Matthew Cowell races this Californian Retro Racer events rather successfully. The problem was that the original drum brake was needing new shoes and they were proving difficult to obtain in good quality material. His father Steve decided to have it converted to a mechanical disc system.
It just happened that I had a good quality Kart Component mechanical caliper in the workshop from the Sabre build. So I began the conversion which included modifying the caliber for two cable operation which is of course mandatory these days for safety!
Matthew has to carry 8kg of lead too make the weight so this had taken its toll on the seat too with the holes elongating in the glass fibre. This was rectified by riveting aluminium plates on the seat to reinforce it.