The Chicago City Council’s Black and Hispanic caucuses are prepared to merge their political muscle to demand that minorities get their fair share of the bonanza of jobs and contracts triggered by a proposed $8.5 billion O’Hare Airport expansion project, an influential alderman said Friday.

Two years ago, the City Council came within one vote of blocking a $3.5 billion O’Hare Airport bond issue, delivering a powerful message about the lack of minority participation on the airport gravy train.

At the time, Ald. Roderick Sawyer (6th), chairman of the Black Caucus, warned that future alliances between the Black and Hispanic caucuses could someday create a political roadblock that would force Mayor Rahm Emanuel’s hand.

On Friday, Sawyer issued a similar warning about the $4 billion borrowing Emanuel wants aldermen to authorize to start the ball rolling on the O’Hare expansion plan that American Airlines stands alone in opposing because of a dispute about five additional gates being awarded to hometown United.

“We almost stopped one once before. So that is one way” to leverage job and contracting demands, Sawyer said.

“We want to make sure this process is truly fair, and we’re not getting shafted or inundated with promises and nothing fulfilled . . . We want more than just promises. We want something that’s enforceable.”

Together, Blacks and Hispanics comprise roughly 66 percent of Chicago residents. Sawyer acknowledged that demanding 66 percent of the jobs and contracts at an expanded O’Hare would be a “tough ask.”

But he said, “Our goal individually and collectively is to make sure that we’re not ignored in this process . . . We want contracting to look more like the city. We want it to be reflective of what the city’s demographics are.”

The Black Caucus has 18 members; the Hispanic Caucus is 11 aldermen strong. Together, they have the 29 votes needed to block the O’Hare expansion plan and the $4 billion bond issue needed to get it started.

Sawyer acknowledged the last thing either caucus wants is to stop the gravy train from leaving the station.

“That would be cutting my nose off to spite my face,” he said.

Where then is his leverage?

“They need the bonding authority to get started on the work. These are things we have to look at to make sure we’re doing what’s right for our constituents,” he said.

Earlier this week, the Hispanic Caucus demanded five years worth of hiring and contracting information from both United and American Airlines that will be used to determine whose side to take in the high-stakes battle over new gates at an expanded O’Hare Airport.

Ald. Gilbert Villegas (36th), chairman of the Hispanic Caucus, made the demand during closed-door, back-to-back briefings with both carriers searching for City Council allies in their high-stakes dispute over gates at an expanded O’Hare.

The Black Caucus is scheduled to meet Monday with American and United. The airlines want to talk about gates, while the aldermen want to talk turkey about jobs and contracts.

“I don’t want us to be deflected by the gate issue. I don’t want that to be the end-all, be-all. The real important issue is the teams they’re going to be picking, the complexity of those teams, and how it’s going to benefit the black community and the Latino community,” Sawyer said.

“We want to make sure the numbers they’re talking about are floors — not ceilings. If they’re talking about 30 percent, we want the numbers to bust out of that . . . We want to make new millionaires. This is an opportunity to get more people in the craft trades, construction business, professional services, engineering, lawyers, bond underwriting. Everybody can do well when you’re spending this kind of money.”