Possible Clues:

• Managing directors on vintage car
• It's a job for company boss to get in old car, step on it
• Managing directors step on old vehicle
• Feature near the door of a really old car
• Step on car committee after contention
• Old auto attachment
• Going on foot was tedious, it's said - step on to vintage car
• Feature of old car company chairman's job
• Managing directors' old car part?
• Part of vintage car working, a pig to decoke at first