Gumdrop on the Rally (Piccolo Books)

One day the Red Lion Car Park was full of vintage cars. It was a car rally and one of the cars was blue with a black hood. It was Gumdrop, driven by Bill McArran, and he had his number 9 on the front. Bill was driving down a country lane when a young man told him to turn left-- the wrong way.
When Bill and Gumdrop became lost down the country lane they found a little boy who was also lost. They took him home to the farm and the farmer gave Bill a can of oil as a present. And so it went on --- they helped a girl get her horse to the jumping competition and received sparking plugs as a present, they got an instruction book from the Mayor, vintage tools from a farmer, and a vintage petrol can. All for helping people.

Suddenly a motor bike, driven by the young man, skidded and a parcel fell off---- he had stolen the prizes for the rally. Bill returned them and although they did not win the rally they received all the presents and were awarded a brass starting handle for their kindness to other people.