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Power Steering Conversion (FJ40/Saginaw)

Power Steering Box

The first, and most critical, component of the power steering conversion was the steering box. We used a Saginaw 4-turn 4-bolt box from a GM late-60's vintage car, acquired from a local wrecker. The box mounts behind the front bumper, on the inside of the driver's side frame rail.

The box is recessed into the frame cross member. This provides good steering geometry, and, because the box is tipped up, reduces the angle of the u-joint in the steering column. Also, it allows the oil lines to hide under the front cowl. All in all, a very clean setup. But, the cross member must have a large hole cut into it, which requires stiffening plates to be welded above and below. Also, the box is positioned so it doesn't interfere with the bumper and tow hook bolts.

The box is bolted to a 3/8" plate which is welded to the frame rail. The four mounting bolts tighten into threaded holes in the cast housing of the steering box. The lower two (short) bolts are below the frame, but the upper two (long) bolts must pass through the frame rail. Steel tubes are welded into the frame rail to prevent the tension in the bolts from buckling the box frame. The bolts pass through the steel tubes. A Pitman arm that's 6.5" long (hole center to hole center) with 2" of drop is about right.

Steering Column

The existing steering column is cut off just above the rag joint. The last 1/2" of the 19 mm steering shaft is ground down slightly, to fit the 3/4" hole in a keyed yoke (Spicer part no. 10-4-13), which is held in place with a set screw and welded on. The steering shaft is a custom made steel shaft with keyways cut into either end, to mount into the slip yoke at the top and a keyed yoke at the bottom.

A splined yoke (Spicer part no. 10-4-501sx) is purchased to fit the splines on the steering box (with some minor alterations). A pair of u-joints to fit the yokes completes the steering column. The splash guard beneath the fan is notched, to allow the shaft to pass through.

Finally, a pillow block bearing is mounted to the frame on a steel bracket (see prior image) using the old steering box holes. The pillow block rigidly supports the shaft, thereby supporting the steering wheel, which is otherwise loose. The bracket is made from:

An alternative arrangement is to mount a pillow block bearing to the firewall, where the steering column protrudes. Be sure to assemble the entire steering column, and mount the pillow block bearing, before welding any yokes or keys into place!

Power Steering Pump

The power steering pump is the second major component of the system. It is mounted to the passenger side of the engine block, and driven by a belt from the crank pulley. This requires a double pulley, which is not always stock. We scavenged one from an older model cruiser.

The mounting bracket is bolted to the three threaded holes which ordinarily hold the hook that's used for pulling out the engine. Notice the notch cut in the bracket to allow access to the #1 spark plug!

In order to tension the belt, the pump mount is in two pieces, mounted together with bolts through slots and a lead screw to raise the pump. The lead screw is tightened until the belt has enough tension, then the slot bolts are tightened.

Oil Lines

The last job is to connect the pump to the box with high pressure oil lines. We used a rigid steel line for the high pressure feed line, and flexible hose for the low pressure return line. A short length of high pressure flexible line (bought as a unit with fittings attached) connects the steel feed line to the pump, to allow for engine vibration without stressing the steel line.

The lines run down the passenger side of the engine bay, in front of the battery tray, along the frame rail, along the cross member (under the cowl), and finally to the box. The lines are held in place by custom clips, bolted to the frame.

Summary of Parts

For more information, or comments, or constructive criticism, please contact the author.