The steering was one of the factors that persuaded me away from the Isetta. It is a design with many links that can be a issue and to cap it all the caster action is a bit odd. Some cars have dampers to control steering wobble. They tend to have that 50's film steering. That is not to say it cannot be set up but it is not a simple assembly. I bellieve there are several differing worm sets to if you are tempted to change parts but I am no expert.
Messerschmitt set, Goggo Darts, Heinkel 175, Vellam Isetta, Fiat Jolly, Peels, Bamby, AC Mk12C & Type 70, Velorex, Church Pod 1, Reliant Mk5, Bianchina Cabriolet
MG ZB Varitone, Wolseley 4/44, Borgwards, Saab 96s, Bellamy trials, Isuzu Trooper, Citroen BX 14E, 16TRS Auto, 17TZD Est & Sal, GTI 16V