Do not over-think this. You are right about the adjustments at the tie rod ends. There are way more threads there than necessary to solve this.
I have a deep appreciation for your experience, but you did not mention anything about airbags. Please forgive me if I am discussing a subject you are familiar with, but it might be of value to others researching this topic. Cars with airbags have a clock spring under the steering wheel. That is a wound-up ribbon cable in a plastic housing. The cable eliminates the need to rely on a sliding contact at the instant you need that airbag to deploy. The important concern is that ribbon cable is just long enough to allow turning the steering system fully-right to fully-left, and very little more. Standard procedure is to center the steering wheel and lock it there with the ignition switch or a rope, rubber strap, etc., so it cannot rotate. Now remove and replace the rack assembly with the new one also centered. You can easily twist the input shaft a quarter turn without causing a problem. Once installed while it was centered, the rack will limit how many revolutions the steering wheel, and clock spring, can be rotated, so you will not be able to extend the ribbon cable beyond its limits. If that were to happen due to something being not centered during the installation, the clock spring could be turned one revolution too far to the right, or one revolution too far to the left. In one case the cable will become tight and get torn off on one end. That would show up instantly as the "airbag" warning light stays on, and the horn and cruise control would be dead. In the other case the cable will unwind too far, then fold over on itself. That would not show up for a while until that flexing finally caused the cable to crack apart. That could take days or months to show up.
The second issue has to do with the orientation of the flat spot on the splined input shaft. GM had a huge problem with their steering gears starting in the mid 1980's, called "morning sickness" because that is the only time most problems first showed up. GM's fix under warranty was to replace the spool valve which includes that splined input shaft. There are four Teflon rings that would leak and let pressurized power steering fluid bypass the power piston instead of push on it. The symptom always was loss of power assist in only one direction, for the first few seconds when the cold engine was started. Power assist would return very soon.
Over the course of a few weeks, that loss of power assist became longer and longer. Hot power steering fluid was needed to make those sealing rings expand, then the power assist would return. If you put up with this for up to a few months, the same problem would occur when turning the other direction. Eventually it would get bad enough that power assist would never return. The actual cause of this fluid leakage was not addressed by the warranty repair. Grooves were being ground into the soft aluminum housing where the Teflon rings were supposed to seal against. They wanted the spool valve/rings to be replaced, and did not care about the grooves. It took one of the nation's premier aftermarket re-builders to come up with the permanent fix. They bored out the cylinder, then pressed in a stainless steel liner for the rings to seat against. GM's only concern was to get the cars out of the 50,000 mile warranty period. After that, when the problem occurred again, as they all did, it was up to the car owner to pay for the proper repair which was to replace the entire steering gear.
Where this story has relevance is you asked about reorienting that input shaft. Replacing the spool valve was done from under the dash, without removing the rack assembly from the car. This was described to me by a former coworker who had worked at a GM dealership during this time period. He said you only needed to rotate the shaft by hand and let the pinion gear push the new spool valve back out, then turn it one or two teeth one way or the other, as necessary, to again have a straight steering wheel. You should be able to do the same thing after removing the snap ring. You will have the advantage of not slobbering power steering fluid inside the car.
Some of the people at the rebuilder shops can be quite conscientious, but not always the best-trained. The person who assembled the rack you got might have thought close enough was good enough when he stuffed the spool valve in. Remember, you can make up that difference at the tie rod ends during the alignment. There is no high point in a rack and pinion assembly like there is with the recirculating ball steering gear box. Any point along the rack can be the center point without causing it to want to fall to one side or the other. What you could lose is the ability to turn fully to both sides equally. You might get two steering wheel revolutions to full-right and two and a quarter to full-left. For that matter, did you check the old one before you removed it? It is just as likely your new one is right and the spool valve in the old one was wrong. The clue would be to look at the shiny and rusty threads on the old inner tie rod ends and see if both had the same number of threads engaged with their outer tie rod ends. It is common to find roughly 27 to 29 threads engaged. If one was 35, for example, and the other one was 20, that would point to the old steering gear as the one with the problem.
As a side note, as the only steering, suspension, and alignment specialist at a very nice family-owned dealership for ten years, I replaced a lot of rack assemblies on new and trade-in cars. I never once counted the exact number of turns of the input shaft like you are doing. All I ever did was check that both accordion boots over the inner tie rod ends were extended an equal amount, then I turned the input shaft to match the steering coupler. Had I received a rack assembly with the issue you are worried about, I would never have known it. I am happy you are concerned enough to ask, but you do not really have a problem.
If you are unlucky enough to have a damaged clock spring, and if you need advice on replacing it, you can check out this article:
https://www.2carpros.com/articles/steering-wheel-clock-spring-removal
Or you can go to the top right of this page and click on "Repair Guides" to see the other articles available.
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Monday, September 17th, 2018 AT 9:18 PM
