When Secretary of State George P. Shultz met with a group of skeptical conservative senators March 5 to reassure them that U.S. military aid was finally flowing to anticommunist guerrilla forces in Angola, he was repeatedly told bluntly by Sen. Jesse Helms (R-N.C.), "You got to fire Crocker! You got to fire Crocker! The African bureau is not carrying out administration policy."

Among foreign policy specialists dealing with Africa, one of the most often-asked questions these days is when Chester A. Crocker, the embattled assistant secretary of state for African affairs, is going to return to the academic world whence he ventured into the wilds of Washington politics five years ago.

Crocker's comments Wednesday before a House committee that the administration favors black-majority rule in South Africa and at least "in the generic sense" regards the Soviet-backed militant nationalists there as "freedom fighters" is likely to add new fuel to a conservative-led drive to get him fired.

Already, rumors are flying fast and furious around Washington that Crocker, who holds the record for longevity among the State Department's assistant secretaries, will soon depart -- some say this spring or early summer.

Similar rumors promoted mainly by his conservative critics late last fall, however, proved erroneous. Moreover, a new glimmer of hope for a breakthrough in the long-deadlocked southern Africa talks he has personally conducted since 1981 make an imminent departure questionable, according to several State Department officials.

Crocker, always reticent, is not talking. Repeated telephone calls to his office over a three-day period to confirm or deny the rumors were unavailing.

For many conservatives and liberals alike, Crocker, as chief architect of the administration's much-maligned "constructive engagement" policy, has overstayed his welcome by many months. One associate described him recently as "a man with enemies on all sides."

Liberals believe he has been thoroughly duped by South Africa's white rulers into promoting a policy that counts on quiet diplomacy and carrots rather than sticks to wheedle reform out of the Botha government. They have indicted him for seeking to block the grass-roots swell last fall of public demand for the imposition of U.S. economic sanctions on South Africa.

Crocker still prefers the terms "political sanctions" rather than "economic sanctions" in describing the measures that President Reagan, under pressure, finally agreed to impose. Among other things, the sanctions ended the sale of hundreds of millions of dollars worth of South African gold krugerrands in the United States.

Conservatives, on the other hand, have denounced Crocker in their publications for opposing the "Reagan Doctrine," the administration's efforts to help anticommunist "freedom fighters" in their battles with Soviet-backed Marxist regimes in the Third World.

They charge that Crocker has almost singlehandedly been responsible for the administration's months of delay in sending any U.S. military aid to the anticommunist forces of Jonas Savimbi in Angola.

Caught in the midst of these sea changes in U.S. foreign policy, under attack from both left and right, Crocker has remained as unflappable as an accomplished, life-long diplomat -- which he is not. His background is entirely as an academic specialist in African affairs; before joining the administration, he was head of the African Studies Program at Georgetown University's Center for Strategic and International Studies. Yet to the chagrin of his detractors, he has proven an extraordinarily good bureaucratic infighter. And he is a master of the linguistic ambiguity that is the trademark of his temporary profession.

His double-edged or round-about replies to questions have been known to drive congressmen and reporters to despair, leaving nagging doubts about whether he really said "yes" or "no" to a delicate question.

One example was a session with State Department reporters Jan. 28, where he was questioned about shifting U.S. policy toward Angola. Crocker, feeling the heat from conservatives, said for the first time that U.S. firms doing business with the Marxist Angolan government ought to "think about U.S. national interests."

Reporters, sensing an important new direction in administration policy, sought clarification as to whether he was saying they should get out. Try as they might, they could get no straight answer.

What should American companies "think about," staying or getting out of Angola, several reporters asked.

"What should they do? They should think. They should also communicate, make clear what the sentiments are like in Washington," replied Crocker.

"Does the presence of those American companies in Angola further or inhibit the process of developing a peace settlement" in southern Africa, asked one reporter. "Well, we wonder sometimes," replied Crocker.

"What do you conclude when you wonder?" the reporter persisted.

"At the present moment, we need all the signals we can send for people to get on with it. Thank you," Crocker said, winding up the news conference and leaving behind a roomful of thoroughly bewildered reporters.

Crocker has shrouded his real feelings for U.S. covert military assistance to Savimbi in the same diplomatic ambiguity. His stock answer these days is that he supports "effective and appropriate" aid for Savimbi's forces.

But whether this includes military assistance or just a redoubling of U.S. efforts to get a political settlement that would obviate any need for a direct American involvement in Savimbi's cause always remains unclear -- to the enormous irritation of his conservative critics.

In the past, Crocker has resisted any such direct U.S. entanglement in the Angolan civil war, fearing this would undermine his already slim chances for getting a negotiated settlement between Angola and South Africa. The linked issues at stake for him are independence for South African-administerted Namibia and the withdrawal of 35,000 Cuban troops from Angola.

He has also opposed, according to those close to him, adding the prickly problem of national reconciliation between Savimbi and the Marxist Angolan government to the already overcharged agenda he carries with him on his on-again, off-again shuttle diplomacy between Pretoria and Luanda over the past five years.

In what is probably the twilight of his stay in office, Crocker still has some friends with a good word for him. I. William Zartman, director of the African studies program at Johns Hopkins School of Advanced International Studies, gives Crocker high marks for doing his best to get two enemy nations, South Africa and Angola, to talk peace.

"If there's a fault it's up at the lofty summit of the administration, which didn't come in behind him," Zartman said.