1972 conversion 4x4 has a wierd steering problem

[spencer2986]

While sitting still, I turn the steering wheel left and the whole truck pretty much lifts up and it feels as if the steering wheel wants to pull back. The same goes for turning left but it dips down and wants to pull the steering wheel back. Any idea as to why this may happen. It has a 6 inch lift and the dropped pitman arm that I thought would solve this problem.

[Bhelton]

Sounds like a track bar issue
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[spencer2986]

I'm sorry I meant to say when I turn RIGHT, it goes down.

What would I have to do to fix this track bar if that was the problem. Do they sell aftermarket ones or is it more of an adjustment?

[Ol Blue K20]

After work I'm going to try this in my K20. Is your truck stock height or lifted? Seems to me all of the ones I have had did this.

[spencer2986]

Originally Posted by Ol Blue K20

After work I'm going to try this in my K20. Is your truck stock height or lifted? Seems to me all of the ones I have had did this.

It's got a 6 inch lift with 315/75/16 tires. Funny cause its the same truck in your avatar picture, blue and white cheyenne.

What are you goin to try? moving the steering wheel back and forth...?

I cant seem to find any aftermarket track bars that would fit my truck

[Ol Blue K20]

yeah, I''ll try it before I shut down my computor, Yeah I like the blue & white combo someday I'll quit driving it for a while and paint it ( the patina is a little overwhelming)

[Bhelton]

I've built a couple track bars for custom applications, you may be able to find one to modify to either shorten or lengthen
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[spencer2986]

I'm just surprised that they don't sell one being such a "common" lift and all.

Can you please somewhat explain to me why I would need one either shorter or longer? I never even thought about the Track Bar until you mentioned it.

[Ol Blue K20]

I just went out and tried it and on left it lifts on right it dips. It's not alot an inch or so, but it seems to me it was more noticable on my others that were lifted. This one is still stock ( I haven't attacked it yet)

[ryanroo]

What wheels and tires? it sounds like a combination of scrub radius and camber changing during a turn. you'll feel it more with wider tires and less backspace.

Ryan

[spencer2986]

Hmmm alright well I guess its a relief to know this is "normal" for there to be some movement but mine is prob a tad more than an inch in each direction.

I have brand new BF Goodrich A/T 315/75/16 tires and I'm not sure what kind of aluminum rims are on it but they are the common ones you see a lot on these trucks with the circle wholes spaced out relative to the 8 lugnuts.

Whats the best way to eliminate most of this or is it pretty much just the way its going to be?

[ryanroo]

Originally Posted by spencer2986

Hmmm alright well I guess its a relief to know this is "normal" for there to be some movement but mine is prob a tad more than an inch in each direction.

I have brand new BF Goodrich A/T 315/75/16 tires and I'm not sure what kind of aluminum rims are on it but they are the common ones you see a lot on these trucks with the circle wholes spaced out relative to the 8 lugnuts.

Whats the best way to eliminate most of this or is it pretty much just the way its going to be?

you can run a rim with less backspace, or what may be more of an issue, depending on the way it was converted, is the caster angle. if there is a lot of positive caster it will swing the left wheel/tire down and backwards as you turn left(raising the drivers side of the truck) and the opposite on a right turn. you dont need more than 3-8 degrees of caster depending on the axle.

Ryan

[spencer2986]

From what you mentioned, I have a lot of positive caster then. I hope it isn't a big issue so I guess I'll do my homework on how to fix it on a solid axle vehicle.

[Vintage Windmills]

Originally Posted by ryanroo

What wheels and tires? it sounds like a combination of scrub radius and camber changing during a turn. you'll feel it more with wider tires and less backspace.

Ryan

Even if he is noticing it sitting still? That would produce more of a rocking or tilting action. I'd guess more of an issue with the steering linkage running at an angle due to the lift. If thats the case, there'd be an up/down component to the force coming off the pitman arm if it doesn't drop enough to restore the steering bar to horizontal.

[GASoline71]

Sounds like a normal lifted rig to me.

The reason companies don't sell track bars and pitman arms, and other accessories as a part of the "common" kit... is so they can gouge your for a crapload of money for them.

Gary

[TBONE1964]

I don't own it anymore but I have had a 69 3/4 ton with a 4 inch lift and 33 BFG's that did the same thing. A friend of mine had a 71 that was bone stock that did this also. It has to do with the articulation of the steering and you will notice it on anything that has a leaf spring front suspension with a solid axle.

Yes this is "normal"

[spencer2986]

Originally Posted by Vintage Windmills

Even if he is noticing it sitting still? That would produce more of a rocking or tilting action. I'd guess more of an issue with the steering linkage running at an angle due to the lift. If thats the case, there'd be an up/down component to the force coming off the steering box since the bars are no longer horizontal.

And that's what threw me off. I have a dropped pitman arm and a block under the steering arm just so the linkage would be level.

I wasn't sure if this was "normal" or not b/c it just seemed a little excessive. I understand this isn't modern technology but had to ask anyways.

[ryanroo]

Originally Posted by Vintage Windmills

Even if he is noticing it sitting still? That would produce more of a rocking or tilting action. I'd guess more of an issue with the steering linkage running at an angle due to the lift. If thats the case, there'd be an up/down component to the force coming off the pitman arm if it doesn't drop enough to restore the steering bar to horizontal.

Yes.

even if the drag link is at an angle there wont be much of a vertical force vector. it will be there for sure but not enough to physically move the truck that much. sitting still is the same as moving as far as scrub radius is concerned. scrub radius is the arc the center of the contact patch of the tire swings as the knuckle turns. the less backspace the more the scrub radius. that will magnify the movement of the wheel and tire vertically as the knuckle cycles from left to right. if there is to much positive caster(or negative, but there would be a lot worse symptoms if it was negative) the invisible point that represents the center of the contact patch at the axial center point of the wheel will move even more in the vertical plane. this is further amplified if you have a wider tire. my guess is the wheels are 10 inches wide and have a 4 or 4.5 backspace. that leaves the center point of the contact patch .5 or 1" further out from the face of the mounting flange. that is already a couple inches out from the pivot point of the knuckle. that would make the scrub radius probably 4-5" then with a 35 12.50 the outside of the tire is another 5 or so inches from the scrub radius. that just makes it more noticeable. in fact you probably barely notice it in motion because of all the body roll and weight shifting. sitting still is when it is the most noticeable.

if you have a chance bolt a set of tires and wheels from a '01-up chevy on it. i would be the noticeable height change is greatly reduced.

Ryan

[Vintage Windmills]

Interesting Ryan. I get what you're saying now since its not zero camber or zero caster. With some caster or camber it seems like that would create a rocking motion (left side rising as right side is falling), right? I realize that zero caster and zero camber wouldn't be good for handling or tire wear though.

[ryanroo]

Yep. with zero caster there would be no vertical change. or zero change if the axis of the knuckle had no angle.

Ryan

[mcmlxix]

with 6" of lift I would concider cross over steering.....

here are TWO example of a kit... it depends on what axle you have....

http://www.northwestfab.com/Dana-44-...Arm-_p_90.html

http://offroaddesign.com/catalog/Dana44crossover.htm


Description
One of the best upgrades for your OHV is to upgrade your steering to a quality NorthWestFab Crossover/Hi-Steer system. Stock steering designs in vehicles do not adjust well to geometry changes due to lifs and the stresses of larger tires. This results in your vehicle suffering from bump-steer, roll-steer and loss of steering movement when the suspension is articulating. Our Crossover Steering Kit eliminates all of these ill effects by changing your steering geometry from "push/pull" to a longer laterally moving draglink that connects from your new pitman arm, to passenger side steering arm mounted to the knuckle. This Kit is designed for vehicles running Link Type Suspension or Spring Under Axle.

[spencer2986]

I would prefer not to buy a whole kit if possible b/c I already have most of the parts shown.

As mentioned earlier, would a modified track bar help my situation?

[ryanroo]

a track bar wont help.

if you get crossover, then think about a track bar. but either way it wont change the movement we are discussing.

[spencer2986]

Gotcha. Well once this snow clears up a little I will take the truck for a ride and see how she drives and steers. I havent had it on the road since the new tires so it may need aligned. Is it pretty important to have these solid axles vehicles aligned after new tires are put on?

I'm not familiar with the older set-ups so some pointers are welcomed.

[ryanroo]

with a solid axle your camber and toe settings shouldn't change (unless you adjusted the toe). the camber is set by the manufacturer of the axle. it should be the same unless the ball joints are worn or the housing is bent. the caster very likely changed with the lift, depending on how the lift changed the relationship of the frame to true level, the angle of the shackle, and depending on if the springs/kit had a caster shim included. that number is best around 6-8 degrees positive if you have a dana 44 or 10 bolt. if you are running a D60 they work best around 3-4 degrees.

in case you are not familiar with the terms,

Toe: toe is the relationship of the front tires to each other. toe in is both tires steering towards each other. toe out is opposite. toe out is only used with fwd cars usually. your truck would need a slight toe in. adjustment is made by lengthening or shortening the tie rod

Camber: camber is the relationship of the tire/wheel and the ground at a true level from the side. if you put a framing square against the side of the front tire with it pointed strait, 0 camber is perfectly square. negative camber is tipped in at the top and positive camber is tipped out at the top. for all the likely axles you have, this is factory set and non adjustable.

Caster: caster is the relationship of the line drawn through the axial center of the steering pivot and the ground at a true level. if the line tips toward the back of the vehicle at the top this is positive caster. towards the front and you have negative. this can be affected in several ways. the most normal way is lengthen or shorten the shackles. lengthen and the caster goes positive. shorten and it gets less positive. you should always have some positive caster or you will have the scariest truck in the world to drive. another way to change it is with a wedge shaped shim between the spring perch and the spring pack. another way that is often overlooked is to alter the relationship of the frame and the ground at true level. if you raise the rear more than the front you have effectively reduced your positive caster.

toe and camber are settings that contribute heavily to tire wear. caster is generally considered to have no affect on tire wear.