

You mentioned bad ball joints. Those don't cost much to replace.

Also, ever take a look at your steering rack bushing? That piece is 20+ years old at this point. There is a solid aluminum replacement available. Highly recommend replacing that.

You've replaced just about everything else. So, you've narrowed it down significantly.

http://www.frsport.com/images/upload/03a_Lower_column_removed.jpg

http://www.forcedfabllc.com/assets/images/products/SteeringColum_AlumBushing__54708.1330228957.1280.1 280__15205.jpg

[Agentnumber2]

Update: new LCA's with new balljoints and bushings have been installed. It soaked up about 60% of the vibration but still feel it at freeway speeds.

I also noticed that the coilover nuts were loose on the shock towers. I tightened those down as well.

I'm currently on the hunt to find a friend with spares so I can run a different rims and tires to see if that's it.

Next on list: brake pads/ rotors, bearings, steering shaft bushing.