A small coalition of McLean parents is launching an 11th hour effort to prevent the demolition of their neighborhood elementary school's original section.

The six or seven parents actively fighting to save the 52-year-old wing of Chesterbrook Elementary School on Kirby Road are racing against the clock, since the school board is expected to let the demolition contract June 29. The wing is due to be torn down to make way for a new school gymnasium.

The school board in January approved Chesterbrook renovation plans that included building a new gym where the old wing now is located in the front of the building. The entire renovation is expected to cost $422,300.

Those fighting the demolition, who say at least two dozen McLean families support their work to save the wing, say the original section is worth keeping for its historical value and claim it could be used to house community activities or educational functions.

Chesterbrook's PTA President Mary Collier is concerned, however, that any delay in renovation while a community group is found to rent the building might endanger Chesterbrook's future. Renovation currently is scheduled for this summer.

Collier said Chesterbrook could be studied for closing if the school board next month adopts recommendations by a citizen task force concerning school closings. The report recommends a school be studied for closing when it is scheduled for major renovation. In addition, the longer Chesterbrook waits to spend the renovation money, the fewer repairs and additions it will buy, she said.

"If we keep dilly-dallying around we won't get the renovation, we won't get the gym and we might not get the school," she said.

School officials say it is too expensive to keep the original wing, estimating that it would cost more than $100,000 to restore it. They also claim Chesterbrook will have too few students to justify keeping the older section of the building, because its enrollment is expected to fall to 211 students by 1983. Chesterbrook now has about 476 students, but the school has space for 570.

"I guess I'm just conservation-minded, but I hate to see things just thrown away," said Pat Franklin, a Chesterbrook parent and a leader in the effort to save the wing.

School board member Nancy Falck, who represents the Chesterbrook area, said any group that wanted to use the wing would have to pay for the renovation as well as the costs of operation and maintenance.

"I'm open to alternatives that are economically feasible," she said.

The McLean Community Center, now considering expanding its existing space at 1236 Ingleside Ave., recently expressed interest in using Chesterbrook's original section. The center's board of directors is expected to discuss the matter at its Monday meeting, said Bernard Boston, board of directors chairman.

"It would cost us more than $80,000 to expand our own space, so its not out of the question that we would look at Chesterbrook," Boston said. "It's a darn shame to destroy it when there's a possibility of using it."

Franklin requested that the school board approve delaying demolition of the original wing with a special provision that the delay would not jeopardize the school's renovation money or the school's existence.