Drag link, pitman and steering arm
by Jim "Caroline's Truck" Wilson
Here's a fairly easy upgrade to help make your steering safer and easier to keep adjusted. Don't settle for a wobble or a crazy angle on that steering wheel! Straighten up and drive right!
Remember to click on the images for an enlarged view.
This technical tip is for a completely adjustable drag link for pre-1953 Advance Design trucks. This adjustable drag link may also work for other years of trucks, such as Task Force and later, but that is something the owner will have to determine.
When I started on my rebuild, I really did not realize it would turn out to be an off-frame restoration. I got to looking at the front end on her, and the king pins were shot. So a total rebuild was started.
As I looked at the old-style ball joints and the current replacements, as well as a fixed drag link, I got to thinking about having it all completely adjustable. I thought this was the time to make this modification. I looked at the brakes and decided to upgrade and get 6-lug disc, taper bearings as well as the dual power master cylinder. You may not know how badly the front end parts were worn until you get it all apart. All the ball studs could be egg shaped (mine were) and have gouges in the necks from over tightening of the end caps over the years.
A close look at three major components. The tie rod has an adjusting fixed nut, the Pitman arm (sometimes called a connecting rod) has it’s taper hole. The new modification shows the two tapered tie-rod ends with the adjusting pinch coupler Drag Link.
Centering the steering wheel on that "high spot" so the truck will go down the road straight and hold the road with no shimmy or wobble is much safer. The adjustable drag link will give you the ability to get that wheel perfectly centered. The adjustable tie rod style drag link, with tie rod style ends, will add just that much more controllability to the vehicle and I think you will find it drives significantly better.
The stock pre-1953 Advance Design trucks have a ball and socket arrangement on the pitman and steering arms, as well as sockets on the drag link and tie rod ends. All these can be changed out to modern upgrades of tie rod ends with tight tapered joints.
This picture here shows the right concept but it's the wrong picture for an AD.
I did a search on The Stovebolt Page under "tie rod," "drag link," "pitman" and "steering arm" and got a some responses and guidance from a few fellows who had made their own drag links. Armed with little knowledge, I researched vendors and other sources and came up with several possible solutions. It was now time to document this process. (Check the Tech Tip done by Wayne Osborne and Paul Franchina / Chevy Trucks. org for the Tie Rod Replacement.)
Chevy and Ford have different taper angles on their vehicles for various models over the years. (I believe Chevy is a 6 degree angle.) I also understand that newer trucks have a larger diameter than older vehicles. Sorry, I do not know that year date for that change.
I started my research and found some things from Speedway Motors and Classic Performance Products. As it turned out, I had these catalogs and found the adjustable models of tie rod sleeves from 8'' to 24'', in steel and aluminum, 5/8'' and 3/4''. All the parts are available from your FLAPS (Friendly Local Auto Parts Store, like Napa).
The pitman arm is made to come off with a puller. There should be no play when it is seated on the splines, and force from a hammer just causes it to jam even more. The puller provides even tension. Try any penetrating oils to loosen it first. It’s best to leave the nut loosely on while using the puller until you get it loosened up so it doesn't pop off and cause you harm. The pitman arm puller can be loaned from the flaps stores or any good tool rental place.
The tie rod end has the 3/4’’ nut just up from the thread end. The other passenger side steering arm is not shown here. The upgraded drag link, disc brake and hub plates.
The hidden end of the drag link should not be too hard to get off, but a "pickle fork" makes it easier - the removal of the joint between the steering box, pitman and drag link (with the correct equipment) did not take that long to complete. Cotter pins hold a big slotted plug in place, under which is a spring and the ball socket for this removal. Remove cotter pin and then back out the screw and that should allow you to disconnect the connecting rod from the associated ball end / arm. The tie rod is left alone (except for the welded nut modification), because the newer (vendor sourced) ends can thread on and have a pinch bolt to hold the end tight. After I removed the old ends, I welded two 3/4’’ nuts about two inches in from the ends of the threaded portion of the tie rod, so adjustment / turning is easier, foregoing the vise grip marks commonly found here. I had to drill out the threads of the nut and hack sawed a slit. I widen the slit with a large screwdriver and slipped it over the end of the rod. Use a vise grip to compress the nut back to shape around the rod and give it a couple of good tack welds to finish it off. Then blast and paint. You’re done with the long tie rod.
The new drag link modification (mod.) will have the adjustable rod ends. The Napa tie rod ends you buy are designed to fit into the new taper holes in the arm ends and have an adjustable pinch coupler. The steering arms come off the hubs with the removal of two bolts on each side. The tie rod ends of the steering arms can be sourced from any vendor and should fit in the holes at the steering ends. The steering arm hole ends at the tie-rod do not get re-amed. Only the curved end on the driver’s side steering and pitman arm ends get a taper ream. The mod. new taper tie rod ends fit tightly into the tapered hole. It will be necessary to remove, grind, and drill out all the ball ends of the steering arms as well as the pitman arm, (see the Tech Tip for removing / replacing the Tie Rod).
This shot is the completed drag link upgrade modification on Shipwright’s beautiful red sled truck (1949 Chevy 5-Window Deluxe Cab). If the big nut was welded on the tie rod shaft inboard about 2’’ from the threaded end, it would eliminate the dreaded vise grip marks shown during adjustments.
After you remove all of the old ball ends completely, the holes that do get the new taper will probably have to get welded for the hole resizing. Grind and / or drill into the rivet to hit it out -- it should come out. You can drill up to the size of the replacement bolts. I think it's 5/16 or 3/8 inch and punch it off with a BFH -- it should pop out. If not, spray with a penetrating fluid again, wait and drink more beer. Then try again. Some machine shops or 4-wheel drive shop facilities can also do this sort of thing for you if you do not have the correct taper reamer, time, tools or energy.
I used three items from Napa -- #269-1118, #269-2078 and #269-2225 (the sleeve and two tie rod ends). It all looks super and is very tight. Any of these suppliers will have what you need. It's a great safety upgrade if you have steering problems and have not looked at those components.
Next I’ll add a steering stabilizer and sway bar, the rear bar is going on now.
I assembled the front end. What you will notice are the two steering arms will line up ''geometrically'' with the differential’s u-joint at the rear end and, no they are not bent -- they just look that way. Shipwright (1949 Chevy 5-window Deluxe Cab) has done this modificcation and bowtiesr4me started.
Use anti-seize grease when re-assembly is done on all threads, tapers and splines. Don’t forget to grease all of the zerks. Now enjoy your ride through the countryside.
Jim and Caroline Wilson
1951 Chevy Delux 3104
Bolter # 4758 Inliner #2100
Grass Valley, California
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v. February 2007
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