Republican presidential nominee Donald Trump spent much of August at high-dollar fundraisers. (Carlo Allegri/Reuters)

John Rakolta Jr. was skeptical as he headed to a private meeting with Donald Trump in July at Chicago’s Trump International Hotel. The Michigan construction executive, a longtime ally of 2012 GOP nominee Mitt Romney and a top fundraiser for Sen. Marco Rubio, was not yet sold on raising funds for Trump.

But the Trump whom Rakolta encountered in a suite on the 27th floor was nothing like the provocateur he expected. “He is extremely soft-spoken,” Rakolta said. “None of the stuff that I imagined.” The two had a wide-ranging discussion about why auto companies build plants in countries such as Mexico instead of the United States.

Rakolta left with newfound enthusiasm. Trump left with a new talking point.

“I have a friend who builds plants, and he’s a great builder of plants, and I was with him the other day — great guy,” the candidate told reporters a few weeks later. “And I said, ‘How’s it going?’ He said, ‘Unbelievable. . . The plants I’m building in Mexico, I’ve never seen anything — it’s the eighth wonder of the world.’ And he’s not happy. He’s an American guy. He’d rather build them here.”

The New York billionaire, who has cast himself as free from the influence of the party’s donor class, has spent this summer forging bonds with wealthy GOP financiers — seeking their input on how to run his campaign and recast his policies for the general election, according to more than a dozen people who have participated in the conversations.

Private meetings with top contributors turn into strategy brainstorming sessions. High-priced dinner fundraisers are transformed into impromptu focus groups.

During a July lunch at a Southampton, N.Y., estate, he spent at least an hour asking the 60 heavyweight contributors in attendance to each share their pick of whom he should tap as his running mate. At a photo line with donors in Minneapolis in August, he polled whether he should continue using a teleprompter at public events.

At a mountainside chateau in Aspen last week, he quizzed locals about how the campaign could better compete in Colorado. And in a pistachio orchard outside a supporter’s home in Tulare, Calif., this week, he queried farmers about how to create a “permit” system for undocumented workers.

The episodes illustrate how Trump, who has a tiny circle of intimates, is turning to the wealthy business leaders he encounters on the fundraising circuit to serve as an ad hoc kitchen cabinet. He appointed many of his biggest financial backers to his economic advisory council, including Wisconsin billionaire Diane Hendricks, investor Tom Barrack and oil executive Harold Hamm. And there are already signs of how Trump is incorporating ideas from donors into his campaign.

The most dramatic example came in August during a fundraiser in East Hampton, N.Y., when conservative benefactor Rebekah Mercer touted the merits of Breitbart News chief Stephen K. Bannon in a conversation with Trump about his campaign leadership. Days later, Trump sidelined campaign chairman Paul Manafort and effectively replaced him with Bannon.

Several days later, casino billionaire Sheldon Adelson privately urged Trump to show more humility and treat people with more respect, as the New York Times first reported. The next day, the candidate issued a rare apology for causing “personal pain.”

In a statement, Trump told The Washington Post that he has “met some really wonderful people while raising money for the RNC. They do also like that I am personally investing many millions in my own campaign. Some of the people I’ve met I’m sure will be lifelong friends.”

When asked about the perception that donors have input on his decision-making, spokeswoman Hope Hicks responded that Trump “is an excellent listener and welcomes the advice of people he respects.”

“It is a great leadership quality and reflective of his creative, bold thinking that proved to be so successful throughout his career,” she added.

In private, supporters see a side of Trump that sharply contrasts with his persona on stage at his raucous rallies. Solicitous and restrained, he disarms those expecting a bomb-thrower.

“I had heard he was a different person than you see in the media, but you don’t know until you experience it,” said Janet Beihoffer, a national committeewoman for the Minnesota Republican Party, who was struck by how engaged the candidate was during the photo line in Minneapolis several weeks ago. “I was floored.”

Over and over, donors said they were impressed by Trump’s attentiveness — he leans in close, moves his chair over, focuses only on what they are saying — as well as his intense efforts to glean new information.

“I had no idea what to expect, and I was very pleasantly surprised by how well he listened to what I had to say,” said Andrew Sabin, the owner of a New York-based precious-metals refining business, who met privately with the candidate earlier this summer in the Hamptons to assess whether he wanted to contribute to his campaign. “No arrogance, you know, ‘I’m Donald Trump, the king of the world.’ He sat back and wanted to know what your opinion was.”

The two men discussed immigration, among other topics, and Sabin said he made the case that it was impractical to deport the estimated 11 million undocumented immigrants living in the United States, as the candidate had insisted in the primaries that he would do through a “deportation force.”

Several weeks after their meeting, Trump set off a storm of confusion by suggesting that he was still assessing whether all undocumented immigrants would be subject to immediate deportation. Sabin was heartened. “I think he liked what he heard,” he said.

In a speech Wednesday in Phoenix, however, Trump renewed his hard-line call to deport undocumented immigrants, particularly those convicted of crimes and those who have overstayed visas.

Peter Leidel, a Texas-based energy investor, was impressed with how the candidate solicited ideas from a dozen donors at a breakfast fundraiser at Trump Tower in New York in early August.

“To every person who said something, he would ask questions and say, ‘Let me get this straight,’ ” Leidel recalled. “He would jot things down.”

When it was Leidel’s turn, the investor told Trump that he should do more to highlight Hillary Clinton’s “bad judgment” for supporting the war in Iraq and President Obama’s health-care overhaul.

Trump scribbled “judgment” in his notebook as Leidel spoke, a word he had used as a cudgel against his Democratic rival in the past.

The very next morning, Trump took up the attack again, tweeting: “Hillary Clinton has bad judgment and is unfit to serve as President.”

“I don’t know if it was me or not,” Leidel said of Trump’s tweet. “But I think listening is a very important skill. I think a lot of people pretend they are listening, and they don’t even care what you’re saying.”

Billionaire investor Wilbur Ross, who hosted Trump at his Southampton estate in July, described the candidate as “very relaxed, very low-key, and very, very good at including everybody in the conversation.”

“It’s a different persona from the one you see at the big rallies,” Ross said, “and much more like his persona when he is hosting parties at Mar-a-Lago or at one of his golf courses.”

Andy Puzder, chief executive of CKE Restaurants, said Trump’s style behind closed doors reminds him of how he himself conducts business meetings. “He says to the guys and gals, ‘So what do you think of this?’ ” Puzder said. “Whatever he is working on, he tries to get input on. That’s what I do.”

In one case, the restaurant chain executive recalled that Trump walked into a small group of donors gathered at Trump Tower in June and said, “Who do you guys think I should pick for vice president?” Indiana Gov. Mike Pence, his eventual selection, was among those discussed.

While Trump has reportedly little appetite for fundraising, he has kept up a busy pace of pricey events in August, headlining more than 20 receptions and dinner s, including some that cost up to $100,000 a couple, according to a tally of invitations by The Post. (Unlike Clinton, who was on her own fundraising spree in August, Trump does not disclose when he is attending fundraisers, who is hosting them or the minimum donation required.)

Each gathering serves as another sounding board. At an August dinner in Canton, Ohio, he quizzed about 30 donors at a local country club for their thoughts on local business issues.

“He would say, ‘How would you solve that? What would you do?’ ” recalled Doug Sibila, the chief executive of a warehouse and transportation company, who weighed in on what he views as onerous Department of Labor regulations. “As he shared some of his ideas and opinions, you can see they were in process, that he was willing to adapt based on what made sense.”

Their biggest regret, many donors said, is that more Americans do not get to see the private Trump.

People view him as “off the cuff, but I think he is actually very thoughtful and measured,” Leidel said. “He is not going to make a decision without listening to advisers.”

At the breakfast fundraiser at Trump Tower in early August, where he went into details about his approach to issues such as the war in Syria, attendees urged Trump to share more policy specifics in public.

“At the rallies, if I give much more than a one-word sentence, I lose the audience,” Trump responded, according to Leidel. “I want to keep their attention.”

Sean Sullivan contributed to this report.