Reply to "Ferrari 308 steering rack - but which one?"

I received my new 308 rack from BUYAUTOPARTS.com. This weekend I removed my original (rebuilt in 2002 with bushing and new lower pinion thrust bearing) to do a comparison.

Like others I've seen with the 80-70007 AN part number, mine has a black middle tube. There are no part numbers or markings of any kind on the rack. As noted above "It does seem a bit tight, there is certainly no slop. I'd expect it to be a little smoother." It seemed a little stiff to me, but when I compared it to my original rack, it was not much different. I measured the torque applied to the input shaft needed to turn it with no load. Using a digital luggage scale and a pair of vice grips I measured <.65 ft-lbs. My original rack measured about 0.5 ft-lbs. It has about 120K miles on it and 15K since its rebuild. At the steering wheel I doubt if these differences would be noticed. What really matters I how much friction there is under load. I have no way to measure this. My guess is there is about 5% loss.

I noticed a variation (somewhat notchy) effort as I turned the input by hand. This was noticeable on both racks. The "vibration" it caused was really noticeable when moving the rack back and forth by push/pulling on the tie rods. On the new rack, it took about 15-20 lbs of force on the tie rod to move it. My old rack took 10-15 lbs. These forces seem consistent with the 17.45:1 ratio (seen on one spec sheet) the input torque I measured.

I played with the adjustment screw to see if I could lower the friction. Backing it out didn't seem to reduce the forces but if you tightened it down you could lock things up. My guess is the it's purpose is to compensate for wear and to keep the dead zone to a minimum as things wear. I removed the two caps on the rack/pinion housing. The photo below shows the screw adjustment assembly. Notice that the lubricant is grease, not oil. The lower thrust bearing is under the other cap.

Finally, I was impressed with the quality of the rack's materials and workmanship. I'm sure it will last and work as well or better than the original.