85 gs with the gsl rear end.
So my steering wheel shakes really bad mostly going straight between 35 and 45mph. I turn a little in either direction and it goes away for the mostt part. Any other speeds it's fine. When i bought the car all the tie rod ends were loose (the tie rods were fine, it was the actual bolts that were loose) but there was no vibration, just really loose steering. Now that i tightened then up, replaced the idler arm Bushs, and tightened up the steering box i have the vibration. I got an alignment the other day and they told me the tie rod adjuster it's bent and the lower control arm "appears to be bent". Would that cause the shake? Either way they're gonna get replaced but i want to get this issue figured out first

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Yes, it would. The first thing to do would be identify & replace any bent/broken pieces.

You could post a "parts wanted" thread in the proper section of the forum, and with luck
find someone parting out a car nearby.



.

 

Certainly getting those linkage and suspension parts fixed and an alignment are in order. You may also have a problem with worn and unbalanced tires.

 

Fix the bent parts because they for sure aren't helping.

Other possible causes:
Worn/unbalanced tires as Ray said. Possibly coupled with a failing strut.
Loose /worn wheel bearing
Bent rim
Bad ball joint

The alignment guy should have checked the ball joints and bearings before aligning it (shops use alignments to find other potential repairs); they would not necessarily sopt a balance or bent-rim problem.

 

thanks for the advice. i know i do have a some worn tires. both front tires have some pretty good + camber wear. i was gonna try switching them to the back and seeing if that helps. dont know about the balance though. ive been meaning to check the bearings but dont have a spring scale, and not quite sure where to find one. the local harbor freight doesnt have them. will one for hunting/fishing work? ball joints are good. as far as a bent rim, wouldnt that cause the vibration at all speeds? not just 35-45 only going straight?

 

Update:
I switched the tires to the back and its way better. I can still feel it some from the back but not nearly as much as the front. The wheel is still shaking a little though. Hopefully replacing the bent parts will fix it. Going to pick them up Monday (thank God for rx7/miata only shops, don't know what id do with out this guy!)
As far as the wheels I'm gonna go have the balanced checked and replace those worn tires as soon as i can afford it

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Out-of-round/out-of-balance conditions on a wheel/tire can be speed sensitive because at certain speeds, the tire RPM can hit a harmonic with the suspension. Same reason driveshaft/u-joint probs can be speed-sensitive.

Far as spring scales go, I found one on Amazon (for science class use) a while back; wasn't expensive either. Even calibrated in kilos.

But you can check bearings by attaching a known weight to a lug bolt, hanging vertically from the bolt at 3'oclock or 9'oclock position; I used dive weights before I ever found a spring scale. Gravity works just the same as spring tension for linear force.

 

Ok that makes sense, let's hope it's just the balance or tire, don't know where i would find a matching wheel...

And i actually just found a cool little digital spring scale at harbour freight for$15, so I'm gonna go pick that up

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Seized brake caliper will give intermittent vibration too.

 

mine was doing it but when I spec'd the bearings it went away for the most part

 

What about a caliper that's seized so that it's not touching the pads at all?

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Well, if it's not touching the pads there's no way for it to cause a shimmy directly (uneven braking would cause a serious pull toward the side still working, but only with brakes applied)...

But if you've got a caliper that's not working, you should fix it before the next time you put the key in the car!

 

I think you've just crossed that line where you need to park the car, put it up on jacks and trouble shoot the entire suspension and brake system yourself.

Get a Haines manual, find out what parts you need and put in a Rock Auto order for half the cost of your "rx7/miata only" shops. Post up any questions you have on this thread, with lots of photos. You'll get answers: We've been there, done that. Then do it yourself.

In the end you'll spend less money than a single visit to a mechanic (especially the ones who charge extra because it is a rotary engine), your brakes will work the way their supposed to and the suspension and steering will be tight. And you'll know your car a whole lot better.

I can even show you how to do your front end alignment in your driveway with a piece of string. For free.

Then use the money you saved to buy a new set of tires and the knowledge you've gained to save more money.

 

tire balancing is like $15 so get that out of the way, next jack up each corner of the car and do a 4 point push/pull test on the tire. there should be marginal play of a few mm at the top and bottom edge of the tire(more than that means the bearings are failing or need to be repacked and adjusted), horizontal play can easily be associated to worn steering components as there are many linkages on the FB that wear.

 

Well that's the thing though. When i brake it doesn't pull but when i have it up in the air i can wiggle the caliper like you could when you change the brakes before hitting the pedal for the first time. It's kinda like when i let off the brakes the piston retracts all the way back in it something. Never seven any thing like that before. So I'm guessing it's not seized since it doesn't pull but something is definitely going on. It stops just fine though other than the pads in the other side being about gone and the matter cylinder starting to go

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if the pad is loose on the rotor than you have air in that particular line and it isnt braking for you

 

That's what i thought too but i bled it and no air came out

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