A hi-steer conversion is intimidating for a lot of people because there are many ways to do it wrong and it requires some quality machining work which many fourwheelers cannot do themselves. I'm one of them. Nevertheless, I had to switch Project YJ to a hi-steer setup. In this article, I'll tell you what a hi-steer setup is, and why it's a good thing to have.
The simplest hi-steer setup moves the location where your drag link attaches to the knuckle to a higher location, thereby making its angle close to horizontal. A full hi-steer setup moves the tie rod higher, as well. That's all there is to it. So, why is hi-steer good? There are two main answers:
- A hi-steer system is an excellent way to eliminate bump steer on a leaf-sprung suspension.
- Moving the drag link and tie rod higher protects them from damage from rocks and stumps.
What is bump steer? Bump steer is the steering effect you get when your front suspension compresses and results in the front wheels being steered in one direction or the other. Bump steer in leaf-sprung vehicles occurs when you have a drag link angle too far from horizontal. The reason for this is because the drag link operates in an arc, which has the pitman arm connection as its centre point. When the angle is close to horizontal, any vertical movement (caused by the suspension flex) of the drag link results in very little side-to-side movement. But the greater the drag link's angle, the greater the resulting side-to-side movement. This side-to-side movement of the drag link applies a force to the steering arm on the knuckle. In other words, it becomes steering input to the wheels. Hmm...maybe we need a diagram.
Ok, in the above diagram, red represents a horizontal drag link and green represents a non-horizontal drag link. In each, they have been moved the same amount vertically. As you can see, for the same amount of VERTICAL movement, the horizontal drag link has resulted in much less HORIZONTAL movement than with the non-horizontal drag link. It is that extra horizontal movement that is the cause of bump steer. Making the drag link horizontal is a way to eliminate bump steer...IF you have a leaf-sprung vehicle, or a suspension that doesn't rely solely on a track bar to horizontally locate the axle.
If you have a coil suspension like on an Early Bronco or a Jeep TJ, simply making your drag link angle horizontal isn't going to eliminate bump steer. Why? Because with a leaf sprung suspension, we assume that the axle moves up and down with virtually no side-to-side motion. Thus, bump steer is the drag link's side-to-side movement conflicting with the otherwise laterally stable axle. With a TJ suspension, the track bar locates the axle laterally, and that bar also operates in an arc, just like the drag link. So, with the TJ, you don't really care about the drag link being horizontal. What you really care about is making the track bar and drag link angles parallel to each other. This way, the horizontal movement of the drag link will be virtually identical to the axle's movement, which means that there is no steering input (ie: bump steer).
So, even though a hi-steer setup isn't a cure for bump steer on coil-sprung vehicles, it is still a great way to protect steering linkages.
Now that we know the reason I wanted a hi-steer system, I'll tell you how I did it. I decided to build a system similar to factory YJ steering linkage, which is commonly referred to as an inverted-T design. Basically, the drag link connects to one end of the tie rod. Envisioning this is easy, it's collecting the right parts and doing the machining to make everything work together that is the hard part.
- 1 x ES2027L GM drag link end
- 2 x ES2234R GM tie rod end
- 1 x ES2233L GM tie rod end
- 1 x 14024806 GM Jam Nut
- 1 x 14024805 GM Jam Nut
- 1.25 0.219 DOM (approx 6 feet)
- 2 x flat top knuckles
- 6 x 9/16-18 studs (GM 3965137) - for the knuckles
- 6 x tapered cone washers (GM 3965138) - for the knuckles
- 6 x jam nuts (GM 9442950) - for the knuckles
You can buy all the parts at your local auto parts store, and the DOM tube from a metal supply shop. Hi-steer arms can be purchased from any off-road shop and lots of places on-line. The flat top knuckles will require some scrounging. The most common source for Dana 44 flat top knuckles is from GM trucks. Other sources includes Jeep Wagoneers and some Dodge trucks. One of the rarest sources is some full-size International Harvester trucks. I lucked out and found a set so I could re-use my existing IH Scout spindles, hubs, bearings, etc. Had I not been able to find any IH knuckles, I would have had to convert to GM parts which isn't such a bad idea but I was in a hurry and this was the cheaper route, too.
Visiting Your Local Machinist
Before you run off to your local machine shops with the parts, there are a couple of things you need to do. First, place the various tie rod and drag link ends in their respect positions to get an idea of the length of the tie rod and drag link you'll need. Here's how the parts will attach to your Jeep:
Cut the DOM into two lengths. One for the tie rod end and one for the drag link. Also remove the pitman arm from your Jeep. For Project YJ, I used a stock pitman arm. If you're running much more than 6" of lift, you may need a dropped pitman arm. And now you're ready to head to the machinist's. Here's what you need done:
- ES2233L - passenger side tie rod end, joins the steering arm and tie rod.
- ES2234R - driver side tie rod end, joins the steering arm and tie rod.
- ES2027L - high angle drag link end, joins the drag link and pitman arm.
- ES2234R - tie rod end, joins the drag link to ES2233L on the passenger side of the tie rod.
- The flat top knuckles need to have their surfaces milled. The passenger side knuckle needs to have holes drilled and threaded to match the driver side (9/16-18).
- The tie rod end (ES2233L) needs to have the hole in its shank (originally designed for mounting a steering damper) tapered from the other direction. The taper is 1.5 inches/foot. The tie rod end, ES2234R, will fit into this newly tapered hole. Test the fit frequently so you know when you've got enough thread engagement and enough clearance for the grease cup.
- Both steering arms need to be drilled/tapered to accept the GM tie rod ends. Again, they use a taper of 1.5"/foot. You can use tie rod end ES2233L to test fit the hole. You want to make sure you've got enough thread engagement and clearance for the grease cup.
- Have the drag link end of the pitman arm reamed out using the 1.5"/foot taper. Test for a proper sized hole by using drag link end ES2027L.
- Have the drag link and tie rod tubes drilled out for 7/8-18 threads. Make sure one end gets a right-hand thread and the other gets a left-hand thread!
With all your parts in hand, you can now scurry home to begin disassembling your old suspension and installing the new parts. If you're going to do this project yourself, you already know how to do this so I'm not going to get into the sordid details. Don't forget to get your alignment checked, once you're done. And triple check to make sure all the nuts are tight and the kotter pins are in place!
The very hard-to-find IH flat-top knuckle (bottom right).
Cutting threads into the DOM by hand (the lathe was just used to hold the tube in place) was a major PITA. I strongly, strongly recommend getting a machinist to do it for you!
Here's where the parts were installed. This is a view of the passenger side knuckle.
And here's a view of the drag link and driver side knuckle.
If you've done it right, you'll have a before and after view that looks like this. Notice the awesome ground clearance that will make it extremely difficult to damage your steering linkages. Also notice how much thicker the tubes are compared to the stock YJ pieces. And finally, look at the drag link angle. It's almost perfectly horizontal.
A Thousand Thanks To...
- Glen Hogenson for finding me a very rare 53/64" drill bit and helping me do the install at a time when I was frantically trying to get my Jeep ready for Rock Crawl!
- Chris Siebert for lending me his 7/8-18 left- and right-hand taps.
- Jon Bruce for lending me his reamer.
- Richard Sikich for doing the machine work. Check out his website: westecequipment.com
- "Billavista" for his absolutely indispensable compilation of Dana steering information which you MUST read at this website.