Nuts, I’m Confused
Q I’ve been slowly building a ’67 Ford Bronco with a 31⁄2-inch Deaver spring lift, a 5.0L V-8, a 4R70W transmission, a Dana 20 transfer case, and full-width HP Dana 44 front and full-width 9-inch 31-spline rear axles. My question is about the steering setup. I’ve learned that it’s important to have the track bar and drag link as parallel to each other as possible (to reduce bumpsteer). What is a good angle to have the two links at when sitting at ride height?
My drag link and track bar are at a 15-degree angle when the Bronco is sitting at rest with full weight on it. Right now when the axle articulates it pulls to the driver side about 3 inches because of the angle and length of the two links, I assume. I can add a track bar drop bracket on the frame side and use a drop pitman arm to lower the drag link; this will make the links sit almost parallel to the ground at ride height. Even though it reduces the axle movement when flexing it also limits my bump travel.
A Your 15 degrees looks pretty steep to me. I assume a bumper (possibly with winch) could reduce the angle some more as the springs settle, but getting the track bar to be closer to level at ride height is important. On a front suspension with a track bar I like the track bar long, level, as well as parallel and close in length to the draglink.
Some suspensions are set up where the track bar is level at ride height, some are set to be level at full compression, and both have pros and cons. A track bar that is level at ride height will have the axle moving toward the driver side as it compresses and also toward the driver side as it droops from ride height. This means the axle changes direction through its arc of travel. A track bar that is level at full compression will always be moving the axle in the same direction from full droop to full compression. Both will have their own unique driving characteristics, but the majority of suspensions have the track bar level at full compression. Most of the trucks I have owned or worked on with a track bar run about 6-10 degrees at ride height and are 35-40 inches long, but these trucks all sit fairly low.
You could add a crossover steering setup and have the drag link attach to a high-steer arm on the passenger side of the Dana 44. This may require a special flattop knuckle or having your knuckle drilled and tapped for a high-steer arm, but it will raise the drag link and you can then raise the axle end of the track bar to match the angle. You can even mount the track bar onto the Axle “C” itself, as they are weldable. Dropping the track bar mount a bit may not be bad either as well as moving the mounts to the outside of the framerail. A drop pitman arm on a Bronco box with the already long sector shaft is slightly concerning because you are adding a fair bit of leverage on the sector shaft. If you move one part you need to watch for clearance issues at full range of travel and articulation, and throughout the steering motion to ensure that parts don’t crash into one another.
To get overly complex, you could add a swing set on the passenger side for the steering drag link to attach to, and then have it come back and attach to the driver-side steering knuckle. This would allow you to mount your track bar considerably lower on the passenger-side framerail, but it also complicates the steering ratios (see photo).
The problems occur when you try to make everything perfect and simple; sometimes it just won’t work. If you get the track bar flat at full stuff it may hit the passenger framerail (I’ve seen framerails notched to allow full compression). If not, the tires may hit the fenders. It’s OK if the track bar is slightly longer, shorter, or at different angles than the drag link, but the less difference the better. A track bar with a bend in it is also a possibility, but I am less thrilled about this option due to the strength loss. There are, however, some very good forged track bars with bends in them to clear differentials and framerails from the factory. The current Ram truck version and the ’79 Ford F-150 are both options I like, though you may need to shorten them to fit your application, or move the track bar mounts. A straight track bar is usually stronger than a curved bar, but the angle of the track bar is dictated by a straight line through the two mounting points, not the angle of the bar if it is bent. In the end you may need to make some sacrifices here or there to get it as close to level, long, parallel, and even in length as possible.
I hope this helps you instead of opening a larger can of worms. The setup you have will work, but it could work better. Your question is common to a lot of readers looking to build their own suspensions, so I’m awarding you the Nuts, I’m Confused letter of the month.
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