One more steering thread

[Flintdog2011]

Hi All,
I am in the process of completing a frame off resto and have some handling issues. I installed a 2.5" susp. lift with a 1" body lift. My steering is very vague on center and is twitchy and darty with very small steering inputs. The lift seems to be more than 2.5", but I do have a much lighter engine, nv3550 trans. and atlas 2. I installed 7 degree bushings and radius arm drop brackets and the caster is now around 6 degrees. All bushings are new and everything is torqued to specs. I have some mild bump steer, but not to the point of worry. I also installed an anti sway bar in the front. I am thinking that I might need a track bar drop and/ or drop Pittman arm. What do ya'll think?

 

[Cvcoda]

I am by no means an expert (not even close), but I've been working on my steering for the last few months and I've learned a lot from everyone on here.

Maybe someone else can verify, but to me your track bar and drag link angle looks a little steep. So like you said, a track bar drop bracket and a drop pitman arm might be the answer. DirtDonk (Paul) always has good detailed steering advice, so hopefully he'll chime in.


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[Toddpole]

If you plan to wheel it much you should consider TRO and a Track bar riser at the axle. The riser is much stronger than a drop bracket. If it's going to be a street rig the drop bracket should be fine.

 

[Skiddy]

one other thing to check is the toe in, it will help with center a lot

 

[Flintdog2011]

Thanks guys. Mostly (90 percent street). My toe in is at around 1/8 inch, so I may take it to 1/4 inch. I thought the angles looked a little steep too.

 

[Joe473]

Check air pressure in those tires. Reducing a little below 30 psi helped me.

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[SavageBurro]

Also... triple check there is zero slop in either end of the track bar. Bolt holes tend to wallow out.

 

[thorgan]

Taking a close look at your photo, I might be able to provide some input on the dartyness of your steering.

The ball joint at the pitman arm end of your drag link appears to be an inch or so lower than the frame end of your track bar. When you're cornering, the chassis tends to roll around the axis of the frame end of the track bar. Now, any mismatch in the location of the pitman arm end of the drag link vs the frame end of the track bar results in an additional lever arm that ends up either amplifying (drag link end below the roll axis) or dulling (drag link end above the roll axis) the steering feel.

Now, imagine you're going into a left turn. The pitman arm pulls the drag link to the left and the body starts to roll to the right. Because of this body roll, the pitman pulls the drag link even more to the left and amplifies the turn input. The same thing happens when turning to the right because now the body is rolling to the left and pushing the drag link to the right.

Here's a little test - disconnect your sway bar. Does it get worse (the dartyness)?

Now, I'll give the vagueness a shot: When your drag link is at a steep angle compared to the tie rod, the initial steering inputs you give end up simply rotating the tie rod. It will rotate forward when you're turning right and backward when you're turning left. This effect will be diminished to the point of going away completely as the angle between your drag link and your pitman arm approaches zero. So, this is why your steering became more vague than what you're used to when you installed the 2.5" lift. This effect is called "dead center".

So, how does one fix all this? I would suggest a tie rod over kit to decrease the angle between the drag link and the tie rod. But, you need to make sure that your track bar receives a similar change in angle so that it ends up parallel to the drag link. To further complicate things, you need to make sure that the frame end of the track bar ends up approximately level with the ball joint of the pitman arm end of the drag link. Slightly below is ok but slightly above is still no good and prone to dart with steering input.

I know this indicates a drop bracket for the frame end of the track bar and, like was mentioned earlier, this is not as strong. I will definitely vouch for this as I had a drop bracket once and it broke on me at 65 mph on the freeway! But, this is necessary to get the proper steering geometry.

One final item of note - simply glancing at the relative angles of the track bar and the drag link can be misleading. You need to imagine a line drawn between the centers of the ball joints of the drag link and compare this line to the angle of the track bar. Usually this reveals a difference in angle between the two links that would explain any bump steer.

Sorry about the long post...but steering is definitely not simple and the relationship between the drag link and the roll axis is rarely explained.

 

[Flintdog2011]

I was just about to pull the trigger on a track bar riser and a drop pitman, but it looks like that would make the difference between the pitman arm and the frame end of the track bar even higher. The angle of the track bar is 17 degrees and the drag link is 16 degrees.

 

[DirtDonk]

As has been said, the angles do look pretty steep for a 2.5" lift. If you measure between the top of the axle tube and the bottom of the frame rail, you should be seeing approximately 9.5 inches, give or take.
If you have more than that, let us know.

But yes, you can easily benefit from the drop pitman arm and trackbar bracket. Unless you have much off-roading planned, I would not opt for the admittedly stronger trackbar riser and associated tie-rod over swap.
A drop bracket would be just fine for you. And simplify things by not going TRO for limited benefit at this point.

thorgan laid it out pretty completely there. But your pivot points at this point are where Ford put them (other than the steeper angle) and your angles are pretty much parallel at that 1 degree discrepancy. Not enough to worry about.
Right now most of your vagueness is two things the way I look at it.

The fact that your steering box is likely off-center, and the angles themselves.
So for now, first find out what height you're sitting at and why.
Did you get the wrong springs?
Is your anti-swaybar holding you up somehow (not likely, but not impossible)?
Even if you get it back down to 2.5 inches, using the drop arm and bracket are not out of the question. But add to them an adjustable draglink to fine-tune your box's on-center position and you should be 99% better in the vagueness department.

Is your steering wheel off center? Or did you move it to get it back to straight? If so that's not the right way to do it. Your wheel might be straight now, but your box is off of it's center position. Which is pretty important for steering feel.

Good luck.

Paul

 

[Flintdog2011]

I am measuring approx. 10 1/2 inches from the frame to the top of the tube. I disconnected the sway bar and it made no difference in the height. I was pretty careful when I installed the steering box to center it, but I will check it again. The steering wheel was off when I did all that, so I don't think that is affecting it. The front end is quite a bit lighter with the engine/drivetrain changes, so I think that's where the extra height is from.
I won't be doing a ton of wheeling, just dirt road cruising and pasture driving with some fire road stuff in the mountains.
How much does the drop pitman arm and drop bracket lower the angles?

 

[B RON CO]

Hi, yes, as mentioned, your steering box has a center point and if you are off to the right or left the Bronco will not track or steer as it should. I would not add toe out, maybe a little toe in, but if you did major front end changes you should get it aligned and get the numbers written down. Toe is the only easy adjustment, but knowing caster and camber will help you. I'm not against sway bars but they sure complicate figuring out handling issues. X2 on the drop pitman arm and track bar bracket. Do that before your alignment. Good luck

 

[DirtDonk]

...How much does the drop pitman arm and drop bracket lower the angles?

I would say about 2.5 to 3 inches drop. At least for ours.
But at 3.5" of effective lift, that indicates you use the dropped parts.
Even if they don't get rid of the funny business 100%, they'll make a big improvement.

Paul