Parent activist Linda Moody yesterday defeated D.C. Board of Education member R. Calvin Lockridge, whose aggressive, outspoken involvement in school affairs over 12 years ranged from the corridors of central administration to the classrooms of the Ward 8 schools he represented.

Moody, a 41-year-old real estate agent, outdistanced Lockridge by almost 2 to 1 in the voting.

Jay Silberman, a leader of the group Parents United to Save D.C. Schools, won over 10 other candidates seeking an at-large seat left vacant by retiring board member Eugene Kinlow.

In Ward 4, Sandra Butler-Truesdale, president of Ward 4 Democrats, won election over 11 other candidates. She narrowly defeated the runner-up, Nathaniel Sims, for the school board seat that had been held by Linda Cropp, who left it to run for the D.C. Council.

In the two other races with incumbents, R. David Hall easily won reelection in Ward 2, and Nate Bush defeated four challengers in Ward 7 by a large margin.

The voting will reshape the 11-member board. Three new members will join a panel that is facing two significant challenges: replacing the school superintendent and carrying out the package of recommendations for educational change proposed last year by a group of prominent civic and business leaders.

The current board has battled frequently with Superintendent Andrew E. Jenkins over the pace and substance of the changes he was making in the 81,000-student school system.

In July, the board nearly fired Jenkins and announced that his contract would not be renewed when it expires next July. The current board hopes to pick a replacement by the end of December, in which case the new board, taking office in January, would have to deal with the transition to a new chief administrator.

Education activists expect the new board to implement the extensive recommendations of the D.C. Committee on Public Education, the civic and business panel that proposed wide-ranging changes in such areas as teacher salaries and training, school administration and programs and curriculum.

Lockridge, 57, had been an ally of Jenkins's, and he has come under criticism from some of those advocating the package of educational changes.

Last night, Lockridge attributed his defeat to the "cleaning house" theme that pushed Sharon Pratt Dixon from long-shot candidate to election as mayor. "There is the whole political fever that there is a need for a change," Lockridge said.

However, others said Lockridge's history in representing the city's poorest ward and the schools with the lowest academic achievement were key factors in his defeat.

"The people in our ward have sent a message not only to our board member but also to the District of Columbia that we were tired of all this mess," Moody said last night.

Ballou Senior High School, the only high school in Ward 8, was torn for several years by battles between Lockridge and the school's principals. In the last two years, principals have been transferred 24 times in the 23 schools in Lockridge's ward.

Lockridge has been beset by other controversies as well. One of his closest friends and a school employee, Michael Wheeler, was convicted on drug distribution charges. In 1988, cocaine had been found in the trunk of Lockridge's car, which Wheeler was driving in New Jersey. Lockridge himself never faced any charges in connection with that case.

Later this month, Lockridge is scheduled to be tried on charges that he punched the president of the D.C. Teachers Credit Union, an allegation that Lockridge denies.