|The MGA With An Attitude
STEERING COLUMN Rotational Alignment - SR-108A
On 1/23/2017, Alan Wiedie wrote:
"I rebuilt my 1500 steering rack and was very careful (I thought) to centralize the rack in the housing before and during inserting the pinion shaft. Now, with the adjustable upper steering column back in the car and the u-joint installed, and with what I calculate is the midpoint of full lock left to right, the centerline of the locking collar is about 1 o'clock, 7 o'clock, or maybe a little more, instead of winding up 12 o'clock, 6 o'clock. .... I guess the question is, should that locking collar be straight up and down at wheels straight ahead at center lock, or doesn't it matter"?
After multiple questions, great fanfare and lots of research, this turned out to be much ado about nothing. The short answer is, apparently the factory thought it should be random orientation. That figures, as it has nothing to do with making the car move, so no sense wasting time fooling with the trivial detail. But you can read the rest if you have the time.
As long as it doesn't bother you too much, I don't suppose there is anything magic about the clamp bolt being vertical. I just checked mine, and perhaps by sheer coincidence it is vertical on the left side of the column with bolt head up and nut down. My U-joint upper bolt is vertical on the left side of the column, and the lower U-joint bolt is horizontal on the bottom side.
I have had the steering column disassembled a few times, and the steering rack completely disassembled at least twice, changed the U-joint a few times, as well as rebuilding a few other racks. I can't recall as I ever paid attention to the orientation of the input pinion shaft (probably did), but it is pretty obvious how to get it all aligned if you were so inclined.
If you like, you can start with the upper steering column rotate it to any position you prefer, and maybe install the steering wheel to make it obvious and not lose track of it. Then install the U-joint on the upper column, and make note of orientation of the U-joint, which will dictate desired orientation of the lower column.
The U-joint is essentially keyed to the shafts with the pinch bolts. You cannot turn the U-joint one spline, or the bolt won't go through.
Once you know the desired position of the pinion shaft, you look to see if the rack travel is centered. Turn it all the way lock to lock, counting the turns, which should be 2-2/3 turns for the stock MGA rack. The turn it half way back to center it which should be 1-1/3 turns. It may help if the steering wheel is in place for position reference, so you can see the position at ends of travel, which should be mirror images. At center of travel the wheel should be level.
If the steering wheel does not sit level at center of travel, the simple solution is to pull it off, reposition it level,and stick it back on (to the nearest spline before adjusting tie rod ends). That may defeat your intention of making the clamp bolt come out vertical.
If you are determined to reposition orientation of the clamp bolt, then you have to remove the pinion shaft from the rack to turn it to the desired orientation. I'm pretty sure this can be done without disassembling much else. Remove lower U-joint bolt. Remove the bottom end bearing cap (two bolts, don't lose the shims). Push the pinion shaft downward, and pull it out beneath the body front valance panel.
Do not lose the thick spacer thrust washer that resides on the pinion shaft above the pinion gear. This has a particular orientation and needs to be installed correct way around. If I recall correctly, maybe the spacer (thrust washer) cannot be removed without removing the gear rack first (which would be a good thing in this case). For reassembly, be sure the rack is centered when you install the pinion shaft in desired orientation.
When reassembled center of rack travel should put the steering wheel right side up with the shaft clamp in your desired orientation. Then you "clamp: or hold the steering wheel horizontal while you do the front end alignment so the tie rod ends will be (approximately) same distance screwed onto the tie rods. The steering wheel must then be held centered and level during fine tuning of the front end alignment and toe-in adjustment so when it is finished it will track straight down the road with the steering wheel level.
There will be some minor "misalignment" (so to speak) such the the tie rod ends are not absolutely perfectly the same distance on the tie rods, and end of travel of the rack in each direction is not perfectly symmetrical. This is limited by resolution of one tooth pitch of the pinion gear, and the nearest single spline on the steering wheel shaft end. I don't recall how many teeth on the pinion gear, but is it is an odd number you can reposition it by 1/2 tooth by rotating the pinion shaft 1/2 turn. That would maybe put your (vertical) upper clamp bolt on opposite side of the column, while the steering wheel can be repositioned to be right side up and level.
I suppose the proper approach is really to start at the bottom end while assembling the steering rack. Assemble the pinion shaft to be "level" (notch for the bolt to be at bottom) when the rack is at center of travel. I think that is what I have always done, probably not by coincidence, but from thinking about how the U-joint and steering wheel should be oriented while assembling the rack assembly. In other words, think ahead, or look where you are going before you leap.
I was just reading the Workshop Manual. It definitely tells which way around the thrust washer has to go, slotted side away from the pinion gear (if it may actually be correct), and that it has to be installed before the gear rack. I seem to recall putting the upper thrust washer wrong way around once, and the pinion shaft wouldn't go all the way in. That may be due to an error in the Workshop Manual (but I can't swear to it just now). I will have to see if I wrote something about that in my tech pages.
For sure, the Workshop Manual does not say one word about orientation of the pinion shaft. Illustration in the book shows RHD installation with lower U-joint bolt horizontal on top, and upper U-joint bolt vertical on left side. (But the technical illustrators are often wrong, taking great liberties to make the illustrations easier to draw).
It calls for installing the steering rack and column loosely (no mention of rotational orientation), then tighten the U-joint bolts, then tighten the lower steering column mounting bracket. This is to get correct alignment of the shafts. While the U-joint is holding the shafts in proper alignment, then shim the rack housing at the frame pedestals (if necessary) before tightening the rack mounting bolts. (Still no reference to orientation of the upper clamp or steering wheel).
What it says about alignment is to adjust both tie rod ends to the same length first to assure the rack will be centered. Then do front end alignment (toe-in adjustment) by turning both ends the same amount (to keep it centered).
After front end alignment is finished it mentions installing an adjustable steering column, like it is an accessory replacement for the standard steering column. The very last step is to install the steering wheel (to be level when steering rack is centered). There is no reference to realigning the front end after installing the steering wheel, so in theory they think getting it as close as the nearest 1/2 spline pitch is close enough to level.
If you don't like position of the steering wheel you can take it off and reposition it one spline over, but that's it. But we all know better. Any front end alignment shop doing the toe-in adjustment will lock the steering wheel level before adjusting tie rod ends, so when finished the wheel will be perfectly level during road travel. If this is what you want, then it may be necessary to realign the tie rod ends after installing the steering wheel.
But in any case, apparently the factory intended for the steering U-joint and the adjustable column clamp to be in random orientation, as they have not wasted one word to the contrary. The chrome clamp for the column length adjustment (if it has one) cannot be rotated on the shaft, because the clamp bolt fits in a relief notch on the shaft (same as the U-joint clamp bolt).
If the pinion gear has 9-teeth, then rotating it one tooth before installation will re-orient it by 40 degrees. But being an odd number of teeth if you rotate it as near as possible to 1/2 turn, it will change by 160d or 200d, (not 180). The bolt slot (and clamp orientation) will then be on opposite side and closer to vertical by 20 degrees. You don't have to pull the pinion shaft all the way out. Disconnect it from the U-joint, then pull it down just enough to disengage the pinion gear from the rack teeth, turn it one tooth and reinstall it. Or turn it 1/2 turn (160 or 200) and reinstall it.
You should be able to get the clamp bolt straight up like mine. I suspect the factory used the bolt groove to hold orientation of the shaft while machining the pinion gear teeth. Or if they cut the gear first, then hold the gear in fixed orientation while cutting the bolt groove, In either case, I think all pinion shafts should have same relationship between bolt groove and pinion gear.
Put a tape around the pinion shaft. Turn the steering all the way to one lock, and mark the tape on top. Then turn the steering all the way to other lock, and mark the tape on top. This should be 2,6 turns total. or 1.3 turns from center of travel each directions. Then turn steering back to center (1.3 turns). You will end up with the two marks about 0.15 turns (54 degrees) either side of bottom center. Turn it until the two marks are symmetrical, same distance either side of center, and you can put another center mark on top if you like. When you have the rack centered in this fashion, then install the steering wheel to be upright and level. Then block or tie the steering wheel in that position while you adjust the tie rod ends to have the front wheels pointed directly forward and parallel.