Suspension and Chassis Questions about your suspension? Need chassis advice?

Death Wobble?

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Old 12-02-2019, 12:16 PM
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Car: 91 Firebird
Engine: 5.0L
Transmission: WC 5 speed manual
Death Wobble?

Started out a few months a slight wobble felt in the front end, no steering column shake or vibration at all, steering is very tight still (125k miles).
Replaced rotors and drums (not calipers /pistons) and had a caliper stick a few times. The wobble started out when exiting an off ramp and not sure if the wobble is triggered when braking because it seems to happen after the initial braking, after releasing the brake pedal. And, braking does not stop the wobbling although when it happens I immediately brake and coast in order to slow car down and the wobbling will decrease / end.

It is no different then a Jeep Cherokee death wobble, only a lot less severe! The Jeep was a 8.0 magnitude, my bird feels like a 2.0 .... to 4.5.
Now it just began happening right after / during acceleration. Gotta be fixed. My birds' condition is very very good. This wobblin' will beat the sheesh out of the car!

I am doubting a frame crack near steering box. The only visual stretching i'm aware of and just recently appeared are corner pillars / quarter panel (cracking in paint).

T5 is tight although it began the whine in colder weather. The type of whine that goes away when you touch the clutch. Changed fluid, stopped whining, 2 weeks later, whining just a little (cold).

While on lift during fluid change we visually inspected suspension and tie rod / bushings. Bushings at ends are dry and cracked. The long bar that runs from one side to the other underneath the car, if I remember, seemed a little weak.

My rim / tire size is 22 inch - replica IROC rims. 22/35/165 rear, fronts not as wide. Not sure if a pot hole is cause for the wobble. I did hit a few big ones that really depressed me for a day and I actually hit a deep one on the freeway but no symptoms followed. * I did noticed after hitting one at 30 mph, I felt the body wobble slightly. * Other than that, alignment seems fine, no noises, is still smooth at every speed.

I will start by inspecting for bent rims. Also, wheel bearings were also replaced when I did the brakes - (came w/ rotors). I do have one missing lug nut on a rear wheel - fixing now. I did feel / heard slight play as I pushed and pulled on THAT wheel (may be normal)... Other side, no play at all.

Any psychics, here?



Last edited by okay; 12-02-2019 at 12:23 PM.
Old 12-02-2019, 02:38 PM
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Car: 1989 Firebird GTA
Engine: Motown Aluminum 427
Transmission: TH400/GVO
Axle/Gears: Dana 44 IRS 3.75:1
Re: Death Wobble?

make sure those castle nuts setting the rotor/bearings on the spindle are set up correctly. many things can do this, but within the context of your recent repairs, and in the absence of this happening before, you need to check the things you changed first. could be as simple as loose lugnuts.
Old 12-05-2019, 10:10 AM
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Re: Death Wobble?

yea if linkage and lug nuts check out but willing to bet it the wheel bearings any little play and you will feel front end wobble had front wheel bearing go bad on
a truck I had similar spindle bearing setup
but quick way to check is lift front up and wiggle the tire on top of tire and sides and see where the play is coming from
Torque specs are 80-90 Ft-Lbs.
I've also just tighten it till its tight and then back of a little just by feel usually its like a 1/4 of a turn what I do majority of time
you shouldn't feel any play

those big heavy wheels and also bad struts which are notorious for going bad will just make matters worse as well due to the extra
rotational weight moving around
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Old 12-08-2019, 07:36 AM
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Re: Death Wobble?

What the hell is a 22/35/165 tire size??? How big those tires actually are might have some relevance to the problem. What suspension modifications were done to put them on there?

The Jeep and more specifically Dodge truck solid axle front suspension "death wobble" is something specific to that suspension design, and it should be JUST about impossible to duplicate with a 3rd gen front suspension. For those of you that are not familiar with it those suspensions (my Cummins dodge had some parts replaced under recall for this), in some situations might end up getting in an oscillation where it starts yanking the steering back and forth and it actually keeps getting worse till you get the vehicle stopped. Anything of that magnitude on a 3rd gen will 1- stop when you try to slow down and 2- would require some HORRIBLY worn out parts to the point that even a half retarded blind "mechanic" should be able to find them next to instantly.

So assuming that this car isn't beat to hell with a wiped out suspension (you seem to indicate it's in good shape), what exactly is it doing and under what conditions? I'll start with that there is no way in hell that anything on these cars was designed for the weight and rotational inertia of a 22" rim so if anything is worn out it needs to be replaced first.
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Old 12-08-2019, 11:01 AM
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Re: Death Wobble?

The caliper is sticking after replacing the rotors? If so you’ve probably got a warped rotor. And did you replace the brake line as well? I would have, they’re cheap.
Old 12-08-2019, 02:59 PM
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Re: Death Wobble?

Sounds like a "stuck caliper".

Thing is, calipers HARDLY EVER "stick" in this system. More likely, it's the rubber hose for one of them, which MAKES the caliper "stick". The way those fail is, they rust inside, until the already small hole in the fitting, becomes SO small that once the fluid is pushed in by the pedal, it can't get back out.

You don't mention any other strange brake behavior, but if there is any, that points even more strongly to the rubber hoses. Particularly, if when you first hit the brakes (esp in a "panic" situation) the car dives toward one side, then when you let back up off of them, it dives a bit to the other side. Or, if you have trouble bleeding one side, such that very little fluid comes out. If so, then the hose on the side it dives away from initially and/or toward as you release the pedal, or the one that doesn't bleed freely, is the bad one. Not that it matters which "one" is bad; both of them, and the rear(s) as well, have been submerged in the EXACT same fluid under the EXACT same conditions for the EXACT same length of time, and it's only a matter of time, and very little of that, until the next one fails the EXACT same way. They're CHEEEEEEEEEEP; when in doubt, swap em out. For that matter, calipers are less than $15 apiece; makes NO SENSE WHATSOEVER to even TOUCH the brakes and not replace those. Just do it. Bust out the old parts cannon and shoot calipers and hoses at the car.
Old 12-09-2019, 10:33 AM
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Re: Death Wobble?

This just my opinion on stuck caliper is that I don't think it will generate a wobble and would
create more of a dragging or pulling sensation OP example and explanation isn't a accurate
as stated above due to suspension design but any type of wobble sensation to me would be
ball joint, tie rods and steering components and wheel bearing vs a sticking caliper and symptom
is only amplified due to his tire and wheel setup
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