It was late afternoon in the office of Sen. Lowell P. Weicker Jr., and the fate of the Labor Department Women's Bureau was hanging by a thread.

The Connecticut Republican was closeted with nine staff members from his Senate Appropriations subcommittee for a line-by-line review of the three departmental budgets he oversees. He stopped abruptly at Line 9450, questioning the staff's recommendation that the Women's Bureau receive $5 million.

Subcommittee staffer Jim Sourwine defended the program as important to women, but acknowledged that the bureau spends 80 percent of its money on personnel and 20 percent on grants.

Turning to the three women in the room, Weicker asked: "Why is this such a great deal as far as women are concerned? Four million dollars for bureaucrats and one million to help people? Have we zeroed in on this thing at all?"

The aides replied that they would call on former subcommittee staff director Claudia Ingram -- who married Weicker last year -- to make the bureau's case at home.

The July 30 session was not listed on the congressional calendar, and no other senators were invited. It was simply a chance for Weicker to devise his recommendations for the fiscal 1986 budget, which his subcommittee is due to vote on today.

Since Weicker has a GOP majority on the subcommittee and is in tune with his Democratic counterparts in the House, his recommendations should be very close to the budget Congress finally adopts for the departments of Labor, Education, and Health and Human Services. And few are likely to challenge him if he decides to delete an item like the Women's Bureau -- which he later agreed to retain.

Those who envision Weicker as a free-spending liberal might have been surprised at the July staff sessions, which he allowed a reporter to attend. Leaning back in his leather chair, felt-tip pen in hand, the burly chairman sliced up several small social programs, saying they were a waste of money.

Staff director John Doyle and his aides framed the terms of the debate, outlining areas to be trimmed or fattened. They frequently had to act as advocates for certain programs, relaying the arguments of agency officials they deal with daily.

But Weicker never relinquished the power to dictate each line item. The aides -- who call him "senator," even in private -- lost several arguments for more funding.

How Weicker arrived at a $33.4 billion budget for discretionary programs at the three departments tells a great deal about the collapse of Congress' deficit-reduction drive. Weicker decided in July to seek $4 billion more for those programs than President Reagan wants to spend. The original Senate budget resolution was more generous, but Weicker was still prepared to breach it by more than $1 billion.

By the time the Senate watered down its budget resolution in a compromise with the House, however, Weicker was able to restore hundreds of millions of dollars for programs such as the Job Corps and still come in just under the ceiling. Still, his "victory" simply means holding the line on most programs, not increasing them.

Weicker's staff disposed of some key decisions in a couple of minutes. But the senator spent nearly half an hour questioning why the budget for the National Institutes of Health's Library of Medicine should be boosted by $4 million to $59 million.

When health aide Steven Bongard explained that some of the increase would help upgrade a computerized reference system for doctors, Weicker demanded to know why something so important hadn't been done already.

"If they want $10 million, if they want $15 million, I'll give it to you," Weicker said, but he wanted assurances that such a system was within reach. Weicker agreed to the increase after his staff visited the library and reported it was making great progress on the computer system.

Politics was not in the forefront of the discussions, but it was never far from view. It popped up when the staff endorsed Reagan's proposal to freeze overhead payments on NIH grants to universities, saying these costs have soared out of control in recent years. A freeze would save $30 million.

"It's a hot political topic," Doyle warned. "You'll catch hell from the universities about that."

"When NIH tried to cut indirect costs, all the college presidents came out of the walls," Bongard said. "You will get some phone calls, I promise you that." Weicker agreed to the freeze anyway.

Weicker also agreed to the administration's request for an extra $8.7 million for research on acquired immune deficiency syndrome (AIDS). But the staff complained that the administration was playing politics by making the request days after it was too late to be included in this year's supplemental appropriation.

Even Weicker couldn't suppress an occasional yawn as the sessions wore on, but the staff members were adroit at arousing his attention. Few neglected to say how some program or other would help the handicapped, a favorite Weicker cause.

Thus Doyle knew he needed ammunition when he confronted the President's Committee on Employment of the Handicapped.

"It's a joke," Doyle said. "Every spring, all the disability groups get to write off a trip to Washington, and as far as I can determine it does little else. It's one of those small little things that frankly makes a mockery of the federal government's involvement in human services."

But Weicker complained that "everyone will say we're against the handicapped" if he eliminated the panel's $2 million budget. He decided to cut it in half instead.

(Larry Volin of the president's committee said in an interview that the panel publishes brochures, briefs community groups and runs a computerized network for employers. "We don't get involved in placement or training, so it's hard to say how effective it is," he said. "Our mission is to educate and encourage . . . . We've sparked a lot of ideas.")

Weicker was also unmoved when the staff warned that many state unemployment insurance offices -- including those in the Connecticut capital -- might lose substantial funding because the jobless rate has been dropping. He rejected a $20 million boost for the offices.

The chairman threw his staff another curve when he refused to join their attack on a $10 million discretionary fund controlled by Education Secretary William J. Bennett. Riki Sheehan, Weicker's education aide, said Bennett has been using some of the grants to fund experiments with tuition tax credits and tuition vouchers. "It looks like a back-door way of promoting something he couldn't get legislatively," she said.

But Weicker, who opposes both programs, wasn't biting. "He's the new secretary," Weicker said. "If he wants to go ahead and throw some projects out there . . . I don't want him complaining that he hasn't been given the opportunity to develop his ideas."

Sheehan fared better with other cuts she proposed, such as eliminating $5 million in grants to promote "excellence in education," a brainchild of Sen. John Heinz (R-Pa.). "I think it's an expendable program," she said. "It sounds awfully duplicative. I think this might be one to go by the wayside." It was dropped.

But such surgical nicks were more than offset by big outlays such as Pell grants for college students. Weicker had won an increase for the aid program in this year's supplemental appropriation; to keep the same level for fiscal 1986, he would have to raise the funding from $2.6 billion to $3.5 billion.

"We could play the game of cutting it back now and coming back with the supplemental next year," Sheehan said. Weicker decided to go for the full increase up front.

In the end, what sent the greatest chills through the office was an obscure Education Department program called "independent living."

The administration was requesting money to set up "living centers" to help the elderly blind. But the assembled appropriators have seen towering social programs spring forth from such tiny acorns.

"This is a classic example of the Disease-of-the-Month Club," Doyle said. "If we can have independent living for the older blind, we can have it for younger cerebral palsy victims, for a guy with a bum leg who's 22 . . . . "

"Once you start this, we'll have a little NIH going," Weicker agreed.

"It's going to be hard to shut this baby down," added aide Jane West.

They finally gave the program $5 million, but no one pretended that would be the end of it.

"When the American Council for the Blind gets a few centers, they're going to want a few more centers," Doyle said, "and we're going to have their lips firmly affixed to the federal trough."