I forgot the name of a children's story about and grandfather and grandson who put back an old car from parts.?

My husband thinks it's a children's story from England about how a grandfather who has found parts of an old car he once owned that's been scattered in different locations in the area, puts it back together with his yound grandson's help.

I forgot the name of a children's story about and grandfather and grandson who put back an old car from parts.?
At first I thought it was Chitty Chitty Bang Bang but that was actually the father, not the grandfather, who put together an old race car that his young children loved to play with.





Best of luck to you. I'll check back to see if someone else knows!