October 2006 Old School Power AssistPosted in How To: Suspension Brakes on August 28, 2007
The steering system used by Jeep on the MBs and CJs up to 1972 consisted of a Ross worm/sector manual steering box and a drag link that connected to a frame-mounted bellcrank. This, in turn, directed individual tie rods to each steering knuckle. While it wasn't the greatest system, even when in like-new condition, it didn't take much wear in any of the components to make anyone following you wonder just how much you had to drink. Add larger tires, a heavier V-8 engine along with a Power-Loc differential up front, and you learned the meaning of "Armstrong steering."
Picture this for a minute: the bellcrank is mounted to the frame with separate tie rods to the left and right steering knuckles. Whenever the axle would move up and down with suspension movement, the wheels would either toe in or out, due to the fact that the distance between the bellcrank and the steering knuckles was changing with every bump. Now add some slop to the non-adjustable bushing that supported the bellcrank, wear to the ball and socket assembly on the drag link, wear in the steering box, and, well, it wasn't pretty.
The first practical solution I ever saw, around 1960 or so, was the Bushard bellcrank (yes, the same guy who made the trans adapters discussed in the May '06 issue). It was made farmer-heavy, flame-cut out of perhaps 3/4-inch thick steel with tapered bearings on each end so it was adjustable for wear. Next in the evolution was a swap to a steering box from a Hudson car. These were big, heavy cars, so the steering box was big and strong and had a much slower ratio than the Jeep box. It made steering so much easier, but still not right. The Bushard bellcrank got modified to where, with a combination of Studebaker car and Ford truck parts, you could have a one-piece tie rod that connected both front wheels together and a drag link to the bellcrank.
I am sure that someone had done the conversion before, but the first GM steering box conversion I ever saw was done by Jim Hicks in his Pomona, California, Jeep shop. This foreshadowed what was to come in the future by about 10 years. Soon, others were copying it. The early conversions used a long-style sector shaft raising the box up high in the frame where the steering shaft went through the grille or sometimes through the parking light hole. There were no kits to do this, so some of the conversions were pretty scary, to say the least. U-joints and couplers ranged from way-too-small aircraft components to super stout power-take-off shafts and U-joints.
At first, conversions were manual boxes, but it didn't take long to discover that power steering was the way to go, with the most popular being the GM power box with four mounting tabs. Mounting brackets were homemade and usually cut out of a 1/2-inch thick piece of steel and welded into the inside of the frame. A side benefit of this was that a weak portion of the frame was beefed up with the mount, and, naturally, the thing to do was add a plate to the opposite side. One tie rod connected the two steering knuckles together with a special tie rod end that had a hole that accepted the drag link from the steering box.
At first, not a whole lot of attention was paid to keeping the angle of the drag link parallel to the tie rod, so depending on just how steep the angle was, bumpsteer sometimes became an issue. Lift kits were just becoming popular and there were not a lot of dropped pitman arms available. Lots of wrecking yard searching took place looking for just the right arm with enough drop. By 1965 the new Wagoneers were out and were using the same Saginaw box. I like to think the engineers copied our earlier attempts. One nice thing that the engineers did was put an extension on the right-hand steering knuckle to accept the drag link. This made for a much stronger setup and gained additional leverage for better steering response. Naturally, we would scrounge the wrecking yards in search of Wagoneer steering knuckles. Now remember, these were still the old closed-knuckle design. Speaking of knuckles, a common problem was pulling the threads out of them where the spindles bolted on. The fix was to machine a small pad on the inside and screw in button head bolts from the backside. These now acted like studs and they couldn't loosen or pull out.
The Jeepster was next for the power steering in 1970, and by 1972, the front-mounted GM-style steering was standard in the CJs, with power steering an option. For many years, and still to this day, Advance Adapters sells power steering conversion kits for the early Jeeps.