Funny, in 2015 at Goodguys in Puyallup, WA we were looking at the "Deuce Doin's" corral and I was talking to several owners who had built their own cars about their front end setup. I had just bought my A and had never done a dropped axle before. They all had caster in the standard range of 5-7°, then I talked to the guy with the car pictured below. 13 degrees! He said "Yeah it's a little hard to steer at slow speeds, but it's really stable and handles great at higher speeds." I guess it all depends what characteristics you're looking for, but that was as extreme a number as I've heard.
I'm glad you noticed a large difference. Are you running cross steering, and does your rear panhard go the opposite way? It sounds like you put your panhard the wrong way (attached to the frame and axle on the wrong sides). The idea is to match your steering direction so they're not working against each other.
I'm sure it's better BUT . . . You've got it backwards, the panhard bar should mount to the chassis on the same side as the steering box (drivers side) and attach to the axle on the passenger side. It makes a difference.
It May be "backwards" but it works and it works great. I layed under the car for an hour with a piece of three foot wood dowl. I put the panhard bar in the only place I could put it. As the car is already finished, I'm not pulling it apart to add the bar. And with the big Pontiac motor there is simply no room. I took it for a good long drive yesterday. Twisty highway at speed. It drives great. In happy. My next one I'll put on the "correct" way. But for this build, I'm happy . Thanks again for all the input.
Along with the correct orientation pointed out by 05nopro440 and Pete Eastwood, it should also be parallel to the ground at ride height. As the suspension cycles up/down the length of the rod changes, you want to start with it at the maximum length at ride height.
It is a cross steer, Vega style box. While not parallel to the ground or the drag link (it's close) it is 30" long. With 3" of suspension travel I don't see the "arc" really coming in to play.
Without pictures we just have to take your word for it, but I'm curious about the explanation that there's only room to put it on the one way. The bar takes up the same space either way, so why couldn't you do it the opposite way?
The problem is on the driver side of the frame there is nowhere to make a mount for the bar. Between the shock mount, and the steering box set up. It wasn't feasible since the car is already built and driving. I could have done it farther back, behind the steering box. But that would be halfway back and really not as effective in my opinion. As it is now it is at the very front of the bone. Straight across to the frame on the other side. Backwards or not. It works great and I'm happy.
@alchemy Help me understand this. I pulled the front end out of a '40. Cross steer. I'm using that setup on the front of my A chassis. It seems like the identical setup to the '40. Do I still need a panhard even though the '40 didn't have one? Why? Not questioning you, just trying to understand.
I will condition my response by saying I am not a chassis builder or an engineer, what I know I have gained by listening to those that do know and emulating them. A: If it aint broke...You don't have a problem, maybe don't go looking for a fix. B: Any car with a transverse front spring and active shackles would benefit from a Panhard rod, or a dead perch on one side, or that cool ass tuning fork pictured above (I really like that idea). The shackles allow the car to sway side to side like a pendulum, which can be an issue. Parallel front springs prevent that side to side motion, as do all of the fixes mentioned. It is all about locating the chassis over the suspension and keeping it there. That is over simplified but the way it was explained to me by my chassis builder. I have even heard that tube shocks help stabilize a front end.
We never did get a straight on front end pic from op to see his shackle angle as requested by others posting.
True that, and one thing I left out is the angle of those shackles help stabilize the front end. Worse would be straight up and down (which isn't really possible but illustrates the point) of a pendulum swinging back and forth. But rather than I hunk of polished brass it is the axle.
I had a similar issue I found that my panhard bar was slightly loose, but enough to make the car wonder. Snugged up the bar and the car drives like a dream. It took me over a year to find the issue. Visually everything was there and CORRECT. I only mention this for the next guy searching for help.
I think the original wishbone has a lot of responsibility in keeping the axle from pushing side to side too much. Coupled with shackles at the proper 45 degree angle. Ford used the system on the T’s, and then from 35-40 with no panhard bar. But in 40 they improved the system on the deluxes with the sway bar, and it had much tighter links to the axle than modern sway bars. So I think Ford knew it could use some help, and finally found the way. In another year they developed their panhard bar on the front, and then in another couple years put one on the rear as well. Shows that the system was always changing for the better.
Thanks @Bandit Billy and @alchemy That helps me understand. Looks like I need to add a panhard bar. Couldn’t hurt.
On my roadster I had painted the frame and was re-assembling when I realized I forgot to weld on the Panhard bar attachment point. Bonehead! I ended up building my own mount, chromed it (duh) and bolted it to the boxed frame rail. Worked out great and has been on there for years. But if I had it to do over, I would probably do that "tuning fork" idea. Very un-invasive, bolt on, simple fix that locks that axle down.
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