Major bump steer with leaf spring sas, help

[n_bannerman]

Not sure if this should be in here or steering but I am having major bump steer with a leaf spring sas. Running a rear shackle setup with rancho 44044 spring set up spring under for a few months and have been fighting to get rid of the bump steer. Also when I corner hard it feels as if the whole axle will shift side to side, but everything is solid and tight and when I turn the wheels with the truck stopped it will cause the front to flex. With all this side to side force it has caused my steering box bolts to back off. Is there anything I can do to fix the bump steer other then going to a 3 link?
Thanks in advance!


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[alwaysFlOoReD]

Pics please. I haven't played with a SAS and can't picture how you would get bump steer. From what I've read the track bar needs to be parallel and the same length as the pitman arm down to the knuckle. Then there is an drag link [?] to the other side. How do you get bump steer when both sides are tied together with a solid link?

Richard

 

[brinker88]

Some taller lifted leaf springs WILL require a track bar, as well as crossover steering to get the steering angles better.

 

[n_bannerman]

The crazy part is that I only have about 2" lift upfront from stock.
Here is a picture, it's hard to see but you can see the steering and it's almost flat.

I'll try to get a better picture tonight.


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[n_bannerman]

Found a side view on my phone.

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[brinker88]

I thought you had reverse shackles? I see a slider box up front

 

[koochman450r]

hmmm.. You said rear shackles. If you have rear shackles and front slider boxes that would cause all types of problems. I don't like slider boxes and think it is a poor thought out bad idea.

 

[Ford78]

A trac bar will help alot. I had has the shifting from side to side too.

 

[4.0B2]

Yeah I'd recommend a tracbar, not required on all leaf axles but....

 

[n_bannerman]

Did have sliders but have changed to rear shackle after those photos.


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[n_bannerman]

I do have 1 more leaf for the leaf packs, maybe I'll see if that will fix it, think being to soft could be causing it?


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[The Jester Race]

Not sure if this should be in here or steering but I am having major bump steer with a leaf spring sas. Running a rear shackle setup with rancho 44044 spring set up spring under for a few months and have been fighting to get rid of the bump steer. Also when I corner hard it feels as if the whole axle will shift side to side, but everything is solid and tight and when I turn the wheels with the truck stopped it will cause the front to flex. With all this side to side force it has caused my steering box bolts to back off. Is there anything I can do to fix the bump steer other then going to a 3 link?
Thanks in advance!


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Check your tie rod ends and jam nuts. Any slop in your steering linkage contributes to bump steer.
Check your shocks. Weak or worn out shocks can't stabilize the axle sufficiently and can contribute to bump steer.
Check your caster angle, too much or too little can contribute to bump steer.
If you're using rubber spring bushings, try polyurethane bushings. They're stiffer.
Try tightening your spring to hanger bolts, spring to shackle bolts, and shackle to hanger bolts a little more.

Basically try to find and eliminate any looseness or slop in you front suspension and steering.

You can throw a steering stabilizer on there, it won't fix the bump steer but it will mask it some.

Hydro assist or full hydro will eliminate bump steer.

 

[bobbywalter]

bump steer or death wobble?


there is a big difference between the two.


toe and caster can be very large factors. need to know what it is your battling though.

 

[n_bannerman]

Bump steer, every small bump in the road is causing my steering wheel to turn or the truck will dart. Had death wobble when it had the sliders on the front, changed to shackles and solved it but the bump steer won't go away. Also it is set low enough that I only have about 4" of up travel before contact with the frame so I don't think it would be the drag link and my castor and toe are both pretty close.
Thinking that as soon as I can find a d30 from a xj, I will just do a 3 link on the front and ditch the leafs.

 

[bobbywalter]

hmmmm........






what is the caster at? i am surprised of the issue with the gentle arch of the springs and it being spring under.


but the location of the drag link if the caster is 5-8 deg may be the issue. i suspect you need to move the tie in point to the frame rail or at least just inside the spring on the passenger side. you would be fine if you were over rail on the other side with the steering gear but i see that setup as out of balance.

its counter intuitive, but i have had it happen a few times and moving the tie in point helped....basically going to a t setup like a eb or some jeeps.