Help, steering fab is driving me nuts

[Willowbilly3]

OK, now I know that a bunch of hotrods have ill sorted steering. I spent all day yesterday working on my pitman/drag link/steering arm. Just to have my tierod anywhere near level, this is how the steering arm came out. I really don't need advice on how strong it isn't, this is just a mockup. Basically the way the math works out to have the steering box and the axle both on the stops at the same time, the pitman arm is about 2 inches shorter than the steering arm (measured from the back of the spindle where it bolts on) Sooo, in order to not have like a 5 inch long pitman arm and a steep angle on the drag link, this is the best compromise I came up with, a steering arm 13 inches long with a 4 inch rise.
I see a lot of long pitman arms and now I know those steering boxes have to be hitting the stops before the axle, or else they must be like 40:1

I could move my box down a couple inches which would require redoing several days of work. I'm about ready to push it out in the weeds.

Any suggestions?

 

[bob w]

Willowbilly3,
I Just measured the set up on 4 of my cars and in each case the pitman arm, center to center is close to the same length as the steering arm, from the kingpin centerline to the centerline of the draglink attachment hole. There is a variation of a half inch one way or the other on them. The only one I've changed uses an Econoline box which had a very short pitman arm. The steering was too slow so I lengthened the pitman arm an inch and a half. Now it falls in the range mentioned above. It is not desireable to have the draglink parallel, except for appearance. There is a set of diagrams in the suspension section of RRR called Avoiding Bump Steer, that shows why. However, most cowl steering draglinks are parallel and those folks drive their cars. I think if front suspension travel is small, and most early Ford style setups have little travel, then bump steer must not be a big consideration. By the way, the pitman arms and steering arms in my set ups are in the 5" to 6" range because each of them has either an original pitman arm or an original steering arm. None have cowl steering, but they are all 'drag link down the side'. I don't worry about going lock to lock in the steering box as long as I get the front wheels to turn as much as needed. Unless you have a quick ratio box, I suspect you'll find a pitman arm and steeriing arm of the same length is about what you need. The biggest problem I see for you is finding a shock location because of the big sweep of the steering arm. If it was my car, I'd build it the way you have laid it out. I'd recommend, since you will be making both arms, that you have a couple holes in one, or both so you can fine tune the steering ratio. If the steering is too slow, minor adjustments while driving take a lot of steering wheel movement. If it is too quick, it darts around like a go kart.
I really like your project and especially the way you are using ingenuity and used car parts. That's my style too. Don't get frustrated with this, you're too good a builder to let this get to you.
Bob

 

[Unkl Ian]

What box have you got ?
I suspect some have more turns Lock to Lock than others.


I would start with a more conventional length steering arm
on the spindle,and see what happens.

If the steering effort is a little high,you can hook up your power steering.

 

[Willowbilly3]

The box is from a Chevy astro van. 3 1/2 turns lock to lock and you can see the sweep it covers on the cowl. I marked several arcs with the distance covered to have reference points for the amount of travel the steering arm would make.
My shocks would have to be in front of the axle and I'm not real crazey about that, plus I haven't even got into headlight placement.
I guess then maybe forget about the steering box using it's full range of motion and stop worrying about that. I really can't stand to look at a drag link that runs on a big angle.
Thanks for the ideas. I need to re-read the avoiding bumpsteer thread. I think for now I will shorten up the steering arm so I can get some steering on this car and move on, dial it in later when I get it on the road.

 

[Unkl Ian]

If the Drag Link runs at an angle, SIDE TO SIDE,it is NOT a problem.

The idea is the axle, and the Drag Link, want to travel through
similar arcs as the suspension moves.This refers to the side view,
not the top view.

Measure how long the steering arms are on the spindles of an Astro Van.
Going to be a LOT less than your first pic.
Make yours similar to what GM used,and don't worry about it.
As long as the box turns the wheels in the right direction,go for it.

 

[Willowbilly3]

That would leave a 5 inch long pitman arm and a very severe angle on the drag link.

 

[Willowbilly3]

oops, double post.
Well, when and if I ever build another car from the ground up, I will certainly be a lot smarter, but only about half as smart as I thought I was when I started this one.

 

[Bonehead]

Here is one I like...

 

[dawg]

you should add that pic to the salt car photo thread,

niiice...

 

[Willowbilly3]

If the Drag Link runs at an angle, SIDE TO SIDE,it is NOT a problem.

The idea is the axle, and the Drag Link, want to travel through
similar arcs as the suspension moves.This refers to the side view,
not the top view.

Measure how long the steering arms are on the spindles of an Astro Van.
Going to be a LOT less than your first pic.
Make yours similar to what GM used,and don't worry about it.
As long as the box turns the wheels in the right direction,go for it.

Unc, it isn't side to side that I am trying to deal with here. I want the drag link fairly level when viewed from the side.
Since the centers of the radius arms and the pitman arm are pretty much perpendicular, yes I actually planned that (and one of the few things that came out right on the first attempt), then keeping the radius arm and the drag link parelell will keep them in the same arc of travel, If I ran the stock astro drag link and the stock econoline steering arm all the geometry would be acceptable except the front of the drag link would be 13 inches from the ground and the rear would be 27 inches from the ground. I may not be the sharpest knife in the drawer but that is totally not acceptable and is actually the whole issue I am trying to get worked out with out some super fast steering ratio due to the longer pitman arm needed to get things leveled out.

 

[bob w]

As you can see in the pic above, the rules of correct steering are broken even on beautiful, expensive rods. And, it probably steers just fine. If I were in your position I would make the pitman arm the full length you have shown, but I would put three mounting mounting holes for the drag link one inch apart. I would shorten the steering arm to have the drag link directly above the shackle mount on the axle. The rise you have in the steering arm should be ok in your light car. The steering might be pretty quick, but hopefully not twitchy. If you have to slow the steering it would cause a slight angle on the drag link, but not too bad. It would be better if your steering box had the same sweep with 4 1/2 or 5 turns. Then you could get by with a longer pitman more easily. By shortening the steering arm you might find room for mounting the shock. Also, if the steering is pretty quick, a fair amoung of caster, 7 degrees or even a little more will keep it straight on the road. A large steering wheel reduces the feeling too, because minor steering adjustments require the rim of the steering wheel to move farther than with a small diameter wheel. In my Tub I have a very large steering wheel and it is what made the steering feel too slow. I lengthened the pitman arm an inch and a half and the feel down the highway improved a lot. Again, keep moving forward. You'll get it all worked out just fine.
Bob

 

[bob w]

Here's the ideal alignment for the pitman arm, steering arm and radius rod. Obviously, no cowl steering set up can meet this criteria. Lots of rods have cowl steering and drive successfully, so cheating is ok.

 

[Willowbilly3]

Today I wanted to be able to turn the steering wheel and see the tires turn. I went with a 12 inch pitman arm and a 10 inch steering arm with a 4 inch rise, just a temp arm, way tweaky so I added a brace up from a bottom bolt in the spindle and it's still tweaky. 10 inches out and 4 iches up is just way past the limits. Plus what I thought was a really stout and well braced steering box really isn't. I can't really use a larger steering wheel because of the small doors and room to get in and out. I am at 2 turns lock to lock now and if I shorten the steering arm or lengthen the pitman arm any more it will be even less. It seems like every part of my whole system is some sort of compromise and it's compromised out. I really need to step away from it for a while, go check out an old econoline pickup for it's steering box tomorrow. If that is koposetic then I think I'll scrap this whole mish-mash of parts, abandon the cowl steering idea and use all parts that belong together.

 

[bob w]

I used a '67 Econoline box in my Tub. I don't know about the other years but the '67 is a little hard to use. There is a partial spline on the pitman arm and the sector shaft and a pinch bolt that fits in a cutout in the sector shaft. This makes it difficult to change the position of the pitman arm, getting it to point straight down when going straight. I have used 2 iron Corvair boxes that I reversed (easy) and it ismuch easier to clock the pitman arm. I know lots of people use F100 boxes but I have no experience with them. You might want to look at old Chevy van boxes too (up to '67). Sometimes you have to take a Sawzall and undo days of work in just a few minutes.
Bob

 

[Willowbilly3]

I hear the F100 box is easy to reverse and long enough to get out the side. I am going to look at a couple of those. I do know where a couple econolines are, no corvairs left around that I know of. Also a 48-49 F-1 I need to check on.
No stranger to cutting stuff apart but getting tired of it for sure. Almost every part of this car has been cut apart and rewelded at least a couple times. I spent 2 days once just reworking one door and the opening to get the gap and the body line right. No wonder I am only 1/4 done in 5 years.lol I'll probably be too old to drive before I get it running.

 

[Willowbilly3]

Yesterday I tore it all down and pulled the tub off, then mounted all the steering back up. I had shortened the steering arm back and dropped it too. Now with the drag link on more of an angle, probably 3 inch drop, one of the things I notice is that it actually pulls the whole chassis up and down when I steer it. I now have only 1 1/2 turn lock to lock and it puts a lot of stress on all the mounts, actually tweaking the box and the whole framework a little too.
I spent quite a while staring at the whole thing and measuring. Other than completely starting over I came up with another brain fart. Make a second pitman mounted lower and run a number 60 chain and sprockets from the other box down to it. I looked at my favorite farm store and the stuff to do it with wouldn't cost much. I tore apart a 37 Ford box I had and that pitman shaft would work fine. Whatcha think? I know it would require an idler to keep it real tight.
Also do any of you have any bend in your drag link? I always thought it was unacceptable but I have a drag link from an econoline and it has a bend in it to clear the tire.

 

[bob w]

There was an outfit making a chain drive steering relocator that was featured in a magazine 5-6 years ago. I saw ads up til maybe a year ago, so I don't know if they'r still around. Wouldn't suggest you buy one anyway. Just confirming that your idea has been done commercially. You can adjust your steering ratio with different size sprockets too. The commercial unit did not have an idler, just a way of cinching it up tight. At any rate, I think you are going to need to have more turns from full left to full right.

 

[Willowbilly3]

I remember that chain drop box. Thanks for the idea to tighten the chain, it would be easier to slide the slave than makeing an idler. I have done some measuring and I think a 5:8 ratio would get my 3 1/2 turns back and still have an 8 inch long pitman arm. A 5 inch pitman would make the ratio on the chain sprockets 1:1.

 

[dawg]

What I noticed looking at your car verses the salt car, is tha ton yours, you seem to be attemting to follow the angle of the frame rail, the steering shaft on the salt car parallels the wish bone?...

 

[Willowbilly3]

I actually would like it to parelell the ground. but now with the chain drop I will shoot for parelell to the wishbone