Bad wobble at 25

[91sasexplorer]

Hey everyone I need your help very bad wobble at 25MPH like the front end is going to shake out ! I just did an sas with a leaf spring front end dana 30 on 38.5 I don't have shocks yet but.. I have a trac bar ! I set the castor 3 time frist is was 10* then I went to 0* now it is on 6* I dont know what to do now...So maybe you can help me out !!!

 

[sparky2263]

Sounds like a bent wheel or bad tire. Jack it up, spin the tire and take a peek.

 

[91sasexplorer]

Oh sorry It has new wheels and tirea

 

[91sasexplorer]

This I a death wobble

 

[Blee1099]

Check the trac bar. Also if you have a body lift, that can easily cause the wobble. Every SAS truck I've been in has some sort of wobble. Usually its the trac bar not being designed properly or being loose.

 

[Rick]

Make sure your toe is set correctly. You should have 1/8" toe in. I swapped out one busted tie rod end and got the "death wobble" before I was able to set the toe correctly.

 

[JDraper]

Do you have a front stabilizer installed? When I did the SOA on my Sammy, I had a nasty death wobble at certain speeds. I added a good stabilizer, and it killed the wobble. I'd also install the shocks and check it then. They will help dampen out some oscillation..

 

[Rick]

There shouldn't be any wobble without a stabilizer on the Explorers. I don't have one and most of the Ex's I've seen with SASs don't have them either. Find the problem before you add a band aid...

 

[JDraper]

Did you have everything balanced when the tires were mounted on the rims? If you have a wheel out of balance, that can also lead to some wobble.

 

[SVO]

Ok let's revise this a little more:

Is the body swaying back and forth: (IE: death wobble)

Or is it the front end schimming? (shaking wheel and/or frontend)

Does it do it while accellorating?

Does it do it while braking?

Dose it do while steady cruising speeds?

Are you sure the wheel base is square?

do you have a drop pitman arm?

Is the alinement correct? (IE: toe, caster, camber)

Are all the steering components new?

Is there a body lift on this truck?

 

[91sasexplorer]

Ok I work at a 4X4 shop I have dont about 100 lift kit in the past year !
But I HAVE NEVER DID A sas from scratch! I did an alinement it is about 15* on steer ahead,, castor off of the wheel I 0.50*,, castor off of the axle is 6* the leaf spring mount on the front, right side from left is off about 1/16 . it happens about the same speed 25 on the dot.... the axle is still and the tire are whipping side to side if you hit the brakes to stop and slow down to 5mph it will stop!

 

[91sasexplorer]

I thought it was a trac bar so I mount one on there from a f 250, there is no body lift on the truck and no drop pitman arm the SAI is dead on

 

[TheRookie]

First off did you align the truck properly or use a hunter machine? THe hunter machine is pretty much worthless with an SAS, that may be part of the problem. THey go bonkers when you change things that much.

Next, it really REALLY sounds like Toe thats why I asked about alignment. Assuming you did it the oldfashioned way there are only a couple possibilities.
Wheelbearing
Rod end
ball joint.

Check all of the above. a wheelbearing is verry possible depending on what you set up.

 

[91sasexplorer]

Hey everyone I just want to say thank you very much for all your help!
I did like RIck said and it worked some what......it wants to start at 25 but , I got it to 55mph now!
I am going to do dual stabs and 4 shocks on the front.
Hey Rookie its a John beam 3d Its ok !! And eveything is new inside and out !

 

[Josh]

FYI,
Just because your tires and wheels are new doesn't mean they arent defective. I had 1 or 2 tires that could not be balanced. Also the new rims they were mounted on were also a little off. One of my wheels took 10 ounces to balance.

 

[91sasexplorer]

LoL 10 Ounces thats baby sh%T I do about 10 lift kits a week I just did a H2 with 44s on welds it took about a half of a bax of stick on weights I dont care if it shakes
but a death wobble ! I tried like rick said and turned it out about and 1/8 it work a little..... I did 6 shocks on the front and 6 on the rear today it rides ok! Its just a mud truck ! I still think Its a castor deal I am going to try 8*p thats what jeep calls for, plus the tires are Ground Hawgs! But I really do thank you for all your help!
I have done sas's on chevys but every think was in a kit...

 

[osker75]

on my jeep i had the same thing and it had to do with my sway bar

 

[TheRookie]

You shouldnt be using stick on weights on a tire that size. Its a total waste and even if it seems balanced it wont actualy be perfect. Even 35's should be internaly balanced.

 

[Josh]

Just curious what you mean by internal balance?

 

[sparky2263]

I think he means static balance. Sticking the weights on the centerline, to the inside of the wheel.