Newton I. Steers Jr., the wealthy former Montgomery County congressman, will be Republican gubernatorial candidate Robert A. Pascal's running mate, informed sources said yesterday.

Steers, 65, the outspoken millionaire businessman and Pascal, 47, once seat-mates in the state senate, met yesterday over breakfast at the Ramada Inn in Lanham after a week of negotiating through intermediaries. The two men reportedly talked for about an hour and at the end of the conversation agreed to join forces. The formal introduction of the Pascal-Steers ticket is expected Wednesday.

"You can say that Newt Steers is under very serious consideration," Pascal said when reached at home yesterday. "We have only very recently sat down and talked about this for the first time. I expect to make an announcement quite soon."

Steers said yesterday, "I can certainly confirm that we met and discussed a number of possible candidates. I suppose I might drop around Wednesday and see which of those fine candidates has been chosen."

Sources in the Pascal campaign said that Steers -- who was the fourth person given serious consideration for the job -- was chosen to try to strengthen the ticket in the Washington metropolitan area and because of his background as a successful businessman, something Pascal will emphasize in explaining why he chose Steers.

Steers, whose name first was suggested to Pascal in March by his long time friend, State Sen. Howard A. Denis (R-Montgomery), emerged as the leading candidate for the spot on the ticket after three people, Baltimore County state's attorney Sandra O'Connor, Montgomery Del. Constance A. Morella and former U.S. Attorney George Beall, told Pascal they were not interested in the job.

Nine days ago, Pascal pulled Denis aside at a political function to ask him if Steers would be interested in running with him. Denis contacted Steers that night and the negotiations opened, culminating in yesterday morning's meeting.

"If it is Newt Steers, then I'm excited," said party chairman Allan C. Levey. "I'm sure Bob realizes this election may be decided in Montgomery County and Newt would certainly strengthen the ticket there."

Wednesday's announcement will rekindle a political career thought finished two years ago when Steers was beaten soundly by Rep. Michael Barnes (D-Montgomery) in a rematch of the close race Barnes won in 1978 by unseating Steers after one term in Congress.

That loss seemed to finish Steers, who was appointed state insurance commissioner by then Governor Spiro T. Agnew in 1967 and served for six years in the state senate before his election to Congress in 1976. During his two years in the House of Representatives, he compiled the highest liberal voting record of any Republican. According to a study done by Americans for Democratic Action, he voted on the liberal side of issues 90 percent of the time, the 14th highest liberal rating in the entire House.

Ironically, in his narrow loss to Barnes in 1978, one of the Democrats' themes was that Steers was not liberal enough for Maryland's affluent Eighth Congressional District. Steers ran for his old seat again in 1980, defeating Morella by eight points in the primary before Barnes beat him with 59 percent of the vote in the general election. After that loss, many Republican regulars lamented their decision to go with the old guard -- Steers -- rather than a new face like Morella in the primary.

Steers, a graduate of Hotchkiss, Yale and Yale Law School and a one-time Army meteorologist during World War II, became a wealthy man after he and a friend had formed the Atomic Development Mutual Fund. In 19 months, they had sold $44 million in investments.

When atomic energy's rise halted in the 1960, Steers sold out of the business in 1965 and ran unsuccessfully for Congress the following year. In his last campaign Steers loaned $80,000 to his own coffers. Pascal's financial advisers are hoping some of the Steers wealth will be directed their way since the Republican has raised only about $200,000, less than half the total Democratic incumbent Gov. Harry Hughes has raised at this point.

The presence of Steers on the Pascal ticket will give it a decidedly moderate-to-liberal viewpoint, more liberal in fact than the Democratic ticket of Sen. Harry J. McGuirk and Lt. Gov. Samuel W. Bogley. That may alienate the more conservative factions of the party but, without a primary, Pascal is far more interested in attracting moderate Democratic voters than in worrying about conservatives.

Both Pascal and Steers favor Medicaid-funded abortions, although Pascal only believes in abortion when the mother's physical or mental health is endangered.

Pascal is trying to portray himself as a pro-business, pro-labor candidate, a difficult combination. With his own blue collar background (he grew up over a bakery in New Jersey), Pascal has proved appeal to labor groups in Baltimore. Steers, with his Montgomery County and business backgrounds, is expected to give the ticket appeal in white-collar Montgomery County. The thrust of Pascal's campaign thus far has been Hughes' "indecisiveness," and the articulate Steers will be expected to hammer this point, especially since the ideological differences between the tickets are minimal.

The introduction of Steers as the lieutenant governor candidate on the ticket will come a scant six days before the filing deadline. When he first announced his candidacy in February, Pascal said he wanted to avoid the kind of situation Hughes got into four years ago, when after being turned down numerous times, he chose Bogley at the last minute.

As the weeks slipped by, it became apparent that Pascal was not going to announce his choice quickly. "I want to wait until after Harry does his," Pascal said early this month. Hughes introduced Sen. J. Joseph Curran Jr. as his replacement for Bogley on the ticket on June 11. Four days later, Bogley joined McGuirk.

Pascal would have liked to have followed swiftly with an introduction of Beall, but the brother of former U.S. Sen. J. Glenn Beall Jr. would have had to take a large paycut from his law practice to become lieutenant governor at $62,000 a year. He told Pascal intermediaries he did not want Pascal to ask him to run. When Pascal and Beall posed for a picture at the opening of Pascal's Baltimore headquarters, someone asked if that was the ticket. "I wish it were," Pascal said wistfully.

"Whoever I choose, it has to be someone I'm comfortable with personally and compatible with on issues," Pascal said yesterday. "It is not unfair to say that Newton Steers meets those criteria."