It was brought to my attention yesterday that my pitman arm and drag link may be at to much of an angle. If i were to flip the pitman arm, it will hit my firewall when i turn....I had to move everything back do to the stock manifolds for the ford 400 engine exhaust manifold.....You all have any thoughts on what i should do here? Is the current angle okay, or should i try to cut into my firewall and flip the pitman arm?
Pitman Arm and drag link location
- Thread starter hotwheels
- Start date
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Blue Eyed Devil
Devil's Advocate
In the current configuration you are going to get some serious bump steer. It should really be more parallel with the hairpins. You can't just flip the pitman arm. It will steer backwards, like a boat.
You could wait until you drive it once - low speed into some chuck holes or across a RR track. Maybe even grab the steering wheel while a fat friend jumps on the front end?
Your probably gonna get bump steer though and you don't wanna find out it's worse than you thought at 60mph. I'd probably go ahead and plan on cutting the firewall - safety first. Might as well get it right now.
Your probably gonna get bump steer though and you don't wanna find out it's worse than you thought at 60mph. I'd probably go ahead and plan on cutting the firewall - safety first. Might as well get it right now.
King Herald
Well-known member
No, it doesn't want to be parallel to the hairpins.
You need to look at the radii your various joints will move through, where the drag link meets the front suspension etc.
Having the drag link parallel to the hairpins is about the worst way to do it.
1 and 2 are good, 3 is terrible, 4 is best.
Blue Eyed Devil
Devil's Advocate
No, it doesn't want to be parallel to the hairpins.
1 and 2 are good, 3 is terrible, 4 is best.
I said MORE parallel, not exactly parallel. I was referring to something similar to the stock Ford geometry, like in the #1 diagram.
What is shown in the picture of the truck resembles the #2 diagram. It is NOT good, and it is going to result in bump steer & handling issues.
bob w
Still crazy after all these years!
http://ratrodsrule.com/forum/showthread.php?t=3655
The diagram in the above thread matches DMW56's build and also is the way I built my '27 Chrysler Tub. It has no bump steer either.
The diagram in the above thread matches DMW56's build and also is the way I built my '27 Chrysler Tub. It has no bump steer either.
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dmw56
Busted and Rusted on Route 66
Yours looks like it's exactly where it should be. Does not need to be parallel except on 4 bar with a mustang box.
Angle does not matter. If you draw a line from your steering arm through the point where the drag link connects to the pitman arm it should intersect the rear mounting point of your wishbone or hairpin. Does not matter if the box is in front or behind the hairpin/wishbone attachment point.
You shouldn't have any bump steer or steering issues at all.
Here's a pic of mine never had a bit of bump steer. Straight and smooth at over 70-80mph.
Angle does not matter. If you draw a line from your steering arm through the point where the drag link connects to the pitman arm it should intersect the rear mounting point of your wishbone or hairpin. Does not matter if the box is in front or behind the hairpin/wishbone attachment point.
You shouldn't have any bump steer or steering issues at all.
Here's a pic of mine never had a bit of bump steer. Straight and smooth at over 70-80mph.
donsrods
Well-known member
Unless I am missing something in the very first picture at the top of the thread, his drag link is exactly where it should be. It intersects the point where the radius rod bolts to the frame, so the drag link will arc the same as the radius rod.
In the real hot rod building world, it is very hard to get things to end up as they appear in drawings and magazine articles. For example, on my 27 the steering arm ended up out of the spot that should give good handling, but the car goes right down the road at all speeds, hits bumps, etc, and never do I feel a twitch at the wheel. It is nice to get as close to "correct" alignment as possible, but there are a zillion cars running around sucessfully with stuff on them that "shouldn't work". We never know until we take them out on the road and see what issues we have to work through.
Don
In the real hot rod building world, it is very hard to get things to end up as they appear in drawings and magazine articles. For example, on my 27 the steering arm ended up out of the spot that should give good handling, but the car goes right down the road at all speeds, hits bumps, etc, and never do I feel a twitch at the wheel. It is nice to get as close to "correct" alignment as possible, but there are a zillion cars running around sucessfully with stuff on them that "shouldn't work". We never know until we take them out on the road and see what issues we have to work through.
Don
Blue Eyed Devil
Devil's Advocate
Agreed... [ddev
hotrod preacher
"Official RRR Chaplain"
since the bump-steer discussion is settled, i would recommend jacking up one side and turning your wheels from "lock-to-lock" to make sure everything has clearance when the suspension is "working" ....
cool looking ride too BTW
cool looking ride too BTW
Your pitman should be perpendicular to the drag link. (from BobW's thread)
I remember reading that thread. How quick I forgot!
I remember reading that thread. How quick I forgot!
moparcowboy
Well-known member
I would also drive it first but looks scary to me.
donsrods
Well-known member
Like I said, I must be missing something some of you are seeing. If you draw a straight line from the steering arm on his wheel to the steering arm on the box, you will see where it intersects the place where the wishbone bolts to the frame. So the draglink and radius rod will move in almost the same arc.
As for the draglink needing to be perpendicular to the steering arm, I respectfully disagree. Look at the picture below. It is the only good shot I have of my steering arm on my 27 (under the sheets behind the mocked up body) look how my draglink is not perpendicular to the steering arm, and when the weight of the engine and transmission are on there it is even further off. Yet, in the 20 odd years I have had this car it NEVER has had any bump steer issues whatsoever, and the car has a ton of miles on it during those years.
I think sometimes we get too hung up on what the magazine experts say. Take a look at all the cars the next time you are at a show, you will see lots of cars with draglinks running on angles odd to the ones suggested, and I bet most of those cars handle pretty well. This is one of those subjects where there are no correct answers sometimes, and no winners in the discussion.
Don
As for the draglink needing to be perpendicular to the steering arm, I respectfully disagree. Look at the picture below. It is the only good shot I have of my steering arm on my 27 (under the sheets behind the mocked up body) look how my draglink is not perpendicular to the steering arm, and when the weight of the engine and transmission are on there it is even further off. Yet, in the 20 odd years I have had this car it NEVER has had any bump steer issues whatsoever, and the car has a ton of miles on it during those years.
I think sometimes we get too hung up on what the magazine experts say. Take a look at all the cars the next time you are at a show, you will see lots of cars with draglinks running on angles odd to the ones suggested, and I bet most of those cars handle pretty well. This is one of those subjects where there are no correct answers sometimes, and no winners in the discussion.
Don
Well, I for one was dead wrong. Bought in to the myth that the drag link needs to parallel the bones.
As for the perpendicular thing, I don't think that's a bump steer issue, I'm thinking it'll just cause the turn ration to be quicker one direction over the other. Maybe a non-issue...
Exactly my thoughts......
King Herald
Well-known member
Is it just me or is everybody seeing a tiny postage stamp piccie?
I can't really make out where the drag link is, just assumed it would be in the usual wrong place, like you see in so many 'offbeat' rod magazines.
ETA: Ha, just did some detective work and found this pic. Yes, that drag link is in just about perfect position. They do look a bit odd like that, but the best handling is to be found that way.
I can't really make out where the drag link is, just assumed it would be in the usual wrong place, like you see in so many 'offbeat' rod magazines.
ETA: Ha, just did some detective work and found this pic. Yes, that drag link is in just about perfect position. They do look a bit odd like that, but the best handling is to be found that way.
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