Turning radius differences

[Buffman]

Background: 1937 Dodge pickup axle, w/ECI Camaro disc brake conversion on stock spindles. Corvair reversed steering box mounted on the top of the frame, custom made steering arms.
Problem: the throw from the pitman arm on the box is 21"centered, 24"left and18.5" right. So what gives?
Yes, this is my 1st T build but not my 1st rodeo, used to build dune buggies and race cars in the early 80s.

 

[Buffman]

Here are the pics of what I'm talking about

 

[Neshkoro]

Something is preventing the wheels from turning more. A turning stop??

 

[Buffman]

I pulled both of the stop bolts, cleaned them and ran them all the way in seated.
Nothing is hooked up to stop their movement.

 

[AusBucket]

Turn the steering full one way, then count the turns to full lock the other way. Come back halfway and see if the pitman arm and steering wheel are on centre. The pitman arm may well need to go round a couple of splines to be on centre. Hope this is helpful.

 

[HenrysT]

How is your wheel alignment? When the wheels are straight, is the steering arm centered over the axle? Are the wheels at the same angle when at full lock?

 

[AusBucket]

I will add to my above post and say that it's more likely the steering wheel is out, as most pitman arms I've seen are keyed to the steering shaft. Another way to check is to measure from the end of the steering arm across to a fixed point (opposite chassis rail)at full lock in both directions. Centre for the pitman arm will be halfway between these measurements, and hopefully it will be pointed straight ahead.
Two things to check once you get the arm on centre,
1. Are the front wheels pointed straight ahead, and,
2. Is the steering wheel on centre or cocked off a few degrees.

 

[HenrysT]

AusBucket, Looking at the pictures Buffman provided, the pitman arm nor draglink are installed yet. He will have to "clock" the steering box and the steering wheel once installed.

 

[AusBucket]

G'Day Henry, Didn't look at any pics, I was just replying to what was written. I'll try to get a look at what was put up. Thanks for the heads up.

 

[Buffman]

Thanks guys. Yes, nothing is hooked up yet except for the tie rod and steering arms on the hubs. This is a puzzler to me. I had a reputable shop install a new set of king pin bushings and everything on the disc brake conversion fits smooth. There isn't any binding when turning the wheel lt &rt by hand.

 

[choppedtop]

Usually I get wheels/tires straight and makes sure the steering box is in exactly half of travel position, then measure for correct drag link length. If it is to long, one side will hit stops and one side will not.

 

[PotvinGuy]

Well...it's 3" one way and 2.5" the other way. Not much difference. How are you sure the wheels are straight ahead when reading 21"? Being off just 1/4" at the steering arm could account for the discrepancy. And is the steering arm exactly 90 degrees to the wheels?

 

[Neshkoro]

There is an article somewhere on this site where it explained how to align your front end using string and a tape measure. It’s a bit involved but seems to work. Maybe one of the bucketeers knows where it is or where to find it.

 

[Indycars]

It was in the Tech Section of the NTBA website, I think you have to be a member to access. I've not read this article, but have used a version of the string method for alignment. I don't see how it's going to solve this problem, but maybe the NTBA article goes into more detail.

You are being redirected...
Front Tire Width and Diameter

 

[AusBucket]

G'Day Buffman,
Now I've seen the pics you put up, (Doh) I don't think there is much wrong with your setup. The hub needs to be able to turn out further than it can turn in to account for ackerman angles. The old wheel align guides back in the day gave an angle of 23 deg for the inside wheel when the outside wheel was turned @ 20 Deg. Have you tried measuring on the passenger side of the car to see if the difference is the same?

 

[Buffman]

Thxs Ausbucket, haven't tried that. I'll do that next and check for the angles to see how close they are.

 

[Buffman]

Still Haven't found the problem if there is one. Found my hair pins were out 1/4" shots on the driver's side, so have to take care of that.
Also does anyone know of someone/company that makes modified pitman arms for Vega steering boxes? I need one that is off set by 1 1/4" to 1 1/2" to clear the hair pin. The '37 Dodge pickup axle I'm using is wider than the Ford which puts the hair pin placement wider.
Always something you don't check first.

 

[Spanky]

Speedway makes one with a 2" offset. Can you make that work?

2 Inch Offset Vega Pitman Steering Arm, Tapered for Tie Rod, Polished (speedwaymotors.com)

 

[Buffman]

Thxs Spanky, I'll check it out.

 

[Buffman]

Turns out I already have a 2" offset arm. Guess I'll start looking for a 3" or try some machine shop cutting and welding.