Steering rumbles while driving! Help !!!

[V8Germany]

Hi Forum,

I'm in Germany and own a Modell 68 Fordor Sedan from 1936.
Car just got full approval from german Technical Control Board.

This morning we did the Maiden trip...1 mile...

Then suddenly the steering started rumbling, the front of the car
was shaking/ vibrating and the steering felt soft and with no connection
to the wheels.

The vibrations stopped when I slowed down, but came back, independent
from the speed.

Air pressure in the tyres ok, tyres seem to be fix.

The rumbling was as strong that I nearly did not dare to drive home.

And idea, help ?

See pics