BillaVista's steering Version 1

Dana44 Hy Clearance crossover steering - Ver. 1

After building my Hybrid front axle with D44 outers, including flat-top knuckles, it was time to design the steering.


Intro

This was my first attempt at the "Hy Steer crossover steering" setup on my Jeep. In the end, some parts worked, some needed redesign. I eventually went through 3 more setups before being satisfied. I have included all 4 setups so as to show what I learned along the way. This is the first setup, the next 3 are linked at the bottom of the page. Each successive page just shows the parts that were redesigned, so all 4 contain useful info.

Step one was to do the research. There is a ton of info available, and I searched out most of it. I have made a separate page with all of the results of my research, so that you may pursue your own solution. It contains information, theory, parts sources and specs, part numbers, pictures of links to others setups, links to companies making steering setups and more. It is focused on Dana44 front axle setups, but will be of interest to others in areas like linkage construction and TRE part numbers and specs. Check it out here:



One of the first decisions is whether to use rod ends (Heim joints) or TRE's (standard automotive tie rod ends). I chose rod ends because they are reasonably cheap, even for very good quality, available in many different size bearings with 3/4-16 threaded shanks (the weld in threaded bungs for the ends of the tubing are only available up to 3/4-16), and since they do not require a tapered mounting hole, it is far easier and cheaper to R&D different setups with rod ends.



The Rod Ends I chose are from QA1, | 21730 Hanover Avenue | Lakeville, Minnesota | 55044 | Toll-Free: 800.721.7761. I ordered them direct from the manufacturer. All the other hardware is from the Bicknell Racing Products catologue, ordered from my local race car supplier, R&D Performance center, RR#5, Truro, N.S. 1-800-565-3795.

These are the reasons I chose to use weld in threaded slugs (or bungs) instead of just buying the correct ID tube and having it tapped:

Using the threaded slugs might give you superior threads than having the local shop cut the threads in the end of the tubing, particularly if the slugs have the threads rolled and not cut. In fact, it is now not permissible to have cut threads on SAE rated fasteners. I'd at least want to see how the shop is going to cut the threads, especially in a 3' tube, and if they're just going to turn a big tap in the end by hand I might be worried. Not to mention there are pages and pages of references on different thread forms ( R type, J type etc.), radius at the root, pitch, profile, different classes of thread (2, 3, 5 etc. - not to be confused with grades of fastener (2, 5, 8 etc.)) etc and I'd want to be sure the male threads on the TRE or rod end were the same as those cut in the tube.

The rod ends and radius slugs I use are designed to work together. However, I'm probably overcomplicating the thread form concern (as usual) and they're all probably some sort of SAE standard, so this is likely not a big concern (other than the previously mentioned bit about SAE not allowing cut threads - I guess in the past some SAE bolts used to have cut, rather than rolled threads, and they were not as good.)

One more thought about slugs vs. tapping tube. Obviously tapping the tube you are limited to the alloy the tube is made from, and I'm not sure your standard low carbon 1020 DOM mild steel is the best thing for thread forms. On the other hand, the slugs can be made from an alloy better suited to thread forms, as long as it is weldable to the tube.



Essentially they are a tight slip in fit inside the tube about an inch, and the edge is beveled for the weld.



Also, note the "radius" after the main body and before the end, where the jam nut is. In terms of flow of stress and therefore fatigue life, this is a superior feature over just having the threaded tube end abruptly at the point where the threaded shank of the TRE or rod end enters. The abrupt change in diameter causes a concentration of stress and forms a weak point at this area, as the stress flowing along the tube has to "bunch up and get around the sharp 90* corner" formed at the abrupt change in radius. That's why I keep calling them "radius" slugs.



No matter how much research you do before hand, sometimes you just need to handle the parts. So I ordered 2 different styles of rod end from QA1. Thes are them and their specs. I paid $16.29 for EXMR 10-12 and $12.14 for CMR 10-12. The actual part numbers are:

CMR10-12T - Right hand thread
CML10-12T - Left hand thread
EXMR10-12 - Right hand thread
EXML10-12 - Left hand thread




After handling the, in my opinion, the EXMR are the superior part. And incidentally the same ones Rubicon Express use in their products.



We had a pretty good debate on the:



Slight typo on the pic label, it should read: "assuming a 3.5 FOOT draglink".


Misalignment of 17 degrees with the minimum 1/4" spacers.


Here are the "on the Jeep" testing shots.





Here's the pile of tubing I ordered for the linkages.



The weld in threaded slugs are made to fit in 1.25" x .095 wall tubing - light and strong for the race car builders. I wanted something a little beefier for trail use, so I ordered some 1.5" x .120 tube so sleeve over the other. That's a total of .215" thick - almost 1/4"!!





There's a ton of info on the research page about D44 steering arms, who makes them, how, why, etc. These are my home-made arms.



To make them I cut the shape from 1" thick steel. For the drivers side, I tacked the stock Chevy steering arm to the blank, and drilled the 3 holes. That was all that was required since the stock drivers side Chevy steering knuckle is already drilled and tapped. I retained the use of the 3 9/16 studs and added new hardened washers and ovalated locking nuts.



The passenger side was a bit more work. First the "flat" surface of the knuckle has to be machined flat. Then I tacked the arm on the knuckle, and drilled through both together with a 33/64 drill bit (the size required for tapping the knuckle). Then I knocked the arm off the knuckle, tapped the 3 holes in the knuckle with 9/16-NF tap, and drilled the holes in the arm out to 9/16" for the bolts. On this side I used Grade 8 SAE 9/16-NF bolts and hardened washers from Bowman.



Because I was not re-using the stock Chevy tapered hole and split conical washer system for positive zero tolerance location of the steering arm (an excellent design, but requiring more expensive machining and the rob-you-blind Chevy hardware [see research page]), I needed another method for assuring a tight positive fit that won't loosen, develop play, and place dangerous shear loads on the bolts. The bolts alone are not sufficient since, in order to be able to fit the bolt in and out of the hole, there is too great a clearance between the OD of the bolt and the ID of the hole. remeber, the bolts are not for locating, just clamping.



I decided on using locating dowels of hardened steel, pressed (pounded!) into slightly undersize holes for a tight fit.




The next pics show how the linkage all went together, and some of the things I wasn't happy with.



This is the drivers side. The hole for the tie rod was drilled the same distance from the center of the balljoint as the stock Chevy hole was. I used 2 tapered 1/2" steel spacers on either sides of the rod end, and a 5/8" Grade 8 bolt with oval locking nut. It's not a good design since the bolt is too long, and really the rod end should only be mounted in double-shear, especially with spacers on either side. As it is, the bolt is not a precise fit in the arm (no SAE bolt and drilled hole assembly is - precision fit for an assembly such as this can only be accomplished by drilling the hole undersize and reaming to final size, then using an appropriate precision bolt like an AN spec bolt), and the rod end will place bending loads on the bolt, which will fatigue and / or begin to wear the hole, leading to looseness and more wear in a vicious cycle until something fails. A proper "double shear" assembly would have the arm forming a "bracket" on either side of the rod end.



On the drivers side, I used the same two 1/2" steel spacers for the tie rod, and a 1.5" spacer underneath the drag link rod end and 1/2" spacer on top. This was required to space the drag link up enough to clear the tie rod (notice too that I could only build the tie rod out of the single thinner tube, or it would have been too large and interfered with the drag link). The result is an ungodly mess of spacers and improperly loaded bolts and just plain sucks from an engineering standpoint.



This is almost too embarrassing to show, but hopefully you can learn from my mistakes. I had to stack 2 spacers under the drag link to get the 1.5", one of which was aluminum and began to deform when the 5/8" bolt was torqued. Yeuch !! The drag link hole in the steering arm was drilled the same distance from the center of the balljoint as the end of the pitman arm is from the steering box output shaft - namely 6" in my case.



I had to bend the swaybar disconnect to clear the drag link, and the track bar axle mount used the old drivers upper control arm bracket on the axle. In the end, I removed the swaybar and trackbar altogether and do not regret it.



Another pretty gross setup. A 1" aluminum spacer on one side of the pitman arm rod end, and a 1/2" steel on the other. The automotive industry designed and uses TREs for a reason !!



The frame side trackbar bracket was the only bit that was sort of OK, nut I ended up junking it anyway.



Looks good if you didn't know any better !!


At least it was all up out of the way.



Well, it was all tucked up nice and safe, so that was something.



The problem was, even with the awful mess of spacers the drag link and tie rod still intefered.


This shows the problem


Summary:

A good start, but definitely not the complete solution. The use of rod ends is not the best, and the draglink and tie rod bind with any suspension movement.

On to Version 2.

Part Numbers:



Steering Index


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