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Eliminating the backlash on worm steering gear box equipped in VW Air-cooled Beetle 1302 has changed it's character completely. Most of old Beetle on the street, very seldom to meet with, are driven so slowly at the lowest speed lane, it looks dull, heavy and muddy attitude it does. My driving style was similar with it till the day before yesterday.
Wheel alignment and axle construction were not established enough to drive in witty condition, also backlashes scattered everywhere in connective portion contributed to inhibit positive driving.
To tell the truth, it shame to describe like this, 3 and a half screw in on worm gear steering gear box adjusting screw caused dramatic revolution in my Beetle. Long lasted chronic disease, "Lesion", has removed and the patient has acquired her innate healthy condition.
From the beginning it has been given up her sloppy character because of steering box construction, it is different from astute and sure rack and pinion design. But adjusting backlash into minimum has proved that my shallow idea was not to the point.
What's next, yes, the task is waiting for me, the lack of grease lubricant is felt on steering universal joint needle roller bearings. Following my memory, the fuel tank removal procedure might be required to access to the point?
She keeps tying me down for long period of time scattering anxieties continuously, the self-ascertaining character resembles that of my Xanthippe.

1.5 mm toe-in application on VW Air-cooled Beetle 1302 solved all the problems in steering reaction.
As I mentioned yesterday, a slight front side slip was corrected inviting the method that came out like flash. In order to know the side slip amount, piled sheets of paper utilizing unused old rectangular calendar. Careful checking on the corner edge after passing tire tread, the conformity there changes into slipped form like a fault slip as shown in the picture. To the out side means side slip to opening direction contrail inside is closing toe. Though this method looks primitive and child forgiveness, actually is practical and useful enough to adjust side slip in precise.
linear and comfortable steering reaction was obtained when the vehicle passed the same winding road experienced before.
Steering center stability is established now, but another problem has relieved, steering center position deviates and fluctuates.
Steering linkage including worm gear box backlash has some excessive hysteresis phenomena, so gear box backlash must be eliminated immediately. As this task is not so difficult so the adjustment would be done fairly.
A driving feel of my Beetle 1302 becomes good to better day by day.

There exist many barriers and difficulties to measure wheel alignment and axle construction for ordinary person who do not have Special tools and devices and most of the people will give up to do by ourselves at all. Wheel alignment tester machinery is expensive and it is difficult to handle and master it. This is why this specific field "Alignment" is ignored and regarded as the things impossible.
It is true that my imagination might be too childish and too primitive to measure and adjust the difficulty.
Remember that the Principle and the Aspect of change in Scientific field do not fluctuate so far as it happens on the Earth.
But the ideas of Trigonometric function and Pi would solves this Chronic problems to be cut in.
In addition, some principles of the Physiologic property of Viscoelasticity that is contained in the rubber material and lubricant.
Also the idea and understandings are required, Hysteresis phenomena of them and co-efficiency of friction between the tire and the ground surface.
Manufactures defines the tolerance in wheel alignment and axle construction based on the datum through their experiments and developments.
My intention is to minimize the assembly tolerance and the put them at the centric position.
Most of the challenger might give it up and run away to his tent, but the satisfaction when it is accomplished is above words.
Though my car is old with many clutches, dents and color balds, I never have any inferiority complex if some newly sophisticated, shiny and expensive one comes across to me. Because mine is well adjusted and well maintained by myself in no relation with external appearance.

Unfriendly front camber on VW Air-cooled Beetle 1302 was revised today spending all day. Very slight discomfort was felt since last time, it was possible to ignore but I dare scaled and corrected into some reliable condition. As I imagined, left camber value was not enough, 5 minutes and that of right side was 25 minutes, both of them was negative in stead of the datum sheet, 60' plus 20 ' minus 40', so I determined to align the left with the right value.
Remember that some change of camber causes toe-in value excessively, so camber inclination should be adjusted in combination with toe-in at the same time, vertical and horizontal fluctuation. The difference of linkage position of them are the reason.
In case of front tie rod construction like Beetle 1302, Toe-in value increases if more inclination is applied, in opposite case, rear tie rod car like Golf GTI Mk7 toe opens if it is done. Simultaneous adjustment is required in the scenery in addition to Side slip reduction also.
It is a troublesome and tiresome muscle work at all, because we must move the car forward and backward by human power not by engine power. Discrimination of artifact is the reason.
Releasing the internal stress between tire tread surfaces and ground is the first important item. This trifle but indispensable procedure must be spotted with no argument even if some it is done on the latest style wheel alignment tester machinery.
Consequently, it took me all day long to accomplish the negative 25' on both front wheels.
Changing the negative camber condition invites the thrust angle discrepancy as a matter of fact.
Establishment of "Zero Thrust" is done at any rate even on VW Beetle in spite of malleable steering construction is designed in the past.
My energy and intention are dried up today, so residual procedure to carry out "Zero Thrust" would be performed tomorrow.

I did not know what will happen if "Zero Thrust" is established in wheel alignment of vehicle until I have the experience actually. I could do that after eliminating all the artifacts preventing me to do. It took me as long as 20 years of period to know the results shown as below.

Driving impression under "Zero Thrust".

The vehicle goes straight without influence by the external disturbance from the tire tread surfaces.

Though the rudder pressures caused by the road inclination is felt and watched on the steering wheel, the vehicle does not change the running direction.

And the vector direction could be kept if the steering wheel is held firmly at the center position.

The steering center position while running is established automatically and tightly not by the driver's will but by the "Zero Thrust" characteristic condition.

Once upper center condition might be changed in coming across the turning phase, the transition to turning scenery is very natural and smooth, just pleasant and fun.

The information of the road surface condition, roughness and inclination from every tire tread is watched and felt independently through the steering wheel pressure.

It is not always necessary to keep straight running, just keeping at the center position is enough.

Because the vehicle does not change the direction, no excessive steering turning adjusting is necessary in "Zero Thrust" condition.

"Zero Thrust" vehicle will increase the number to run about as the driver's unconscious action, and any desire to replace it into new one will not spring out however sophisticated and fascinating newly designed model might be flicked by the manufacturers.

Warning here, the tendency to keep the same vector direction straight often causes sleepy, the phenomena resembles recent Lane Keeping system. This is why sleepy awake system is sold as a pair, I wanna put an emphasis on this point here.

Notes:

All the wheel alignment and axle construction scaling and adjustment is performed under the condition of physical property with plastic deformation and history phenomenon, "Hysteresis".

So, releasing all the internal stress is indispensable at all. There exist many compliance bushes and mainly hub bearings including lubricating grease that has viscoelasticity.

Moving the car forward and backward action by hand with a human energy is necessary for releasing internal stress not only the specific wheel but for all wheels, unleashing each other's tension.

Remember here, moving with motor and breaking is inhibited in this scenery. However hard task it may be, this employment must be done only by hand's action.

As a natural phenomena, scaling terminal point displaces as a matter of fact, the scaling board should be moved adequately in every scaling and adjusting phase.

Accumulating every step is the key to success, even a hand cut or omitting crucial step will cause error leading to failure and the lasting piled efforts will be in vain. Let's start from the beginning.

Pay attention on the weight distribution in the car as German Opel specifies to put 60 kg weight on the driver's seat while wheel alignment adjusting, depending on the most likely possibility of the specific condition.

Weight distribution is important because it affects on the datum within the range of few minutes angle value. The error caused by some different weight distribution is not ignored.

European Safety Standard specifies the tolerance of "Thrust Angle" withing 10 minutes angle value, so to speak "Allowable error". The vehicle specified within the value and one with establishment of "Zero Thrust" are in a different dimension.

As a recent sophisticated modern vehicle is fully computerized and the user is not permitted to enter inside now, so reducing and minimizing "Assembly tolerance" is the only residual way to concern ourselves with our own car deeply.