An insurgent slate of Teamsters Union members, running under a reform banner, has toppled leadership of the largest local in the Washington area in an election seen by Teamsters dissidents around the nation as a significant breakthrough.

All 13 members of the dissident ticket, led by Daniel George, an outspoken critic of the local's leaders, swept to victory over a slate headed by Frank DeBrouse, incumbent president of Local 639. In the contest for president, George beat DeBrouse, 1,450 to 868. Ballots were cast by mail and the vote count ended last night.

The local election had been viewed by members of PROD, Inc., a dissident Teamsters group, as a chance to throw a national spotlight on insurgent Teamsters campaigns through an upset in a key local in the nation's capital.

"We intend to make as much hay of it as we can," Arthur L. Fox, PROD's counsel, said after Local 639 results were announced. Fox said only one other comparable group of dissidents has remained in power after unseating a local union's leaders - in Little Rock, Ark.

Among those elected in the Local 639 vote was John D. Catlett, insugent candidate for secretary-treasurer who was among three dissident Teamsters filing charges with the union's national executive board in April, seeking removal of Teamsters President Frank Fitzsimmons.

George and other members of his slate were at pains last night, however, to characterize their victory, as purely a local triumph and to draw a clear demarcation between their ticket and national dissident groups. "We have a responsibility to the members of Local 639 and only Local 639," George said. Nevertheless, he added that he has similar reformist aims as PROD.

As the ballot count was nearing completion, DeBrouse ordered a Washington Post reporter out of the Teamsters local office, saying, "Shove off." He then turned to several supporters and said, "Why don't you go remove him please, gentlemen."

George said later that DeBrouse had told him he would protest election results and not permit George to take office immediately, as George said was required by the union's constitution.

National Teamsters spokesmen could not be reached for comment.

Dissident members have been attacking the national Teamsters leadership, accusing it of misuse of funds, corruption, nepotism, links with organized crime and other charges. The national Teamsters leaders have generally dismissed the dissidents as a tiny fringe group with little significance.

They, nevertheless, appear to have mounted a serious response to dissident efforts to oust Fitzsimmons.

In the Local 639 contest, George and his slate denounced incumbent local leaders as undemocratic and allegedly cozy with management of firms where union members are employed. George said last night that these complaints as well as a series of bread-and-butter issues played a significant role in his victory.

He also said that he himself was better known among union members than he had been in several earlier unsuccessful election races and he described his campaign as more organized that in the earlier attempts.

Before votes were cast earlier this month, DeBrouse said he was so confident of victory that he had not campaigned. He asserted that his record showed solid gains in contracts and benefits for union members - a contention the dissident slate disputed.

Local 369 claims to represent more than 7,000 truck drivers and others employed at the Safeway Stores and Giant Food supermarket chains, United Parcel Service, the Washington Star and a number of local moving, cement and liquor companies.

For George, 41, yesterday's victory was his first election success in six years of trying to oust leaders of Local 639. His earlier efforts had led to protracted proceedings by the Labor Department and in the federal courts, including two U.S. Court of Appeals rulings.

He also was fired from his job as a truck driver at Jacobs Transfer Co. in 1971 as a result of his dissident union activities and has carried out a long fight through the National Labor Relations Board and in the courts to gain reinstatement.

He has regained his job, though the dispute is still pending before a federal judge. Local 639 has been his apponent in his job battle.

George had been defeated by DeBrouse in an election for union president in 1972. The results were later thrown out by a federal judge, who ordered a new election. In the rematch, however, George lost again and his subsequent court protest failed. He was also defeated in a race for union business agent.

One of George's court battles led to what some labor lawyers described as a significant U.S. Court of Appeals precedent for dissident labor groups.

The court ruled that when a union election is set aside because of irregularities, a dissident group's legal fees in the court proceedings may be paid from the union's treasury. The decision, several lawyers have said, will help get legal counsel for dissident labor groups, which often lack funds to pay legal help.