For all Louet double treadle wheels, there is a wooden bar that links the two treadles together. This is called the "Rocker Arm" If this piece brakes - It can be replaced. The most common reason for the brake, is when force is applied to both treadles at the same time.
A new Rocker arm can be purchased and replace the damaged one.
Victoria Beech rocker arm part # - SR0161
Victoria Oak rocker arm part # - SR0162
S10 concept rocker arm part # - SR0160