Parents of students who attend Fort Hunt High School tried to persuade the Fairfax County School Board last night that it needs their backing for a proposed bond issue as much as it needs to close the school.

In a bid to prevent conversion of Fort Hunt to an intermediate school, as proposed in a report from a citizen task force, a newly formed coalition promised to campaign for the county's politically vulnerable $74.8 million school bond issue that voters will approve or reject on election day.

In return, Peter H. Brinitzer, head of the newly formed Neighborhood Schools Coalition of the Fort Hunt Area, said he hopes the board will vote next year to perserve Fort Hunt as the neighborhood's high school.

Specifically, he said that on election day the coalition will assign an adult and a Fort Hunt student to distribute proschool bond literature at each of the county's 163 polling places.

The offer was made at a board meeting attended by about 50 Fort Hunt parents, many wearing bright yellow "Keep Fort Hunt Open" buttons.

The board had no reaction to the proposition Brinitzer outlined. But school officials said privately that the coalition's campaign may come too late to change the outcome of the referendum and that the board will decide the future of Fort Hunt based on the arguments of the school staff and on the reports submitted by the task force, which studied the problem of declining enrollment in the Mount Vernon area.

Fort Hunt High is in the southeast part of the county where enrollments have been declining steadily since the late 1970s.

The recommendation to close it as a high school upset the cohesive Fort Hunt community, which has been strongly allied to the school. In a week, the area's residents have built a political organization similar to one they had five years ago when they mounted a successful effort to have the school rebuilt after it was hit by fire.

After three meetings last week, about 400 Fort Hunt residents joined the coalition, Brinitzer said.

Since 1972, the Mount Vernon Magisterial District, which includes Fort Hunt High school, has voted against five of eight school bond issues, according to school officials.

Brinitzer said the area's voters would have to "overcome its natural opposition" to this year's school bond proposal.

"Why should we vote for millions of dollars in other parts of the county while we don't benefit at all and face the possibility that our school will be closed?" he said after the meeting.

But he said it was the "obligation" of the Fort Hunt community to campaign for the bond issue "if we expect cooperation and understanding from both the School Board and the Board of Supervisors," which appoints School Board members.

Brinitzer said the coalition has been divided into committees, each drawing on the particular professional skills of its members.

They include committees for fund-raising, mailings, poster designing, word-processing, community relations, and public speaking, and one composed of Capitol Hill lobbyists, Brinitzer said.

Superintendent William J. Burkholder said he will hold public hearings in the Mount Vernon area on Nov. 2 and possibly Nov 12 on prospective solutions to declining enrollment.

The school board will hold its own session in February and announce its decision the same month.