Box: The steering gear box is a four-bolt, four-turn Saginaw Model 800 box. The box is mounted in the traditional fashion by welding scab plates to the inside of the frame rails. For additional strength, I also welded a scab plate on the outside of the frame on the driver's side. Bolt holes through the frame are sleeved. The box was modified to allow for hydro-assist steering by machining hydraulic ports into the fluid channel ways in the Saginaw box. The fittings for the hoses running between the gear box and the hydraulic ram are indicated by the arrows in the image to the left.
Column: The steering column is a GM tilt column from a 1974 Camero/Firebird. These columns are relatively easy to adapt to a Land Cruiser. The fitting on the column support arm can be modified without much effort so that it bolts to the bottom of the dash, just like the OEM column. The second modification that is required is to fabricate and weld a plate onto the steering column housing that allows it to be bolted to the firewall of the Cruiser (right image). The older style tub with the elongated firewall hole makes this an easy project. The GM column also has all of the wiring and switches that could be incorporated if desired. Since the truggy has no windshield wipers or turn signals, I removed all of the wiring except for the ignition switch.
Shaft: The steering shaft is a 3/4" Borgeson DD shaft with the Borgeson needle-bearing u-joints. The image to the left shows the end of the Camero steering column sticking through the firewall and its connection to the Borgeson shaft. I welded a solid piece of .750" DD shaft onto the end of the GM column. This piece then mates into one end of the upper u-joint. As shown in the images, the steering shaft nicely clears the exhaust manifolds and power steering pump (not shown). The lower u-joint connects the DD shaft to the splined input shaft of the Saginaw 800-series gear box. Also visible on the firewall are the master cylinders for the clutch (right) and brakes. The brake master is a non-boosted master from a Ford F350.
The tie rod and drag link are made from 1.375" DOM tube with a 0.375" wall thickness. All tie rod ends are one-ton units with a 1.0" threaded shank. I cut left- and right-hand threads in the DOM tube (no weld inserts used) and also made the stainless steel jam nuts from hex rod.
Steering Arms: The Dana 60 front axle uses a king-pin type of knuckle that allows for a custom hi-steer type of arm to be bolted on top of the knuckle assembly. With the big tires, I wanted to design a steering system that would spread the forces involved with steering more evenly between both knuckles, the drag link and the tie rod. To achieve this goal I made a pair of double steering arms. These arms place the tie rod behind the axle, out of the way of rocks and other obstacles. The front half of the passenger's side arm is connected to the drag link from the power steering box and the front half of the driver's side arm is connected to the hydraulic ram.
With this arrangement during a turn to the left, the drag link pushes on the passenger's arm while the hydraulic ram pulls on the driver's side arm. The arms themselves are made from 1" thick T-1 steel. The pieces were rough cut with a CNC flame torch and then finished on my milling machine. The arms are 14" long and 3.25" wide. The king-pin to TRE-center distance is 6.5" -- the same as the length of the Pitman arm I use on the Saginaw gear box. Since this is strictly an off-road rig and the differentials will be locked most of the time, no effort was made to produce correct Ackerman geometry by making the rear of the arms narrower than the front. A 2.125" hole was milled in the center of each arm and the king-pin cap was welded into the arm. The arms are bolted to the knuckles with 4 studs. I tapered the top end of each hole in the arm to allow the use of tapered (lug-nut style) nuts on each of the studs. The holes in the end of each arm were drilled and then taperd to fit the one-ton tie rod ends used on the tie rod, drag link and ram end.
Hydraulic Ram: The single-ended, hydraulic ram is shown to the left. It is a 2" ram with an 8" stroke. It is mounted on each end with 3/4" heim joints. The stationary end mounts to a mounting plate that bolts onto the top of the Dana 60 axle housing. The tie rod is visible in the background.
Pump, Reservoir and Cooling: The hydro-assisted power steering setup obviously requires an increased volume of fluid in the power steering system. Furthermore, compression in the hydraulic ram adds considerable heat to the fluid. In order to address these issues, I added an external fluid reservoir and a 2" x 24" frame-rail cooler. Pictures of these items will be forthcoming. The pump itself is the OEM Saginaw pump on the Vortec. The flow rate through the pump was increased by the modification developed by Matt Hodges of West Texas Off Road. I did not attempt to increase the pressure output of the pump.