When Montgomery County school board candidate Barry Klein returns to the South Bronx streets of his childhood, he gets worried.

Klein, a Potomac physicist, sees what time and neglect have done to the once-middle-class neighborhood of clean streets and good schools and wonders whether the same fate awaits Silver Spring.

"Nothing made me more angry than to hear members of the present board majority say that school board decisions affect only schools," said Klein, 40, a second-time candidate who lost in 1978. "It was a very empty-headed remark. This school board is dealing with a fictional city and . . . county that doesn't have a Rosemary Hills or Eastern Junior High School or an East Silver Spring.

"Downtown Silver Spring may be a long way off from the Bronx, but you only have to look there to see what happened when a city chose to ignore a large influx of minorities. It turned into mass chaos, a Dresden."

Like most of the 15 candidates vying for one of four open seats on the board, Klein takes the offensive when discussing the current conservative board majority.

He said the members' actions are not only an "embarrassment" but also short-sighted. He called their budget decisions not only illogical but "not cost-effective," and their relations with each other "so factionalized" that nothing is being accomplished.

Their decisions to close Rosemary Hills and change the attendance boundaries of Eastern Junior High and Montgomery Blair High in the heavily minority Silver Spring area were the result of "unmitigated gall," he said.

He called "a legal disaster" their most recent decision to go to court to fight the state board's reversal of their decisions affecting these three schools--actions that critics claimed would upset the area's and the schools' racial balance.

Like many of the candidates who hope to shed the conservative-liberal labels that have been used to characterize the current board, Klein considers himself a "middle-of-the-roader," a moderate who will be able to stick to dealing with issues rather than personalities.

"The current school board is so intent on bickering along conservative-liberal factions that the community is beginning to lose faith in their ability to govern," Klein said. He warned that if some shift toward moderation and cooperation is not made, Montgomery County may face a citizen revolt similar to that in Prince George's County.

In 1978, Prince George's voters approved TRIM, a measure that put a cap on property taxes, the largest source of revenue for local schools.

Despite his protests, however, Klein may run into difficulty with conservatives who will call his solutions to the county's racial problems too costly and will question whether his defense of the expenditure sounds suspiciously liberal: spend now and save later.

Among the ways he proposes to deal with the growing racial imbalance in the county is to strengthen the cluster programs in the Silver Spring area.

The clusters, which use special academic programs as magnets to attract white students, must be made more attractive, he said. And Blair High School must be turned into a strong comprehensive high school before any attempt is made to introduce a performing arts magnet, as Superintendent Edward Andrews has suggested, Klein believes.

Klein added that, in fact, he would ask for a review of the "entire lower county"--the closing decisions, the attendance boundaries and the academic programs.

Klein said he is ready to debate anyone who questions the costs of implementing his proposals.

"It is much more cost-effective to deal with the problems of the disadvantaged when they are in school, instead of when they get out and can't get jobs," Klein said. "And if any of the board wants to take a shot, I'd like to ask them how they can claim to be fiscally responsible when they are going to spend hundreds of thousands to fight the state board in court."

A surprisingly strong candidate in 1978, Klein finished fifth (four seats were filled) in a race that firmly established the current conservative majority. He ran as an independent then, but in this election Klein is forming a slate with Tim O'Shea and Vicki Rafel, two candidates with backgrounds in the Montgomery County Council of PTAs. The three will campaign against the actions of the current conservative majority and will advocate ways to implement new programs and make others stronger, said Klein, who works at the Naval Research Laboratory in Washington.

In the coming Nov. 2 general election, two of the four seats are completely open: those of Eleanor Zappone and Elizabeth Specer, who resigned to challenge board member Marian Greenblatt for the Republican Congressional nomination. Incumbents Joseph Barse and Carol Wallace, part of the conservative majority, are running for reelection. The primary is scheduled for Sept. 14.

Among the programs Klein said he would like to see improved are math and science classes and the use of computers on the secondary level.

"You may see a lot of candidates saying that they would like to see kids studying computer literacy in the elementary school, but my first priority is that we have good computer education, good vocational classes in the junior and senior high schools," said Klein, the father of four students, one in Churchill High School and three in schools that feed into it. "I don't really care if kids can play with computers in the fourth grade."

As for sex education, sure to be a hotly debated issue in the campaign, Klein said he supports the inclusion of information on contraception in sex education courses for high school students.

But on the most recent flap over a pilot program in eighth grade classes that included contraception information, Klein said he does not know whether he would vote to remove the program at that level. He has no problems with his own children viewing the material but thinks public hearings and a mailing to parents should be conducted before any future decisions.

Although Klein initially sought the endorsement of the avowedly liberal EDPAC (Education Political Action Committee) and did not receive it, he now says he will campagin against the four candidates endorsed by the committee.

Klein opposed the selection process, saying it should have been made after the primary and it has resulted in as much polarization among other candidates and the community as that caused by the current conservative majority.

On a lighter note, Klein said that if elected, his first resolution would be to prohibit any board vote after 11 p.m.