WASHINGTON — There’s something about bulldozers and hard hats that brings a family together.

It worked for Donald Trump and his father. And it worked for Donald Trump and his children.

Long before Donald Trump was a presidential candidate, New York real estate mogul and reality TV star, he was Fred Trump’s kid, sitting at his dad’s knee playing with blocks as his father developed homes and postwar apartment buildings in Brooklyn and Queens.

Fast forward six decades, and Donald Trump’s three oldest children, all thirtysomethings, are vice presidents in his real estate empire as well as top advocates for their father in his presidential campaign.

Handed down across the generations was a clear set of Trump family values: work hard, talk big, sell luxury and leave your mark.

Like dad, Don Jr., Ivanka and Eric Trump were the boss’s kids before they were business executives and campaign adjuncts. They tagged along on their father’s visits to Trump construction sites and built Lego skyscrapers on the floor of their dad’s office as he negotiated hardball real estate deals.

“This is the third generation of builders,” Don Jr. once said. “I think we’ve been programmed genetically with too much ambition to sit back and collect rent for the rest of our lives.”

It’s not just a love for brick and mortar that runs in the family.

Fred Trump built his real estate business by dangling dreams of luxury living to the middle class and showcasing champagne-sipping “bikinied beauties” in the scoop of a bulldozer, as one old news clip recounted.

A Trump real estate ad from 1949 describes Fred as “acting as a free and rugged individualist to meet the basic need for shelter.” Many of his ads end with the tagline “another luxury achievement by Fred C. Trump.” Old news articles show him extolling the impressive lobbies of his buildings, the popularity of new space-saving efficiency units and special features of Trump properties such as free supervised day camp services for tenants.