mysterious death wobble

[chris989]

Hello all,
1989 v2500, 2 inch lift, 37 falkens

A few months ago i experienced my first ever wobble in this truck. Other than a tire rotation and new steering box nothing has changed. It wasn't horrific but definitely a shock since for more than a decade and many many miles it has never done it.

I've been under the truck all morning and nothing looks a miss.. all tight, no movement in and joint, bushing or bearing. (that i can detect)

If you ever had this and figured out the culprit, please share.

Thank you,
Chris

[GM72K10]

My death wobble was caused by a partially restricted front brake hose. Put on new front brake hoses and problem went away! Took quite a while to figure that out.

[dagnabbitt]

It's scary. On my truck it was the tires, severe cupping. Always happened when tires were cold at 45 mph. With a lift and 37s I would take a look.

Its intermittent because the tires are essentially out of round, and the death wobble only occurs when they all hit the same flat spot at the same time.

[raggedjim]

Originally Posted by GM72K10

My death wobble was caused by a partially restricted front brake hose. Put on new front brake hoses and problem went away! Took quite a while to figure that out.

I've had this on Chevrolet trucks before. On mine it felt more like a hard shuddering.

Originally Posted by dagnabbitt

It's scary. On my truck it was the tires, severe cupping. Always happened when tires were cold at 45 mph. With a lift and 37s I would take a look.

Its intermittent because the tires are essentially out of round, and the death wobble only occurs when they all hit the same flat spot at the same time.

Had this on my Jeep, new tires cured it.

[Willie Makeit]

Worn ball joints have been known to cause this as well.

[old Rusty C10]

do you have the proper or a new steering damper on it ( the shock crossways on the front end) i had a truck that that piece was shot and caused a wobble after the sloppy steering box was replaced

[Stepside Jim]

Mine was ball joints...

[Dead Parrot]

Happened after tire rotation? Suspect bad or out of balance front tires. Especially if it was a front to back swap.

On my 84 K30, replacing the bushings between the axle and steering fixed it.

[57taskforce]

Originally Posted by Dead Parrot

Happened after tire rotation? Suspect bad or out of balance front tires. Especially if it was a front to back swap.

On my 84 K30, replacing the bushings between the axle and steering fixed it.

I assume you are talking about the king pin bushing on the Dana 60? The 10 bolt in his 3/4 ton won’t have those. I’d look into the tires more as well. I’ve even had a late model 3/4 ton IFS GMC that got death wobble because the tires were shot. That’s not supposed to be able to happen on IFS stuff. If it came from out of the blue I’d start with the things most recently changed first. When you add the bigger tires any issues with them just get amplified compared to stock size tires. Toe will cause it too if not set right, with 37’s I’d be shooting for closer to 1/4 toe in if it was me.

[cadillac_al]

2" isn't much lift to cause a problem. I have had my K20 for 30 years and had the 2" lift and 35's for 20 years. The only time I had death wobble is when I had too much mud in the wheels. With clean wheels it will roll nice and smooth at 70-80 mph. On my Jeep Grand Cherokee the only time I had death wobble was with old flat spot tires. I always blame the tires first

[chris989]

Thanks for all the replies,

I spent a few hours under the truck the other day and everything looks tight and right.

The tires have 70% tread left and show no signs of uneven wear. I spoke to Laura's steering gear company wondering if possibly the tire was giving a negative feedback through the steering gear via the torsion bar and they'd never heard of that.

I had a steering gear with a 160 torsion bar and the tires would definitely feedback through the gearbox giving it a odd sensation.


This morning it happened again going maybe 20 miles an hour in a neighborhood after hitting a bump. I guess I'm going to put it back in the shop and just pull everything apart read grease reinspect.

[Getter-Done]

Have you checked for cracks around the steering box?

[Dead Parrot]

Originally Posted by 57taskforce

I assume you are talking about the king pin bushing on the Dana 60? The 10 bolt in his 3/4 ton won’t have those. ....

Yes. Couldn't remember what they were called when I responded. Replaced them several years ago.

But his start after a bump symptoms are very similar to what mine was doing. If there is anything that serves a similar function on his, might start there.

Worn shocks? Frame good around the steering box?

[67swb72klb]

I would be looking at the toe too if all your parts check out good..

[Dashman]

I had it happen on my '81K20 after I had replaced EVERYTHING. Not like I was chasing the issue, everything was worn out. Axle U-joints, ball joints, steering gear box, steering rag joint, tie rod links, steering stabilizer, brake lines, leaf spring bushings (as part of a lift kit), and tires. The two last things that stopped it were the drag link ends, and shocks. I believe that shocks play a major role in dampening the vertical wheel movement that would prevent the issue. It's doing it on my current '72K10 project because I don't have shocks on it.

[chris989]

Update,,

Had the tires balanced and rotated today and pulling out of the parking lot i got the wobble at ~15 mph..

I am under the truck now and everything is tight.. THe tie rods ends do rotate easier than when new.

I will pull the shocks next,,, I run quad nitrogens.

I will update when i figure it out..

Chris

[cadillac_al]

Did you check for a crack by the steering box? I have never had one but people say it is common. I would think if you could have somebody move the steering wheel side to side while you look at it it should not be moving.

[chris989]

Originally Posted by cadillac_al

Did you check for a crack by the steering box? I have never had one but people say it is common. I would think if you could have somebody move the steering wheel side to side while you look at it it should not be moving.

I checked,, all good. THe truck is on stands with tires off. with the steering locked,, there is zero movement in the hubs, links, etc. The is a little movement in the lash of the steering gear..

The shocks show no sign of fatigue or leaking... I will pull them tomorrow anyway..

Chris

[KQQL IT]

Have someone rock the wheel, while you're under it.
Look for something loose.
Box 1st

[3drburb]

What is the condition of the rag joint?

[3drburb]

Looking at your first post, we should says bad steering box or tires, then after another rotation it seemed to have gotten worse?

Tires unbalanced, a flat spot on a tire.

Do you have another set of wheels and tires to put on to test?

[chris989]

I found something,

installing new pads today and noticed the thin metal plate behind the brake pad has slid haveway out. It is not touching the rotor but maybe the pad being off plane the thickness of the plate is causing it to grab????

I will upload a picture when i get to the shop

[farmall]

Larger, crappy, unbalanced tires and wider wheels expose all the ailments of your 35 year old axle.
Find and buy a used axle. Put it on saw horses and replace everything from lock out to lock out. Bearings, ball joints, seals, rotors, calipers, hoses, tie rod ends, drag link and U-bolts.
Do it at your own leisure. It does not cost a fortune. Difficulty is low.
I took my knuckles to a friends shop to get the ball joints pressed out.
Clean and paint. Sell your old one and you have a rock solid investment in your rig.
How about a Detroit Trutrac?

[chris989]

Originally Posted by farmall

Larger, crappy, unbalanced tires and wider wheels expose all the ailments of your 35 year old axle.
Find and buy a used axle. Put it on saw horses and replace everything from lock out to lock out. Bearings, ball joints, seals, rotors, calipers, hoses, tie rod ends, drag link and U-bolts.
Do it at your own leisure. It does not cost a fortune. Difficulty is low.
I took my knuckles to a friends shop to get the ball joints pressed out.
Clean and paint. Sell your old one and you have a rock solid investment in your rig.
How about a Detroit Trutrac?

The axle is all new,, the truck has ~500k miles but the axle is new 456 gear, eaton posi, seals, bearing, all moog joints etc.

I have a truetrac in my 67 camaro and love it, It has never not works flawless on a launch and it is smooth as silk on the road. I am installing trutracs in my 78 ford.

[chris989]

this is the brake that lost it thin plate. somehow slipped downward?