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MG MGB Technical - steering wheel alignment

My steering wheel has been off centre for a while, but now it is starting to bug me. Instead of being straight accross, it is tilted to the right, a fair amount. How do I go about realigning the wheel?

Ken
70 B
Ken Harris

Ken. The coarse adjustment is to remove the wheel, turn it to the left and re-install it making sure the plastic collar for the turn signals is properly aligned. The fine adjustment is made at the steering rack's tie rods. The latter requires a front end alignment with the leveling of the steering wheel being one of the objectives.

Les
Les Bengtson

Les is right... you can do this adjustment yourself, if you are careful to maintain the alignment (or do an alignment by assuring that the toe-in is kept at zero).

What's a fair amount? I just straightened a friend's MGB wheel that was off about 10 degrees. I probably wouldn't hesitate to adjust one that was as far off as 20 degrees.

Do the proper coarse adjustment of the wheel, and alignment at the tires. The alignment procedure is the same as follows, except your first goal is acheive zero toe-in with the tie rods even (the same number of threads showing after the lock nuts). You can then alter the right or left tie rod ends by loosening the clamp on the small end of the gaiter (bellows) and the locking nut on the TRE. Rotate the tie rod the appropriate direction, and then rotate the opposite side the same number of turns, in the same direction. A test drive to determine if you were successful (you can leave the gaiter clamp loose for this test), and just readjust and drive again. Then, recheck your alignment. What you are doing is moving the rack relative to the straight ahead alignment of the tires, which in turns rotates the pinion which the steering column mates to, straightening the wheel. The alignment procedure is the same as follows, except your first goal is acheive zero toe-in with the tie rods even (the same number of threads showing after the lock nuts).

It takes very little adjustment at the rack to alter the steering angle. I found about 10 degrees can be ajusted with four flats of the locking screw, or 2/3 of a turn of the tie rod.

warmly,
dave
Dave Braun

oops. I repeated one of my sentances while editing on the fly... sorry about that.
Dave Braun

Ken This is one of the very few times that I will disagree with Les. All (or almost all) steering boxes are made with a high spot in the worm or rack. This is to allow for adjustment for wear in the straight ahead position. If you just change the wheel position on the splines your high spot may not be in the straight ahead position and result in a little slack. The way to do it properly is to find the high spot (sometimes there is a small line cut in the colume) and align the wheel to that. Then adjust the straight ahead with the tie rods. Shorten one and lengthen the other the same amount. If you have never had the steering wheel off the car the reason must be in the steering linkage. If you only had to move the wheel 1-1/2" you could take the chance but for any more do it the right way. There is little worse than a B with slack in the steering you cant adjust out. Denis
DENIS H

Denis,

You bring up a very interesting point. But after 36 years (and 163,000 miles) on my friend's B and 36 years and who knows how many on Ken's, how much of a high spot do you think is left? Secondly, how many teeth or how much range do you think is in a 10 degree adjustment? (I'm asking these questions seriously, because I find your comments wonderfully detailed and I'm curious as to your thoughts.)

I know that the steering wheel I was adjusting had been at least the fourth steering wheel fitted to my friends B. I'm embarassed to say that I thought I had the wheels straight ahead when I installed it by rolling the car in my warehouse, and still I managed to get it about 10 degrees to far clockwise. The first time I adjusted I ended up about 10 anticlockwise. Frustrating. But I split the difference and it seems fine. The car centers on the road very well, and just completed the drive to and from Gatlinburg, two quarts of oil, 2705 miles, 30 mpg, and no steering play!

Happily? or merely a coincidence?

warmly,
dave
Dave Braun

Earlier comments cover the adjustment, but there could be a history of adjustments of various accuracies already carried out by prevous owners, and you could end up with excessive difference in tie rod length that will induce bump steer.

To ensure that you are going to get as near as accurate alignment of the steering as possible, start off with both tie rods set at equal length with no toe in. This can be a bit of a pain as it involves removing the steering rack boots to ensure an accurate measurement.

With the wheels in the straight ahead position, remove and replace the steering wheel as close to the correct position as you can get.

Final adjustment can then be carried out by adujusting the tie rod ends as already described.

Cheers
ian F


Ian Fraser

Ken, are you talking about lateral alignment of the spokes of your wheel, or are you speaking about the alignment of the 'face' of your wheel relative to the dash?
Regards
Roger
Roger T

Dave and others, the high spot is there to allow for adjustment. Most of your steering is done in the straight ahead position so that's where most wear takes place and slack is a problem. If you adjust the slack out of mesh of the rack and pinion off the high spot you will get binding when the spot is passed in turning the wheel. As I said in my post the high spot usually has a mark scribed in the top of the column and the wheel is lined up with that. If the mark is not there turning the steering from lock to lock and counting the turns, then back to half is about the best. You may be lucky the easy way but I/m just passing on the correct and most accurate way. Also if the steering wheel is extra hard to get off it might end up being the easy way. Denis
DENIS H

In my experience, a little adjustment of the tie rods goes a long way in the centering problem. You may even be very close to keeping your toe in the same as it is now by first marking the tie rods with a scribe or marker. Then unlock the nuts and turn left and right equally, say one turn at a time, tighten the lock nuts, and take it out for a test. It's not too hard to figure out which way to turn, and if you go the wrong way, it's not at all hard to go back to where you started. Notes as to which way you turn each time on each tie rod might be a good idea.

I'm not saying that previous owners or whatever didn't mess something up. All the suggestions above are prudent. But if all looks normal under there, you probably won't even have to put it on an alignment rack.
Tom

Thanks for all your comments. The car drives perfect, and tracks straight when i let go of the wheel, so alignment is not the issue (i think). To answer Roger's question, it is the alignment of the steering wheel spokes. I have 3 spokes, 9 o'clock 3 o'clock and 6 o'clock. They are now at approx. 11, 5, 8. It has been this way since i bought the car 3 years ago, never really bothered me til now. I don't know what if anything the PO did, but the Tie-rods seem even (# of threads on each end).

I'll try pulling the wheel off and replacing it straighter. The "high spot" mentioned. Is the mark you speak of on the steering wheel column or the steering rack?

Ken
Ken Harris

Ken, I looked at two spare collapsible columns and cannot find marks on them. I believe Denis is saying the mark should be at the top of the column. On page J.4 section J.1 of the MGB shop manual there is a note on aligning the steering rack.

"NOTE.-To ensure that the steering gearbox is in the central position and that the steering geometry is correct, it is important that the tie-rods are adjusted to exactly equal lengths. This can be ascertained by measuring the amount of thread visible behind each lock-nut, which should be equal"

Clifton
Clifton Gordon

I have a problem with this 'high point'

It may be a feature of steering boxes of other design and manufacture, I can't see it as a feature of the box used in the MGB.

If it exists, it surely must be incorporated into the rack in by way of extra overall thickness at the pinion contact area in the straight ahead position, or by some ovality in the pinion.

The design and adjustment mechanisim where a spring loaded plunger engages the back of the rack to ensure that the rack and pinion are kept in contact, backed up by the shim adjustment that ensures that the travel against the spring plunger is limited makes any prebuilt high point un-necessary. In any case, location of this 'high point' in the process of aligning the steering wheel is un-necessary, as the rack will be in the correct position when the front wheels are in the straight ahead position, and the tie rods are of equal length.

If the 'high point' is in the pinion, it would mean that the pinion is oval in some way, which is a bit odd. Even if so, there is no warning in the manual to reassemble the pinion to the rack in any particular alignment, so that in any service the meshing of the pinion to the rack in any particular place is liable to be lost anyway which would mean that any marking on any other component of the pinion shaft/steering column assembly would have no meaning.

Cliftons extract from the manual reinforces my point - Ensure that the tie rods are of equal length, then set about adjusting the position of the steering wheel by removing and replaceing untill it is as close as possible to the desired position, final adjustment by tweaking tie rod lengths. (although I personally would not do this last adjustment).

Cheers
Ian F




Ian Fraser

I think the high spot would have to be built into the rack, if the pinion is oval there would be three high spots with the approximately 3:1 gearbox ratio used in the MGB rack. I do know that most recirculating ball and other non R & P gearboxes have a high spot at the center, I've never seen it mentioned in the manuals for any vehicle with R & P steering.

Clifton



Clifton Gordon

If you had no high spot and had wear in the straight ahead position were 90% of driving is done, the box would bind on turns if the slack was adjusted out. If you have a problem with whether it exists or not read more about steering box design from a quality automotive technical publication. Don't get me wrong there are good handy books around for the DIY owner but they don't tell the whole story. Denis
DENIS H

Hi Denis.

There may be a high spot on other steering boxes, and it may well be a feature of their design, I am not disputing this. But the evidence that I have at hand points to this not being so on an MGB box, and in any case is not relevant to Kens original problem of aligning the steering wheel.


Things that point to this are:

- There is no mention of this in the workshop manual.

- The procedure described for adjustment of free play does not mention that adjustment should take place in the straight ahead position.

- The shimming clearance prescribed is from 0.0005" to 0.003", and without special mention in the manual it is assumed that this clearance is correct for any position of the rack relative to the pinion. If there was a high point it will have to be less that half a thousandth of an inch.

- The problem that you describe of binding at each end of the rack travel is an fact a common problem on MGB boxes after some wear has taken place and adjustment in the straight ahead position has been carried out. It is usually solved by carring out the adjustment at the end of the travel. (or replacement of worn components, or the whole box)

In the MGB box, it is apparent that some provision for wear is made (in a fashion) on racks during manufacture by flame hardening the rack in the central position. This can be seen even on an old rack as discolouration of the rack surface.

A definitive answer could be obtained by measuring up a new rack, but alas I do not have one of these.

Cheers
Ian F












Ian Fraser

BTW - My reference is an original print BMC workshop manual rather than a handy DIY reprint.

Ian F

Ian Fraser

This thread was discussed between 14/07/2006 and 17/07/2006

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