Death wobble

[JT88K5]

I am running a d60 up front, rebuilt except for kingpins. It was a takeout from a Cucv. I had a guy do the axle rebuild, new seals bearings u-joints and installed an elocker. I asked him to check out and replace the kp bushings, but I don't think he did. He said they looked OK and no way to really verify until you had it mounted and with wheels an tires on. Running 3" ez rides with 1" zero rate and crossover steering, new tie rod and drag and steering box from ORD.

Last night I was on a shitty semi paved road with lots of pot holes. Even as low as 5-10 mph I had terrible death wobble. I had to come to a complete stop several times. A single pot hole on one side or the other doesn't seem to upset it too much. Lots of potholes throws it into bad wobble immediately. I have hit some bumps on paved roads where I have felt a bit of wobble but nothing like I had last night.

My suspicion is the kingpins/bushings, since that is the only thing in the suspension and steering that is not new. How do I verify the kingpins are bad?

 

[skunked]

Replace the upper bushings and springs. Visually it's tough to spot a weak spring unless you can compare it to a new one.

 

[JT88K5]

Seems hard to believe that just a little bit of movement can cause such a violent reaction. I'm not arguing, it just hard for me to visualize/understand the dynamics between the cause and symptoms on this particular issue.

Can one replace the springs and bushing with the vehicle on the ground?

 

[nvrenuf]

No, you'll need to jack the tire up so it's off the ground. You don't need to remove the tire or anything else, just get the tension off and remove the caps. You'll need to grease the new parts after installation.

 

[rampage]

Score you replace the springs you can add a couple washers on top of them to give them a 'preload'.

 

[skunked]

Once you see kingpin design and how's it preloaded it will make sense

 

[sweetk30]

adding shims you need to watch what you do or it will be to tight and have memory steer.

the sping if it sags more than 1/8" then time for new .

I have put in a few crane offroad urethane spring eliminator kits and bronze bushing kits for people . the bronze bushing alone firms them up over the nylon that fits sloppy in the knuckle . 1 I did was on a guys truck with 15year old swampers that wabbled all over . when I was done rebuilding the front and using the crane kit and bronze bushings you could do 65mph up the highway 1 hand on the wheel .

also if there is any scorring or pitting on the king pin = time for new .
and if play in the bottom there a tapered bearing/race = time for new .

any help needed just ask I have done over a dozen king pin jobs on dana 60's . heck I got parts in stock for most of the common stuff.

 

[ChrisPerry]

How much caster does the front have? Too little caster can lead to death wobble also. (Like the wheels on a shopping cart if you get going fast)

 

[JT88K5]

ChrisPerry, Here's the alignment sheet. Do you think those are decent numbers all around?
SweetK30, I may be in touch. I'm going in for a lower back tuneup Tuesday, probably won't be able to really do any wrenching for a month or so.

 

[ChrisPerry]

7° ~ is awsome. It would have to be down around 2° or less to cause death wobble.

 

[sweetk30]

x2 on alignment specs for a lifted solid axle of our vintage .

hit me up If I can help . I don't work during the day just night so most any day I am in my home shop .. .. the man cavern link below.

 

[JT88K5]

Thanks to both of you for the assist.

 

[sweetk30]

woo wooo wooo wait a min . . . that person set you up with a ifs 4wd s-10 alignment .

but that dont matter much for us . the no.s are what we need .

i just re read that now i am home . . . how did the caster & camber change after ? dana 60 has no adjustment unless $$$ parts are used .

 

[ChrisPerry]

Lol, I saw that too. I figured leaning the truck while climbing in and out could change the readings a little.

 

[sweetk30]

no not that way . the truck would have to stay like the way it was pulled.

i did alignments for years .

a head/target moved / brake bar wasnt holding brakes tight wheel rolled / turn plates full of rust and junk making them skip when doing a caster sweep .

 

[ChrisPerry]

a head/target moved / brake bar wasnt holding brakes tight wheel rolled / turn plates full of rust and junk making them skip when doing a caster sweep .

Are you speaking engish still? J/k

 

[sweetk30]

speeking alignment specifics .

head/target = thing clamped on each wheel the machine reads for info to calculate .

brake bar = put on to hold tires were the 1st reading was taken to the tires dont roll on turn table/plates and mess up head readings .

turn table / plates used to let the wheels turn and roll during a caster/camber sweep and setting toe . up here in the rust belt these get full of crap / rust / junk bad from all the winter crap we deal with .

is this info better for you @ChrisPerry j/k back