Montgomery County school board members, in an attempt to improve the process of increasing racial integration in the classrooms, called last night for more aggressive involvement by school officials in the drawing up of county-wide housing and zoning plans.

The recommendation was included in a six-page draft of proposed changes to the county's two-year-old policy on integration. Earlier this month in a previous draft, school officials also proposed lowering substantially the threshold at which the board may act to correct a school's racial imbalance.

The board currently is required to consider action, including busing, to alter a school's racial composition when the minority enrollment exceeds 64.1 percent. The latest proposal would lower that threshold to 45.4 percent. Minority enrollment in the county is now 25.4 percent.

During last night's wide-ranging discussion, board member James Cronin supported a more active role by the board in housing decisions and reminded board members that historically, racial isolation in the schools has been caused by housing patterns. His position won support from several other board members.

Cronin said some real estate agents have steered minorities to certain areas in the eastern and southern sections of the county where minorities make up more than half the enrollment in many of the schools. Such steering is prohibited by federal antidiscrimination laws.

Last night's proposals, which are scheduled for a vote Oct. 5, were a measure of how far the present board majority has distanced itself from the former school board, which caused a major protest in the minority community when it voted two years ago to alter a 1976 racial balance policy to include a higher threshold of 64.1 percent. At that time, critics said the board's action would create "educational Berlin Walls" around racially isolated schools.

Marian Greenblatt, one of two remaining members of the old board's majority, argued strongly last night for including in the policy a statement of support for "neighborhood schools"--a phrase Greenblatt has used frequently in her attacks on busing for integration purposes. If a school with a high minority enrollment is providing a good education, Greenblatt said, "it should be left alone."

Her proposal drew little comment from other board members.

Other proposals included requiring the board to consider providing more funds for schools identified as having special needs caused by higher minority enrollments and requiring consideration of the "diversity" of a school's minority enrollment when changes aimed at integration are proposed.

School planners now lump all minorities together when reviewing boundary or other school changes, but during the past two years of school closings a number of parents have argued that the different kinds of minorities in a school sometimes add to the racial balance rather than detract from it.