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High steer on a street driven Blazer?

camok5

camok5

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Started getting death wobble on my 1971 Blazer (Dana60, crossover and high steer, PSC hydro assist) so I replaced the tie rod ends, set the toe, rotated the tires etc. Finally pulled the king pin springs and bushings out and replaced them with new ones. Test drove it after each thing and only noticed a slight improvement after I did the springs. I decided to put in spring eliminators and it wasn’t till I added two washers on top of those did I get it to go away.

So my question is, is high steer putting an extra load on the upper king pin causing the death wobble and wearing out the springs faster? Should I move the tie rod to the stock location to relieve the extra stress seeing that the Blazer gets driven on the street more than off-road? I’m mostly surprised that it took two extra shims on top of the eliminators to solve the problem.
 
Have you had anyone help you diagnose the complete system?
I think many times there are underlying issues that don't get attention, and don't discount the tires themselves!
 
I’m sure high steer adds a lot of stress but it should be manageable with maintenance. If you’re getting DW with hydraulic assist I’d say some is still wrong. I have high steer, no assist or stabilizer and unbalanced 43’s with no DW. Mine doesn’t see regular street driving but it sits for long periods (kp spring fatigue) and I can still drive it some without issue.

Have you checked the caster?
 
The Death Wobble was definitely coming from the king pins. I’ve gone through everything on the front end more than once and this isn’t my first blazer that I’ve built with it before. The best explanation of death wobble I’ve heard before is that your front end is like a tuning fork and once you hit it on something it sets it off. Anything bad or even slightly out of adjustment can cause it.

I’m more try to figure out if high steer is putting extra stress on them causing premature wear and is it more suitable for an off-road only type rig? Oh and I think the caster was at about 5*
 
whan was the last time you checked the king pin bushings ? new springs ?

if not its time for new springs . they sag out and the more they sag the more death wobble will happen .

anymore for big tire trucks i recommend this kit . it works good i used it on a truck with 20" total of lift and 46" tires no wobble at all . https://craneaxle.com/default/dana-60-king-pin-spring-eliminator.html

and the 5* caster is a bit on the weak side . should be up mid 6* range from what i recall guys saying works good .
 
He eliminated the springs already.
Ive driven mine for several hundred miles on road, and the only time Ive had an issue was when the draglink was loose, so its definitely not a trail only mod, in fact that was why I put it on mine. I run 39.5/15’s without a problem, and use balancing beads in the aluminum rims.
 
camok5 said:
Started getting death wobble on my 1971 Blazer (Dana60, crossover and high steer, PSC hydro assist) so I replaced the tie rod ends, set the toe, rotated the tires etc. Finally pulled the king pin springs and bushings out and replaced them with new ones. Test drove it after each thing and only noticed a slight improvement after I did the springs. I decided to put in spring eliminators and it wasn’t till I added two washers on top of those did I get it to go away.

So my question is, is high steer putting an extra load on the upper king pin causing the death wobble and wearing out the springs faster? Should I move the tie rod to the stock location to relieve the extra stress seeing that the Blazer gets driven on the street more than off-road? I’m mostly surprised that it took two extra shims on top of the eliminators to solve the problem.
Click to expand...


I ran high-steer and crossover in my '72 with hydro-assist.... very similar setup from the sounds of it.

I had massive DW when the truck was on a set of small diameter "rollers" for a brief period of time. When I swapped to my 38s it never came back. Everything in my steering and suspension was brand new and freshly installed.

The issue definitely seems like a "harmonic" issue. A bump in the road starts an oscillation in the front suspension which then couples with the natural resonant frequencies of the various suspension components....it IS like a tuning fork, but is almost worse because the energy builds on itself and the intensity increases over the next few seconds until you have no choice but to slam on the brakes to dampen the energy.

It seems like an odd suggestion, but I'd always wondered if adding a front panhard bar (yes, even on a leafsprung truck) could be a magic bullet for DW? :thinking: The slow-motion videos I've seen of DW show that the front leafsprings seems to shift pretty wildly back-and-forth which jerks the wheel and seems to aggravate the entire event. Locking down that lateral movement of the axle always seemed like sensible experiment and possible cure, but I never bothered to mess with it once the big tires went on and the DW disappeared.


-G
 
My dodges had pan hard bars and had death wobble. I've seen loose components, alignment, tire type, tire balance, shocks, all sorts of things be a factor to death wobble.
 
I had some nasty death wobble last year on the K5 with new everything on the axle. Got rid of my worn TSL and got new Toyos. Its perfect again.
 
Death wobble is a steering problem, not a suspension problem. Adding a panhard bar won't fix it, on the vehicles that get this the worst (Dodge/Rams and Jeeps) it's usually the panhard bar that causes it.
 
I guess it still could be the tires even though they’ve been balanced and I rotated them front to back and inflated to max pressure all of which didn’t have even a slight effect on the steering feel.
 
max psi has to do with weight .

i found years ago that max psi to what the tire needs is 2 different things . my k10 on 1tons and 38x12.50x16.5 tsl bias ply was 25 psi max and i got the best ride / and feel and wear from the tires this way .
 
sweetk30 said:
max psi has to do with weight .

i found years ago that max psi to what the tire needs is 2 different things . my k10 on 1tons and 38x12.50x16.5 tsl bias ply was 25 psi max and i got the best ride / and feel and wear from the tires this way .
Click to expand...
First thing I do when I get one of my pickups back from the tire shop is let air out of the tires.
 
mrk5 said:
First thing I do when I get one of my pickups back from the tire shop is let air out of the tires.
Click to expand...

And the second thing I do is loosen all the lug nuts and torque them correctly (OCD :doah:). That way, if I get a flat I’ll be able to get the lug nuts off without killing myself.
 
camok5 said:
I guess it still could be the tires even though they’ve been balanced and I rotated them front to back and inflated to max pressure all of which didn’t have even a slight effect on the steering feel.
Click to expand...
Max rated tire pressure is for when the tire has its max rated load on it. At all other loads, the correct pressure is lower - proportionately.
 
rampage said:
And the second thing I do is loosen all the lug nuts and torque them correctly (OCD :doah:). That way, if I get a flat I’ll be able to get the lug nuts off without killing myself.
Click to expand...
That is true, I do that as well.
 
Assuming you have checked spring bushings too? I had nasty death wobble on an old 4Runner that had a 60 under the front with reverse high steer, spring eliminators, and hydro assist. The rear upper shackle bushings were toast. Once they were fixed, I had no problems driving on the street
 
1977k5 said:
Death wobble is a steering problem, not a suspension problem. Adding a panhard bar won't fix it, on the vehicles that get this the worst (Dodge/Rams and Jeeps) it's usually the panhard bar that causes it.
Click to expand...

You are not much of a salesman. LINKS AND COIL OVERS. I have not had death wobble for 14 years.
 
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