R. Calvin Lockridge was elected president of the D.C. Board of Education last night after two other contenders broke a deadlock by withdrawing from the race.

Barbara Lett Simmons, one of the two contenders who withdrew, was elected as the board's vice president.

Their election drew together the majority and minority factions of last year's board, whose members often were at odds over educational and administrative policy. The clear losers were four board newcomers elected with the endorsement of Mayor Marion Barry.

Lockridge, who represents Ward 8 in far Southeast and Southwest, emerged as the leading compromise candidate at a closed caucus of most board members late yesterday afternoon at school board headquarters. The caucus lasted so long that the election meeting scheduled for 6:30 p.m. at Brookland School in Northeast began an hour late.

Lockridge received six votes, the simple majority of the 11-member board needed for election. Eugene Kinlow, the candidate of the Barry-backed slate, got one vote. When Lockridge's election was declared, the votes of the other four members -- which probably would have gone for Bettie G. Benjamin -- were not counted.

Last Friday the board became dead-locked after a series of 12 identical ballots in which former board vice president Carol L. Schwartz received four votes, Kinlow four and Simmons three. After six hours the members agreed to recess until last night.

Schwartz said she decided to withdraw shortly before last night's meeting when it became clear that she could not win and that Lockridge's election would keep control of the board's committees in the hands of incumbents and not the Barry-backed newcomers.

Simmons, offered the vice presidency, then withdrew her own candidacy for the top post.

The prsident appoints committees and their chairmen, presides over board meetings and serves as its spokesman.

Lockridge reminded reporters last night that he was the only current member of the school board who voted against renewing the contract of Vincent E. Reed as superintendent in 1978.

But, Lockridge said, he believed he could work smoothly with Reed, and would try to build bridges to the Washington Teachers Union. During last spring's teacher strike, Lockridge was part of the board's majority faction that opposed the demands of the strikers.

Simmons was part of the minority faction.

He also said he hoped to provide leadership that would unite the board's factions.

A 46-year-old native of Tennessee who once was a dock worker in Tampa, Fla., Lockridge was employed in pharmaceutical and oil marketing but left to join the civil rights movement in the late 1960s. He became chairman of the Black Consortium in Chicago, spearhead of the movement in that city.

Before being elected to the school board in 1977, he was director of the Anacostia community school project. He holds three master's degrees and is a candidate for doctorates in educational management and political science.

Simmons, 51, is a former teacher who heads a management training firm.

After Schwartz and Simmons withdrew their candidacies last night, Frank Smith, Jr., a new Barry-backed member from Ward 1, nominated Benjamin for the presidency. Kinlow also remained a candidate.

Voting was by a show of raised hands. When Kinlow's name was called only Nathaniel Bush of Ward 7 supported him. Lockridge was supported by Schwartz, Simmons, John E. Warren, Frank Shaffer-Corona and Alaire B. Rieffel. Benjamin's name was not called, and she did not vote, along with Kinlow, Smith and Linda Cropp.

Lockridge's presidential term is for one year. He succeeds Minnie S. Woodson, who did not run for reelection to the board in November.