Ford Power Assisted Steering Rack
I have replaced the Z steering rack with a Ford power assisted steering rack in my racing Z because of the large amount of caster built into the front suspension, the installation of very short steering arms (for quicker steering), and also because of the wide tires that will be used. In road racing, the higher speeds and lack of tight turns would allow me to get along with the stock rack, but I wanted to go slalom racing too, and being the slalom racing sometimes involves very tight turns and slaloms and slow speeds, I felt I would need either a power steering setup to get through the slalom course, or several cycles of body building steroids to enlarge my arms and chest. Needless to say, I chose the power assisted rack. I chose the Ford rack because it was one of the few that was designed for "front steer" applications, was made out of aluminum, and had relatively easy method of installation.
I took my rack off of a mid '80s Ford Thunderbird. The attached tie rod ends were too large for the existing steering arms, and being I wanted full adjustability for toe-in and bump steer, I opted to remove the tie rod ends, and instead use a spherical rod ends. The Ford rack has 9/16" threaded ends, which I found I could not get a rod end that would fit (the only available rod ends were and 5/8")**. Instead, I welded a stud onto the end of a 9/16" sleeve (a portion of the original Ford tie rod ends). With this "adapter" piece screwed onto the shortened end (by 2") of the Ford rack, I was then able to screw the spherical rod end in place. I then used a grade 8 bolt, run through the steering arm, through spacers for bump steer adjustment, and finally through the rod end. With the above mentioned 2" cut of the ends of the 9/16" threaded rods, I then had to add about of new threads onto the rack ends by running a die down this rod to create the addition of new threads. This then allowed me ample adjustment for toe in/toe out.
To attach the rack to the cross member, I welded two threaded bosses to the cross member to accept the bolts that pass through the rack and screw into the cross member.
To adapt the Ford rack to the Datsun steering rod, I cut the pinch clamp/U-joint combination off of a Ford steering rod, and carefully welded it to the Z steering rod. About 4" of Datsun steering rod needs to be removed to allow for the longer pinion stub assembly of the Ford rack. To remove any play in the Datsun steering rod assembly, I removed the large rubber coupling near the firewall, and replaced it with a aluminum plate.
The pump was then attached to the engine in a pretty much stock Ford manner as it was on the Thunderbird from which it came. I had some problems with fluid leakage on the pump (which seems to be rather common on these pumps) that was fixed with a small amount of silicone between the output hose connection and the plastic fluid reservoir, and by using a large (4" ) hose clamp to tighten the same plastic fluid reservoir around the metallic pump body where the factory O-ring was not sealing correctly. It's not a great design, but it is light. In fact, the entire Ford rack, pump, and hose assembly only weighs 9 pounds more than the Datsun rack.
** My ignorance of size availability (because I was buying the rod ends locally) of the spherical rod ends kept me from simply cutting a small amount off each end of the 9/16" rack ends, and directly using 9/16" female rod ends attached to the steering arms. The Z steering arms are about 46.5" apart, and the Ford rack (threaded end to threaded end) is about 46" long, with the last 4" on each end being 9/16" N.F. threads, thus leaving plenty to cut off to correct length.