Ok, I've basically got this thing steering- and quite effortlessly, I might add. When my wheels are cut completely to the left (sitting in driver's seat), everything clears great. See pics....
However, when I cut them all the way to the right (sitting in seat), I only have about an 1/8" of clearence between the drag link and the wishbone. When I jump up and down on the front end, they actually hit. If I bend the pitman arm in more towards the engine, I have strained the range my tie rod end can flex (make sense??). I could bend my hair pin steering back up but wanted to keep it low (like the Bishop Tardell books states) to help keep it parallel with the wishbone....even though it's not perfect now.... Any suggestions? I know my brake hose on the left is tight when cut all the way. Really, it's not as tight as it looks.....
Looks a lot like mine. Even with the steering arm bent down, you will still get a little bumpsteer. No big deal, though. Who took a torch to the spring? That looks a little scary. Rich
first off, what is the layback of the axle with the wishbones how you have them? they look like they are mounted high on the frame to me? layback on the axle should be around 7 degrees. for correct ackerman (no bumpsteer) the line drawn from the steering arm to the drag link should intersect with the mounting point for the wishbones
I posted before I saw your second post. Mine was much worse because I am running suicide with the axle moved forward about a foot. I know others will not like the idea, but I bent my drag link in an "S" shape to clear the wishbone better. Rich
here's some possible fixes; 1, Shim the steering box so that it sits closer to the frame. The above may require flipping the pitman arm or finding a straight one. 2, Bend the steering rod to clear the radius arm. the above also solves bumpsteer problems. YOu may potentially need to flip the pitman arm over for this as well. 3, Increase the length of the steering arm. 4, Build new radius arm mounts that locate the radius arm farther away from the frame.
REV- I have 5-7 degrees built in.... Rodster......yep, we crossed wires.... Steevil- that looks like it works.......don't kick me or anything but how does it drive? does it do anything to your geometry? looks like you built it heavily....
Got it!!! I shimmed the steering box over about 1/2" with nuts as spacers. I bent the steering arm in some more (may not have had to do that). I used my adjustment in the drag link to help some too. And, when I heated the smaller end of the pitman arm, I gave it a slight twist to help take out the bind that it put the tie rod end into. You know, it would have been much easier to bought a 35/36 coupe, etc. and not had to engineer all of this. But you know what, I wouldn't have learned squat!!! By mixing and matching parts. By engineering most of this roadster, I have learned a ton! All of this, thanks to the the thing that is, the HAMB. .....you cannot touch it. It is like a breath of freesh air in the morning near a lake with swans swimming.....hahahaha I'll quit.....wasn't there a Saturday night live skit similar to that.....
This is a GREAT thread, I'm in the same boat, trying to fit my spilt bones around my drag link; I'm running my Model A box and A bones, and that is one LOOONG pitman arm. You fellas are posting some great methods and pictures, keep 'em coming! How important is it to keep the drag link parallel and about the same length of the bones? I'm gonna hang my spring right below the bones (make a bracket that hangs just below the bottom of the bone, I got a design in my head that will distribute the weight on the bone well), and gonna pull my front axle out forward a bit so I can run my flathead/3spd?/torque tube and position the engine/trans so I don't have to cut down the driveshaft. Thanks guys, like I said this is a great thread.
Well I thought that I would stay off this for a while for fear that it would be interperted as being overly critical but I have to post in before you do a lot of work for little gain. There is nothing wrong with you idea that a liitle reevaluating can't cure. Since I am just looking at a few pictures that may be somewhat out of proportion, this is just a few thoughts on what you are building and issues I think need to be addressed. Lets start with the easiest. The flex brake lines are too short, Wagner makes a brake hose that is longer that cures the tight lenght on Model A. Go to the parts store and ask to see the Wagner spec book with pictures, since some hoses are 3/16" you should not mix with 1/4" line check (f25629). Yes, you can turn one way easier than the other due to the Ackerman principle everyone talks about. It is important in the aspect of proper wheel track as a vehicle revolves thru the cornering mode. Back yard mechanics rule is to check that the center line of the tie rod arm end aligns with an imaginary line drawn from the center of the king pin to the center of the rear axle housing, in most cases the center of the pumpkin. If it doesnt you have an issue. Your limited turning is due to a number of measurements that relate to the drop of the axle and the perch pin to king pin center distance and then again to the perch pin spacing on the axle. These all vary based upon choice of axle. A view of yours appears that this axle has positioned the wishbone split at a shallow angle. This shallow angle causes the tires to contact the wishbone or come very close at lock turn. Under no cir***stances should the tires come into contact with any part of the car before the king pin stop halts the rotation of the spindle. It appears that due to the long length of the wishbone that you may wish to mount them more inboard and increase the angle to allow more steering rotation. Next is addressing the pitman arm situation. This baby looks way to short to be correct. Back yard mechanic rule is that the pitman arm used with stock box should be approximately the same length as the steering arm on the spindle or around a 1-1 ratio. To far above or below that ratio causes some exciting steering situations. Because of the choice of steering box and angle of drag link there is not much you can do to eliminate a slight bump steer problem. With the addition of a panard rod and stiffening the front suspension to limit the ch***is up and down travel you may be able to contol this but sacrafice to a hard choppy ride. It is this ch***is travel that exagerates the bump steer and makes driving a chore. I am not in favor of z fabing steering components as this produces a flex point at the bends and requires a gusset, without one a slight stressed bending during operation actually metal fatigues the componet making it unsafe especially in mild steel. The problem with building picture period cars is that alot of these cars drove like **** but no one admitted to it. There were a limited number of parts suppliers that even wanted to address the hot rod fad segment so you used what you could get and that was good enough. Today there are wider options but not as period correct but mabey easier and safer to drive. In any case your idea doesn't look all bad just need a tuning so just use this info as it is, informational. Keep on working on you project as I think it will be safe to say it will probably be the first one built on the internet school of hot rodding. ****.
Works great except the 57 F-100 box is a bit sloppy. No bumpsteer at all. The only thing I would change would be to get dropped steering arms and trade the bent tie-rod for a straight one. The tie-rod is bent to clear the engine and does allow for a bit of flex.
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