Make sure soil is cleaned off any used equipment recently purchased from areas known to have clubroot. This is good biosecurity practice. Ideally, this should be done at the purchase location before bringing it home.
Clubroot spreads with the movement of contaminated soil, and the most common way to transfer soil from field to field is on farm machinery and vehicle tires.
Buying used equipment from a clubroot area can create an unexpected transfer of the disease. This is true for tractors, drills, combines and really any equipment that can pick up soil.
Also check that the transport truck is clean. As a precaution, you may want to pressure wash the equipment again when it gets to your farm. Do this in a commercial truck wash or on the farm in a low-traffic grassed area away from any cultivated soil.