wandering bronco

[jwhit]

i sure this has been gone over before but he is my issue
3 1/2 lift from bgy new 7degree bushings in the correct way
drop track bar and drop pitman arm new track bar bushings
3/16 toe in 33/12.5/15 tires new & disk brake kit

truck seems to wander lane to lane and when you go to brake
goes left and then right. steering box seems to have a little play
but not enough to cause this issue ? also i had king pins out and just added grease they seemed fine. but now i may consider changing them just to be sure this is not a issue. all tie rods seem to be tight with no play

 

[Justafordguy]

Sounds like you may need more caster. Have you checked it? Need at least 4 degree of positive caster to make it track straight.

 

[Bronco Junkie]

You probably need an adjustable track bar.

 

[Hozr]

Sounds like bump steer (track bar) issue to due to the lift. Are your track bar and tie rod parallel? The turn on braking is due to the front end diving and the difference in bar lengths.

 

[Justafordguy]

I would have though he would be OK with a drop trac-bar bracket and drop pitman arm right?

 

[carmi]

As others have stated, could be bump steer. I had similar problems that I was only able to cure by increasing my castor angle from 4 degrees positive to about 8 degrees positive. I used the All 4 Fun extended radius arms that already have about 6 degrees of castor built in and put in 2 degree bushings. Night and day difference in handling. Prior to that, I put in a front anti sway bar and stiffer 7100 bilstein shocks with little to no improvement. While my track bar and drag link appeared to be parallel, and measured out were less than 1/8" from being parallel, when I pushed up and down on the front bumper, I could see the steering wheel move back and forth quit a bit. I also have the F100 steering box which really places the drag link fairly level, in theory reducing the induced bump steer. Nothing worked like the increased castor from the extended arms. Went from scary to drive on windy mountain roads to a much more controllable and pleasurable experience. One thing to check, and something that did make a huge difference for me is your rear leaf spring u bolts. I had replaced mine and never went back and re-torqued them. When I finally check them, they were only at about 70 # ft. After re-torquing them, I noticed a lot less wandering.

 

[jwhit]

i think i will try changing steering box this week end since i have extra one that seems to be tight
i also considered adding spacer in front of trailing arms i think i get get 1/2 spacer and still have enough treads on nuts? if i am thinking correct this would help give more caster?
any body done this before?

 

[surfer-b]

i also considered adding spacer in front of trailing arms i think i get get 1/2 spacer and still have enough treads on nuts? if i am thinking correct this would help give more caster?

If I follow you correct on this you are gonna add a spacer on the radius arm between the arm and front of the 1st bushing where it attaches to the frame? If so this will do nothing but move the front axle forward the thickness of the spacer you add. You are not extending the length of the arm, its just moving the axle forward.
To get the caster where it should be, which will be ~8* +, you need to remove the 7* bushings, replace with 2*, this will get the front d-shaft angle closer to where it should be. Go get a caster/camber reading, I bet it will be close to -1.5* with the 2* bushings and 3.5" lift. Then you will need to rotate the yokes back enough to get the 8* +, so if the caster reading is -1.5* you will have to rotate the yoke back a total of 9.5*. This will make your Bronco drive the way it should as long as everything else is the way it suppose to be. Also with that much lift I would do a TRO and add a riser on the axle for the trac-bar.

 

[jwhit]

i am not sure what you are getting at about taking 7 degree bushings out and going with 2 degrees that seems like it would be worse? i can see your point about spacers just moving axle forward

 

[DuctTape]

Radius arm drop brackets are also a caster increase option, as is rotating the knuckles. Lots of threads on here on this topic, I learned by googling for them.

 

[Justafordguy]

I think Surfer-B was talking about having the knuckles rotated to get more positive caster. It's the best way but it is a major job so it's more costly.

 

[surfer-b]

i am not sure what you are getting at about taking 7 degree bushings out and going with 2 degrees that seems like it would be worse? i can see your point about spacers just moving axle forward

Yeah sorry I didn't make that clear, I was referring to rotating the yokes on the axle when you do this.

 

[jwhit]

i think i will swap out steering box this week end add a little more toe in
and if that doesnt help i think i will get drop radius arm brackets

thanks for the input

 

[Justafordguy]

Drop radius arm brackets helped more than anything else on mine. You can also try running around 28 - 30lbs of air pressure in the front tires. That seemed to help some too.

 

[jwhit]

swap steering box and added more toe in this helped some but i think i still need to add drop radius arm brkts

 

[DirtDonk]

Just out of curiosity, what year is your Bronco?
And what style of steering linkage are you running? New, old? Stock or aftermarket? In what condition?
I know you have new trackbar bushings and such, but are you sure that the lower stud and the upper bolt are not wobbling a little bit? A tiny bit of looseness in the trackbar will lead to noticeable wandering.
You can easily find exactly where any little bit of your looseness is coming from by performing "The Test" that every EB owner should perform any time their rig seems to be all loosey goosey or just exhibit some new strange behavior.
That's where you have a helper saw the steering wheel back and forth about a quarter to half turn in each direction. Do this with the tires fully on the ground and the helper working the wheel constantly while you watch for any monkey motion or loose components. Doing this you can see anything from a loose steering joint, to a cracked frame behind the box (more common than we'd like), all the way out to loose ball joints.

And always experiment with both tire pressure and toe-in adjustments. Your 3/16" is right where mine always was happiest, but it all depends on the overall setup of the vehicle as to what it likes best. Especially with different wheel offsets and tire sizes and ratings.
Air pressures for the street vary among us from about 25 to 35 psi front, with I think most coming in at 28 to 30 for their sweet spot. But I've varied mine by as much as 15 lbs to find that spot.

Good luck. If you have any pictures you can share of the front end, that'd be great too.

Paul

 

[jwhit]

1970 with stock linkage, all tie rods seem to have no play also track bar has no movment
top is on new drop down brkt that is welded every where i could get a weld with new bushings and bolt at top and new lower bushing on axle, the king pi9ns seem to have no play also but i am consdering changing bearings and seals to make sure these are not a problem. if i knew for sure that radius arm drop brackets would fix issue i think i would buy the adjustable ones from duff these seem to be a better option then the fixed drop that other venders are selling . but i am not sure that it is a caster problem
thanks for the input

 

[jwhit]

just went out for test ride and seems to pull to the right hard also notice around 35-40
i get a lot of shake in steering wheel i dont fell like it is death wobble but you can feel the wheel fighting in hand and it smoths out as i go faster at 60mph all i feel is pull to right
any input ?

 

[surfer-b]

Did it pull and shake before you did the toe adjustment? If so then try rotating the tires and see if the pulling goes away, if not then I would say its an alignment prob. Most of the time when one pulls its the tires, not all the time but most.
Did you add the lift or was it a PO? If you added it how did it drive before the lift was added, did the steering return to center, did it wander?

 

[bronconut73]

Get an alignment and ask for the alignment machine data sheet.
That way it will be as aligned as they can get it and you will have alignment specs like caster, to work off of.