poormxdad

Gentlemen,

I have a shake through the steering wheel that I can't isolate. On the way to VIR, I had a little vibration that I blamed on my Conti ECS and my inability to properly balance them myself. The vibration was worse when I swapped in my track front pads and Federal 595s. I swapped left side tires front to back. No change. I swapped right side tires front to back. No change. Then, I had all four wheels balanced nearby. No change, I swapped in my spare brake disc on the passenger side. No change. I reversed that and swapped the spare disc onto the driver's side. No change. The wheel bearings are fine, confirmed by two other folks. Tie rod ends are fine. Front bushings are Mazdaspeed replaced about a year ago and have low miles. Nothing feels loose with one wheel off the ground, but I know I have more work to do when I get her home.

What should I look for?

Thanks,

technicalninja

You left out the description of what is happening when you feel the vibrations. What speed? Will acceleration or braking change it?
Do you feel it in corners or only going straight?
Can you alter the vibration in any way?

boileralum

iTrader: (8)

Check ball joints for play

poormxdad

Sorry. You're right. Been a long day...
It's worse in a right turn, but it's basically there at all speeds. It goes away during braking. One of the other guys that drove the car said it "felt loose".

technicalninja

Right turn loads left front suspension.
Disappears during braking sort of rules out brake stuff...
At all speeds rules out tire balance but it doesn't rule out bent wheel. Gone during braking sort of rules out bent wheel. Always check wheels for run out.
I see wheels bent on inside bead more than outside bead
Look to left front suspension for loose crap. ball joints need to be checked at normal ride height. If the suspension is unloaded (up in air) the worn spot in the BJ will not be evident.
Have someone jounce and shake the crap out of the car while you're underneath (you need to be SKINNY) and see if you can see it. They need to shake both the car and the wheels while checking.
Don't use your wife, get a big brawny guy to shake it
If you're running toe out in the front (common on race cars) it will make it worse. Adjust to toe in and see if it changes it...

technicalninja

Swapping wheels rules out wheels. Sticker tires will make a suspension looseness more evident.
Check tightness of all fasteners in front suspension.

poormxdad

I swapped to my travel/wet weather tires, but didn't go back out on track. Uneventful trip home. I felt a little vibration come on about 63 mph. I had a chance to pass a couple of people. The shake starts at about 80. I put her up on jack stands and used a floor jack to move the control arms up and down. I watched from every angle possible and could not see anything loose anywhere, including at the inner bushings. I'll check tightness of all fasteners when I get home from work.

Thanks,

technicalninja

I've had trouble getting the control arms to "normal ride height" when on jack stands. By the time you get close it picks up the car off of the closest jack stand and shaking it hard is not a good idea.
An alignment bed has centerless rotation pads (think lazy susan) which make joint inspection a breeze. I've wanted to make a pair of these using air pressure (like an air hockey table) for years.
They are extremely helpful when checking suspension play. You can also install sand bags or extra humans in the car to re-create actual running height.
Only way to check the suspension through all ranges of travel on stands is to remove the shock/spring assembly.
This works fine but is labor intensive.

drakec9

have you checked the steering rack bolts to make sure theyre tight and steering rack bushings to make sure they arent at the end of their life?

bAsEDnancy

+1 to the rack bushings. had a similar issue on my previous vehicle

poormxdad

I checked all the suspension bolts and steering rack bolts. I also swapped out the right front hub even though it seemed fine. It was about a year old, although with fewer events than normal due to C19, but the other one of the pair I purchased had failed already.

Unfortunately, I only had a few days to get ready for my next event, so I didn't have time to do just one thing, put her back together, and test drive. However, she seemed fine after everything I did. The shake was gone. I had a weekend on Summit Point Main, and no issues. When I got home, I put her up on stands to do my usual post-event inspection, and to look for a new rattle that turned out to be the heat shield on the cat. I rotated tires and took her out for a drive and the shake was back. Turns out the right front tire needed balancing. I balanced all of them and went for a ride. The shake was gone.

It seems I have something that magnifies the effect of an out-of-balance tire. I've had tires out of balance before and the shake was never this bad. Does that still point to the steering rack bushings?

Thanks,

drakec9

[QUOTE=poormxdad]

It seems I have something that magnifies the effect of an out-of-balance tire. I've had tires out of balance before and the shake was never this bad. Does that still point to the steering rack bushings?


I have experienced a similar issue with my miata after flying off track and bending a front wheel. The steering wheel would shake/vibrate violently anywhere above 50mph. With 2 brand new wheels and tires the shake disappeared. I later performed a bolt check with the new shoes up front and found the front 2 steering rack bolts loose. I have reason to believe that worn bushings would create a similar issue, like with your car.
Poly Steering rack bushings are $50ish from flyin miata. In my opinion, they are cheap enough to buy as insurance.

x_25

We had that magnification issue on my mom's minivan. It turned out to be an inner tie rod end. I would be something is loose in the steering.

poormxdad

I decided to check price and availability of the OEM passenger side steering rack bushing. The young man on the other end of the phone said "Hmmmmmmmmmmmm, it'll take about a week to get. There's only one in the country and it's in Canada".

poormxdad

I cannot get replacement steering rack bushings before my next event, but I ordered the Prothane package. The OEM parts have actually been retired--they're not just in Canada.

I pulled off the steering rack clamp on the passenger side. The bushing is still supple and there's no visible deterioration. Same with the bushings on the driver's side. I checked toe up front and rotated the tie rods in and out several turns. Nothing seemed out of the ordinary. I depowered that rack seven or so years ago and installed new tie rods. Is there an expiration date on tie rods for the track?

Thanks,

technicalninja

When you de-powered the rack did you do something to the pinion?
The usual trick is to weld or pin the 2 "sides" of the pinion together.
If you did not this is what I would look at next.

Outer TREs are in-expensive and easy to change but I would think that enough play to cause a vibration would be enough play to see and feel during inspection.

poormxdad

I took the two front tires/wheels to have them checked on a road force balancer. The right one was off by 1.5 ounces. With the engine undertray off, I found the right side tie rod did have some slight play at the ball end. Awaiting parts...

Thanks for all the inputs.

poormxdad

Dammit. Dammit. Dammit. ****. ****. ****.

I replaced the passenger side tie rod and tightened everything up. The play was still there. It's in the steering rack shaft itself. I could feel it on the passenger side, but not on the driver's side. Also, it's not the rack mount bushing. Is there anything I can do short of depowering and installing another rack before my next event?

technicalninja

Might look to inner TRE. It's under the boot and changeable.

poormxdad

Not accurate. The "tie rod" includes the inner tie rod end--the ball joint part. There's no separate inner tie rod end. I replaced the tie rod, since that's what I believed was the problem. However, the new tie rod (with the new joint) had the same movement. With the boot off and the wheel turned to the right, I could see the steering rack shaft move up and down slightly. That wasn't apparent when everything was covered up. I thought it was the tie rod. I depowered that rack probably seven years ago.