Friday 7 February 2020

Relating to Morgan Steering Column Linkages

Relating to Morgan Steering Column Linkages

This topic was first raised by Heinz, a contributor to the 'Talk Morgan' Forum. Then a Roadster 100 Register member stated: I found this article very interesting. I have had Allon White’s look at my steering without any joy, so I tend to put up with the vibration and wobble, putting it down to a Morgan quirk, and British road surface quality.

I wondered whether the company commented on the safety of this situation?  If there is so much strain that the components bend, surely they may break under a fairly high speed turn?

Has anyone in England had a steering specialist look at theirs?  I found a company called ICS in Birmingham, (http://www.ics-steeringspecialist.co.uk/)  that specialises in classic cars and wondered whether anyone had used them?  

Further comments would be interesting. So here goes.

The Roadster 100 Situation.

I have been studying the steering column on our R100 today following a study of Dave Wellings Book ' Buying and Maintaining a Modern Traditional Morgan' and 'Making a Morgan' Book by Andreas & Dagmar Hensing.

Dave says that there are Two Universal Joints on the Column when in fact on the Roadster 100 and presumably other later Morgans there are four Universal Joints.

I was going to dismantle the covers around the Adjustable Steering Column but clear photos in the Hensing book prove two things: 


The Pre Assembled Adjustable Steering Column Section. 

1. There is a 4th UJ in the line located behind the Adjustable Height Steering Wheel. 

This is now the First UJ in line whose Swivel Pin must be horizontal when the Front Wheels are in the straight ahead alignment, when the Steering Wheel is attached and when the Lowering Action is applied. 

(Parts seen in box above with its Swivel Pin in the Horizontal position).

2. This Spring Loaded Unit is pre assembled by the Sub Contractor, but the other 3 Splined Joints ( Two Shafts & Steering Rack ) are assembled together in the Morgan factory.


The Two Tensioning Springs on the upturned unit.

These splined joints are therefore subject to possible location error when assembled in the factory. 

If the swivel pin of this UJ was less than horizontal ( e.g. in the X orientation ) when trying to lower the wheel height then the 'Bending Action' or 'Strain on the Joint' that Heinz referred to could occur. 

After all, One would not adjust the Headlight Beam or the Rear View Mirrors with the car on a bend in the road therefore why would anyone try to adjust the Steering Wheel Hight with the road wheels facing other than Straight Ahead?

Miss alignment of the Universal Joints could occur if the factory does not take care with shaft assembly and ensure that the Road Wheels are Straight Ahead.

This needs to be so, both when the correctly assembled Shaft is attached to the Rack Spline and the when the Steering Wheel is finally attached to its Top Spline.

The Correct Set Up


When the Front Wheels are Set Straight Ahead.


The Steering Wheel should also be seen in this 'Correct Position'.


The 'First' Universal Joint Swivel Pin to be found within the Cabin, located behind the Steering Wheel, should now be in the Horizontal or '+' orientation.  


The 'Second' Universal Joint Swivel Pin to be found just in front of the Firewall Bulkhead should also be in the Horizontal or '+' orientation. 


The 'Third' Universal Joint Swivel Pin, to be found just inside the small box covering the hole in the engine bay side wall, should also be in the Horizontal or '+' orientation.  


The 'Fourth' Universal Joint Swivel Pin, to be found where the shaft meets the Steering Rack, should also be in the Horizontal or '+' orientation. 
Seen here from the side view.

  
Seen here from above.

My conclusion is that when the wheels are facing straight forward, the swivel pin on each of the 4 Universal Joints are all assembled horizontal or '+' orientation 



rather than assembled at random angles which could cause conflict during turning.



I then put our wheels on full lock, or as near as the wheels on the gravel would allow, and found that all 4 UJ Swivel Pins are all in the horizontal or '+' orientation. 

The Adjustable Height of the Steering Column

The Steering Height Adjustment is such that when the locking lever is freed the wheel rapidly moves upwards as far as it will go.

This is caused by contraction of the two heavy springs located inside its pre assembled housing. 


The Steering Column Height Return Springs

That upper location is the position that our steering wheel has always been set.


However, if the Wheel Height is lowered and raised rapidly you will notice absolutely no movement of the column shaft appearing through the firewall under the bonnet .

Thus I, like Heinz,  discovered that the first of the 4 Universal Joints must be located inside the Cabin.  

.............................................

After reading my comments above, Heinz has added these additional comment regarding my assumptions.

Regarding the text in the blog in front of my post:


I did not think so far that when the wheels are in a straight position, it is absolutely necessary that the cardan shafts are horizontal - in relation to the wheel position. In my opinion it is important that the forks of each cardan shaft and in connection to the next cardan shaft must be "in line" as described in my post. And exactly this as also in the text in front of my post in the blog was not the case with my car when you consider the first UJoint behind the steering wheel.
The job of the correctly connected cardan shafts is that the angular speed vs. the torque are evenly balanced/compensated so that the movement is smooth at any point of turning the wheel. For this reason the movement is always even, regardless of whether the forks of the first shaft are aligned exactly horizontally when the wheels are running straight. 

I hope I am able to write this in a reasonably understandable way. 

On the other hand it is not a deterioration if you pay attention to the alignment of the Ujoints when the wheels are running straight. Maybe there is something I didn't pay attention to. But I think it should not make a difference. The important thing is that the Ujoints are all correctly connected to each other as a whole system, regardless of any initial alignment in terms of wheel position.

Edited:
(When I took the photos of the first and second Ujoint the front wheels were not exactly straight ahead. It was a coincidence that the forks were horizontal).
.............................................

Heinz own original comments were as follows:

Now the steering functions is largely smoothly and evenly. I thought about the fact that due to the height adjustment of the steering wheel there must still be a Universal Joint in the driver's compartment. 

This Universal Joint is existing and it was not in line with the connection of the second shaft. Here there is no forced guidance of the two shafts. So you can put them together wrongly twisted if you do not care.

The First Universal Joint located behind steering wheel.


[Linked Image]

Together with this second UJ the forks must be in line.

[Linked Image]

The following shaft has twisted forks and this must be the case because it is a combined W-Z configuration.

With this shaft, its twisted forks are deliberately forcibly guided - pressed at one end and at the other end on a rail that dictates the centering, you can't go wrong with this shaft performing its function. 

See picture 3 below.
[Linked Image]
I hope that the need to get the UJs properly aligned is fully understood at the factory, but wonder if this makes its self through to QC?  I assume easily missed during build.
Here is the Full Explanation.


This „twisted forks“ shaft is connected to the last shaft which leads to the steering gear. 

This connection has to be adjusted again so that the forks match (in other words also here you have to pay attention to the same fork orientation because it is freely rotatable when you plug it together).

I suspect that the factory did not pay attention to the alignment of the fork of the first shaft from the steering wheel to the fork of the second shaft. 

That's why the peaks of the force which lead to increased wear and tear. You just have to connect it correctly and at the end you have to put the steering wheel in a new alignment. 

Now I am happy. It is worth to check the alignment if you think you have an edgy steering feel.

Here is Some Mathematics re The Shaft Angles.


I don't want to imply it, but it's possible that they didn't think about the consequences of not aligning shaft 1 to shaft 2 when they added the adjustable steering wheel height about 12 years ago or so. 

Before that there was no need to pay attention to the first shaft. Or it was just bad luck in my case?

Heinz.

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