The Stovebolt Site Forums The Shop Area Driveline Steering arm and drag link upgrade

I know I have seen them, but can’t find any info at the moment. So does anybody have a link, part numbers and or additional information on how to do this upgrade. I want to get away from the stock ball and socket set up. The steering link set up in picture is from a 51 Chevy 1ton and is what I am working with.. Thanks..joe

Joe, I did a little searching through Stovebolt and came across this thread specifically on your topic. Fellow Bolter WICruiser seems to have had a custom replacement adjustable tie rod end style link made relatively inexpensively for his 3600 that may fit your desired results. Parts books indicate the steering arms and related components for the 3600 will also work for your 3800 (3100 are a different size so the Legacy Tech Tip for 3100's won't give your the correct parts needed). The pictured link in the mentioned thread looks plenty strong and also allows for adjustability to get your steering just right.

Perhaps WICruiser will reply here to provide a bit more detail on the specifics of the link he had made?

Joe one of the parts that was commonly used to make an adjustable drag link has been discontinued for over 15 years now. I found a genuine MOOG part, used it and it failed spectacularly in about a year...not anything I would want to happen to anyone. I went back to the original drag link, got new balls, rebuilt the link parts and am very happy with it. Just FYI. I used the balls that attach with threaded posts and nuts. Every year I loosen and rotate them 90 degrees so they don't wear egg-shaped. As for the tie rod ends, you can find replacements with the new style from many suppliers and those seem okay to me. At least mine are still fine.

I know you didn't ask for opinions but, I'm very happy with the stock components after rebuilding the drag link and tie-rod ends. Along with new king pins and bushing it drives great with radial tires. 1951 3600.

RonR

Thanks guys, and Ron nothing wrong with opinions. Especially since it becomes knowledge. And that being said, I guess I’ll see what it takes to rebuild my stock stuff….. thanks again,joe

Gdads51 mentioned my modified drag link setup but in my case the modification was required because the steering box was moved out almost 2" to provide clearance for my SBC exhaust manifold. As a result I wanted to have the drag link attached to the inside of the pitman arm rather than the normal outside location.

The parts I used are a combination of heavy-duty rod ends and a custom made link. I can provide more details if anyone is interested in this approach but if standard geometry is required I don't know that there is a need to create a better design than the original.

I finally found images of the adjustable drag link I made. The one which failed...dangerously I will add. Fortunately I was just pulling away from a stop when it did. It seemed like a good idea but in my case it wasn't. Good luck!

Jon, what part failed? Did you re-install the original drag link?

There were two tie rod ends used to make this drag link. One was for that very large Jeep Wagoneer made in the late 70s and early 80s. The other was a commonly available part used in many GM vehicles. The tie rod end used in the Wagoneer failed completely...and by that I mean it appeared the insides broke first (nylon/plastic parts had been used in the manufacture of it) and after that it just all came apart. Talking to the MOOG folks it was a part which they had not made in over a decade, it was used in a different application than it was designed for and the bottom line was they were sorry, they were glad nobody was hurt and past that there wasn't anything they could do. Since it was a discontinued part they couldn't replace it. Yes, I installed new balls and rebuilt the original drag link. Actually it wasn't original to the truck but a replacement link I had bought new in 1977...a GM part, though. Somewhere I saved that Wagoneer tie rod end and when I run across it, I'll post a picture.

You and others may already know this. The drag link in the AD truck ought to sit parallel to the ground but it doesn't. Many shop manuals show this incorrect orientation, also. This does contribute to bump steer. The only way to remedy this is to remove spring leaves to the point where the truck sits about 1.25 inches lower but that can cause bottoming and other problems. It can cause your caster angle to become variable for one thing. Over the years I've run across drag links used in AD trucks which were bent...bent so that it "seems" the drag link works on a more level plane, but honestly it doesn't. They were bent so that the part of the drag link which connects to the control arm seems level. You can see a picture of the two types below. You can also see a little picture I made showing why having the drag link's pivot point further down on the arc of the circle will worsen bump steer...the further the pivot point is from dead level (the red oval) the more a little movement will cause a greater movement in the drag link because of simple geometry. Especially if it moves downward. Only at the center will bump steer be at its least.

Something I’d like to try but doubt I ever get around to:

Theoretical recipe for adjustable AD drag link:

* The ubiquitous and cheap Ford 11/16 tie rod ends in both LH and RH threads.

* Section of threaded tube from someone like Speedway.

* 7 degree taper tie rod reamer. (Might have as much money in this as you do the others parts combined)

It would take just a little more research to verify this would actually work. I believe there is enough meat in the steering arm. Definitely enough meat in the pitman arm. The thing that MIGHT make this harder than I think….is if either existing hole (once ball studs are removed) is too large at the small end for the taper of the Ford tie rod. A machine shop could always press a bushing so that it COULD be reamed to the right dimension.

(I ended up converting my 51 to the 53-55.1 drag link. Not because it was ideal, I just had the part to make it work)

JW51,
Just as you are suggesting, a few years ago I used the Speedway 11/16 Inch Raw Tie Rod/Drag Link Tubing and used male L&R ford rod ends , that way i just bought the RH tap & cut/tapped for a adj drag link. There was just enough meat for a race shop to taper ream the steering and pitman arms. It is holding up well.
BTW: when i thread tapped inside the cut end i started with rod 1" longer than i needed, even using a proper tapping fluid, it turned out a good move as the first bit of the tap process (finding straight) alignment left those first threads looser that desired, had the 1" to trim off so threads were a good snug fit, ie: dont tap too deep........
In reality you don’t get much adjustment as you want a lot of thread overlap inside the rod.
The one downside to the speedway rod is that there is no ideal way/place to put a wrench on it to tighten the jam nuts (to keep both ends aligned). Thought about welding a drilled out nut over the end to wrench on but did not.

Chuck

Where does a guy get the springs for the drag link internals?

The ones I got in a kit for my 1-ton from Jim Carter were listed for the 1-ton but the springs are no where near moxie enough to do the job. One of my originals broke and I had to use one of the little springs from the kit and juggle springs around to get the effective length of the Drag Link correct so the steering wheel would be straight. When those springs get weak or broken the steering gets unnervingly vague. My DL's balls are welded in.

Regarding bump steer, there is an argument to be made for keeping the factory setup. On my 51 the drag link is parallel to the ground when the truck is loaded with 3,000 lbs. on the ft. axle, which is most of the time. The springs in the drag link take up some of the shock form what bump steer does occur. I have long wondered why GM kept the old style on the drag link but went to modern units for the tie rods. Maybe that's why but I suspect it was for cost reasons and to reduce maintenance.

These trucks were engineered to carry a load. It doesn't surprise me that the drag link is only parallel to the ground when there is a load on the truck.
If they had designed for the drag link to be level unloaded, what would be the unintended consequences of the drag link being unparallel in the opposite direction when the truck was fully loaded? I am guessing bump steer.
I know one thing, I'd rather deal with a little bit of bump steer with an empty bed than any bump steer at all when fully loaded.

Well, my experience with the 1/2 ton trucks is that if I load 800 to 1000 pounds in the bed, it causes the rear springs to compress about 1 inch at rest and bumps in the road will cause the pads to hit the frame but that extra weight will not cause the front end springs to compress correspondingly. In fact depending on where the weight is, it can cause the front end to lift up due to weight shift and that will cause the steering to seem to float at any speed over about 40 mph...the exception is if I can load all the weight up near the front part of the bed to put it mid-ship. That centralizes the load and minimizes the front end float somewhat. With firewood, dirt, gravel you can't do that, however. The last time I had to haul a complete engine and transmission, the yard loaded it right at the back of the bed and driving home was a real challenge. Same with a front clip for an MG-B. I had to carry one of those to a town 70 miles away and steering was a mess.

Whether the drag link is above or below the line of being level doesn't matter...especially for a front end designed like the AD. If we had a track rod or track bar that was a different length than the drag link then we could have all sorts of different bump steer problems. Those have different pivot points and thus different arcs and all sorts of "arguments" can happen. Our front end works more like a simple 4x4. We just have a solid axle, a tie rod and a drag link so the drag link makes the arc. To minimize bump steer the drag link has to hit the center (parallel). You can see it...very easy to visualize. The higher point on the arc of the circle will have the same effect as the lower point and the higher/lower on that arc the point of intersection is, the more bump steer will occur because just a little movement will pull/push the drag link in an exaggerated manner.

Also remember that when changing wheel diameter and/or offset, it can do funny things to steering geometry and handling. Since a lot of these old trucks become "Cowboy Cadillacs" that seldom if ever carry anything heavier than an iced-down Yet cooler to a tailgate party, the steering problems don't really show up until somebody decides to haul a full GVW load somewhere.
Jerry

With the spring anchored to the frame at the rear, the steering knuckle will travel in an arc whose center it at the spring anchor point, an arc modified by the fact that the other end of the spring is anchored by the spring shackle but it will travel in some form of an arc nonetheless. I expect that when GM engineers designed the front suspension they chose spring lengths and center points so that the arc of the knuckle would match the arc of the drag link as closely as possible. That would minimize bump steer. Of course the arcs cannot be identical because the pitman arm center is a foot or so above the spring anchor and forward of it.

I note that some old heavier GMC trucks had the fixed point at the front and the shackle behind. However, I don't remember if the drag link ran backwards toward the knuckle with the steering box ahead.Maybe those were cabovers but memory is fuzzy.

On my ‘55, I needed a different length drag link and was able to get another suitable one that was too long. Found a place I could get a die and set it up in the lathe with spindle locked. Used one of my large Crescent wrenches to turn the die. Worked out well, gave my arm some good exercise. On some larger GM trucks they have 1” x 16 and 1” x 18 steering gear threads on the same truck, so measure carefully!

Threads in picture are covered by plastic pipe to keep dirt out.

Ed

Ed, you are a brave man working on the gravel like that. The ranch I bought had a gravel floor in the shop and I put up with it till I started working on some old British motorcycles with unique screws some of which I dropped in the gravel never to be seen again. In one deal, I traded the labor time on a job for the rig's owner to act as general and get me a concrete floor. The concrete mixer arrived with the crew right behind, some cash changed hands and I now have a reinforced concrete floor.

Part of my drive is concrete, however the problem is is is not properly drained, all downhill from large yard, so whenever it rains(rare this year) or snow melts, it collects under my project, so working in 4” of water has been helped by putting down gravel so one is not laying in water.

Ed

So is there any one particular spot that you guys would recommend to get the parts to rebuild my stock draglink. What I’m working with is a 51 1 ton Chevy. I ask this because of I have seen in some of the parts supply people that there are saying the 1/2ton to the 1.5 ton are all the same….. thanks, Joe

Well, a start would be to get new parts that would be as least as large a diameter as original. Then one can search for proper fitting taps and dies.

Ed

I bought the drag link repair kit and replacement balls from the Filling Station. Didn't have any issues with them. I believe the drag link is the same for '51 1/2 ton thru 1-1/2 ton.

Drag Link and Tie Rod Repair kit - PN FS-148
PR DRAG LINK BALLS - WELD-IN - PN SA-156

Thanks