Like an Army executing a pincers movement, the trucking industry is closing in on the Maryland legislature, one of the last barriers to the unobstructed movement Florida and the Northeast.

Bourbon, beef and the backslap are a part of the arsenal aimed at raising the maximum weight limit in Maryland from 73,280 pounds. Directing the effort is Albert J. Mascaro, executive director of the Maryland Motor Truck Association.

Last night, about half the members of the House Ways and Means Committee, which will vote on the measure Wednesday, were Mascaro's guests for prime ribs at Deze's Restaurant on the Chesapeake Bay.

Even in Annapolis, where dinner and drinks are among the most common lobbying tools, the timing of Mascaro's dinners has raised a few eyebrows this year.

On Feb. 23 Mascaro entertained about half the members (and their spouses) of the House Environmental Matters Committee at Deze's. The next day, by a vote of 11 to 9, that committee rejected a bill vehemently opposed by Mascaro that would have required dump trucks to cover loose loads that fly into motorists wind-shields.

"Coincidence," said Mascaro. "The dinner was set up weeks in advance. I have no control over when the committee votes."

Two other major events sponsored annually by the truckers are its women's auxiliary's Salute to the Legislature and the association's annual convention.

The former, held each January for the last four sessions, attracted 546 people this year, including about half of the members of both houses of the General Assembly, their spouses, friends and staffers.

The convention is not quite such an out-front lobbying event, and Mascaro is more reluctant to talk about it. Until he became head of the association in 1970, the truckers met each summer in Ocean City.

But believing that "it only costs a nickel more to go first class," Mascaro moved the conclave to Bermuda in 1971. In succeeding years, it has been held in Las Vegas, Acapulco, Williamsburg and this summer, in Freeport, the Bahamas.

The association charters two airplanes, and includes in the cost to its members enough money to pay for the trips of several legislators who, in return for the free ride, are asked to make a speech or participate in a panel discussion.

Few legislators will talk about the trips - some say they have rejected the offer - but one who accepted was Del. Edward J. Dabrowski Jr. (D-Baltimore), who subsequently asked mascaro for a job, and got it.

Mascaro admits that this employment of a legislator is "lucky," but Dabrowski defends his right to hold the $15,700-a-year position as Mascaro's top assistant.

"I don't vote on any bills related to trucking," said the 41-year-old Democrat from East Baltimore.

The lobbvist and legislator were having a drink after a meeting about revising truck routes through Dabrowski's 43d legislative districts when Dabrowski told Mascaro, "You know I'm looking for a job." Mascaro recalled that he knew that Dabrowski was unemployed, but noted "You're a legislator. That's touchy."

After reviewing a resume form Dabrowski (BS, University of Baltimore, former sales representative), Mascaro got approval from his own board of directors, checked with the General Assembly's Ethics Committee, the Senate president and the House speaker, and decided to hire him over 10 other applicants.

Mascaro then sent a letter to all of Dabrowski's fellow lawmakers, outlining Dabrowski's duties and assuring them that Dabrowski would refrain from voting on any bills affecting the trucking industry.

Dabrowski took the job in October, 1975. His biography in the current Maryland Manual lists his occupation as "public relations director."

The "sole purpose" of the dinners, Mascaro said, is "for them (the legislators) to get to know me and me to know them and for them to know I'm being as honest and candid as I can. It's a confidence-building exercise."

While Mascaro said the dinners are "not conducive to discussion of specific legislation," Ways and Means Chairman Benjamin Cardin (D-Baltimore), who attended last night's dinner, said "Sure, he (Mascaro) talked about his bills . . . especially House Bill 1223 (the weight bill). That's the big one."

Mascaro is a skillful lobbyist (he prefers to be known as a "legislative agent") who leaves little to chance. For this most important legislation, he lined up some of the most powerful legislators in the House: Majority Leader John S. Arnick (D-Baltimore County); Appropriations Chairman John R. Hargreaves (D-Caroline); Assistant Majority Leaders B. W. (Mike) Donovan (D-Prince George's) and R. Clayton Mitchell Jr. (D-Kent) and Minority Leader William M. Linton (R-Baltimore County).

In his talks with legislators, either informally at dinner or over a drink, or formally as a witness at committee hearings, Mascaro says he stresses the reasonableness of his request. Since 1975, when federal law permitted 80.000 pound trucks, 35 states have increased their limits to that figure, and the failure of Maryland to conform not only blocks movement of the heavier trucks along the East Coast, but denies the state needed revenue. (The fact that fees to the state would be increased $3 million to $4 million annually if greater weights are permitted has caused Cardin to lean in favor of the bill.)

Maryland and Pennsylvania now block the movement of the heavier trucks. The motor freight industry is concentrating on Maryland this year because its rival lobby, the railroads, defeated a similar proposal in Pennsylvania last year.

The weight bill is Mascaro's primary interest this year, but he is following a total of 27 bills that would affect his industry. Killing bad bills, Mascaro confides, is a important as passing good ones.

"If I'm not available to explain to these people - I don't know what kind of industry we'd have," Mascaro said. "It's a very complex industry, and very little goes on that doesn't affect us. A seemingly simple bill could have disastrous impact."

Mascaro said his dinners are not forums for influencing legislators on specific bills. That comes, he said, in the hallways, where, "because they know me, they buttonhole me" and ask about pending legislation.

Mascaro, Dabrowski and three other employees produce a monthly magazine, TK, and keep the association's 397 corporate members informed about intrastate and interstate regulations that affect the industry. Mascaro knows a lot about interstate commerce because he worked with the American Trucking Associations in Washington for 14 years before taking the Maryland job.

About $12,000 of the association's $140,000 annual budget is spent on lobbying in Annapolis. Records filed with the secretary of state showed that the truckers spent $10,314.71 during the 1976 General Assembly, including the rent of an office shared with the Farm Bureau, and the cost of the a room at the Hilton for Mascaro.

But the bulk of the spending went for those old lobbying standby, food and drink. Mascaro's favorite way of "getting to know" a legislator is over dinner and drinks.

His 1976 expense report showed that Mascaro spent $733 on winning and dining individual legislators and $2,698 for group dinners. He reported spending another $1,000 on "gifts and contributions" to legislators.