Thanks so much for he really useful responses
Tom - did you just unbolt the single stanchion at the fwd end of the Genoa track ? And managed to move it first forward then outboard once the lower side flanges were clear of the toe rail?
if so I’ll try this first and will try to replace the cars completely 🤞
I will anyhow also fix my current cars as I need them now and good to have them in working order too.
Gerhard - it sounds like you just used a ‘push fit’ idea. So the Center hole on the new wheel was a tight fit to the 10mm pin. Then tap with a small hammer into place?
I might try this or ask for a slight shoulder on the pin - as per my sketch. So the lower half of the 10mm is just very slightly thinner than the top half. Say 9.5mm OD.
Combined with a stainless washer/wheel with a
Center whole of the same diameter (9.5mm) of the smaller section of the pin
the wheel would ‘push fit ‘ onto the lower
9.5mm pin section and be prevented from raising higher by the 10mm shoulder
the spring would sit above the wheel/washer as always.
It might just work!?
many thanks to all for the ideas and help on this 👍