When Congress returns next month, it will be missing one of its most durable institutions: a big, gruff, faintly rumpled man who has personified organized labor on Capitol Hill for a quarter of a century.

Andrew J. (Andy) Biemiller's retirement as chief lobbyist for the AFL-CIO comes at a low point in union influence at both ends of Pennsylvania Avenue and will inevitably be viewed as a milestone in the passing of a era.

He came out of the political ferment of the 1920s and 1930s, a Sandusky, Ohio, bond salesman's son who went on to become a history professor, labor organizer, political operative for socialist Norman Thomas and two-term Democratic congressman from Wisconsin before making a career out of being George Meany's eyes, ears and voice on Capitol Hill.

Together these two aging figures-one 72 and retiring, the other 84 and hanging on-tell a lot about the labor movement and the evolution of its influence in Washington.

Biemiller, one of Meany's closest friends and most trusted lieutenants, is an apostle of the old school of labor lobbying, with its dependence on time-tested loyalties, lobbyist-to-lawmaker contacts and shoe-leather-and-telephone techniques.

Over the years, Biemiller came to be regarded as an impresario of this technique, probably the single most influential lobbyist in town.

But Congress has changed in many ways in recent years, responding less to institutional discipline AND TRADITIONAL LOBBYING EFFORTS THAN TO GRASSROOTS PRESSURE HELPED ALONG BY PUBLIC RELATIONS CAMPAIGNS AND COMPUTERS-OFTEN LEAVING LABOR CHOKING IN THE DUST OF ITS SPINS AND LURCHES.

YOUNGER MEMBERS COMPLAIN THAT THE MEANY-BIEMILLER OPERATION HAS LOST TOUCH, NOT ONLY WITH HOW LOBBYING IS DONE THESE DAYS BUT WITH VOTERS, INCLUDING YOUNGER UNION MEMBERS. EVEN SUCH LABOR STALWARTS AS HOUSE SPEAKER THOMAS P. (TIP) O'NEIL JR. (D-MASS.) HAVE ON OCCASION PUBLICLY CHIDED THE UNIONS' LOBBYING OPERATIONS.

OTHERS SAY THE PROBLEM IS NOT SO MUCH LOBBYING TECHNIQUES BUT THE WANING INFLUENCE OF UNIONS GENERALLY.

"A LOBBYIST CANNOT RISE ABOVE HIS PRINCIPAL." SAID JOSEPH L. RAUH, A LIBERAL WASHINGTON ATTORNEY WHO HAS BEEN BOTH ALLY AND CRITIC OF THE UNION MOVEMENT OVER THE YEARS. "ANDY BIEMILLER COULD HAVE BEEN A DEMOSTHENES AND STILL NOT HAVE MOVED CONGRESS FOR THINGS I LIKE SITUS PICKETING AND LABOR REFORM," TWO OF LABOR'S LOSING ISSUES OVER THE PAST TWO YEARS, SAID RAUH.

BUT TO DWELL ON THE CURRENT MALAISE IS TO IGNORE THE INFLUENCE-ECLIPSING THAT OF MOST LAWMAKERS-THAT BIEMILLER HAD ON A BROAD ARRAY OF SOCIAL LEGISLATION AND RELATED ISSUES OVER THE LAST FOUR DECADES. SOME CREDIT BIEMILLER AS A PRINCIPAL FORCE IN THE AFL-CIO's involvement in civil rights and health-care issues, for instance.

As a congressman, he was the late senator Hubert H. Humphrey's (D-Minn.) principal ally on the Democratic convention platform committee during the 1948 fight over a civil rights plank. Later, as a lobbyist, he joined with civil rights groups to buck opposition from the Kennedy administration and write a fair employment practices clause into the 1964 civil rights bill.

His fight for national health insurance was longer and less successfull. He started pushing the idea as a member of the Wisconsin legislature in 1937 and was still pushing it as Congress went home last October.

"I guess that's my biggest disappointment-the utter lack of anything on health insurance after Medicare," he said the other day, reminiscing with a reporter about his lobbying career.

But there were a few bright spots along the way. After winning election to Congres in 1944, losing in 1946, winning in 1948 and then losing again in 1950 and 1952, "the AMA [AMERICAN MEDICAL ASSOCIATION] FINALLY THOUGHT THEY HAD GOTTEN RID OF ME . . . THEY'D TRIED THEIR BEST, RUNNING THE DAMNEDEST AD YOU'VE EVER SEEN AGAINST ME WITH THE NAME OF PRACTICALLY EVERY DOCTOR IN MILWAUKEE ON IT . . . BUT THEY WEREN'T RID OF ME YET." IN THE 1960S, SPONSORS OF MEDICARE LEGISLATION WERE CONSIDERING THE "SLIMMEST LITTLE STUPID COMPROMISE YOU COULD IMAGINE" BUT CAME TO HIM, AS AFL-CIO lobbyist, and asked whether to hang tough. He said yes. "Then in the next election, bingo . . . Wilbur Mills [the former chairman of the House Ways and Means Committee] read the election returns and became a convert . . . We go a real bill."

On another ocassion, he slipped one past Mills, winning a public hearing for the first time on national health insurance by introducing a bill without any financing provisions, thus making an end run around Ways and Means. "He hated me for it," recalled Biemiller, "but he said, 'I take my hat off to you, you found a way to get a hearing.'"

If health insurance was the low point, the defeat of Supreme Court nominiees G. Harold Carswell and Clement F. Haynsworth during the Nixon administration were high points. Joining forces again with civil rights leaders, "we were bullheaded and just fought it out . . . even picked up some Wall Street lawyers along the way who didn't want them either," Biemiller recalled.

To Biemiller, bullheadedness has a place in lobbying if it means never giving up. "Sure it's frustrating sometimes," he said, "but we keep coming on back. This is the only reason the labor movement ever succeeds and why it will continue to succeed. We simply never take no for an answer."

Biemiller, who has been plagued by health problems that restricted his activity on the Hill in recent years, insists he isn't retiring in frustration but acknowledges that Congress is now more difficult for labor to deal with. "No one has ever been under the illusion that there's much discipline up there, but it was a lot better in the old days than it is now . . . Candidates run on their own and think about their own districts, their own reelection."

At one point, he noted, there used to be "175 to 190 guys up there you knew were going to vote right." Now it's down to 140 or 145, "the rock-bottom people you can count on when the chips are down.Oh I've gotten all kinds of lovely notes here from people telling me how they love me . . . But all the never guys are concerned about is getting reelected."

To get some of these newer people, the AFL-CIO used more grass-roots lobbying techniques last year on the labor law revision bill but still fell short. Biemiller went along with the new practices but not without misgivings, colleagues said.

With a "conservative trend" in last fall's voting, the proliferation of single-issue lobbies and the increasing sophistication of corporate lobbyists, Biemiller predicted next year will be even tougher for his former deputy and successor, Kenneth Young.

Young, 51, who's been an AFL-CIO lobbyist since 1967, is a "worthy successor," said a business lobbyist who admires Biemiller but belives he "stayed on a few years to long."

Biemiller came into the labor movement by way of the LaFolletes and Norman Thomas for whom he politicked on the fringes of the Bonus Army encampment here in 1932. Earlier, as a teen-ager, he did his bit for one of the LaFollettes by papering a postoffice in Sandusky with LaFollette literature, bedeviling a Republican postmaster.

He was recruited to Milwaukee by the socialist mayor at the time, Daniel Webster Hoan, who had gotten to know Biemiller during the 1932 Thomas campaign. He joined the labor movement there and ran for the state legislature, serving as floor leader for LaFollette's Progressives. He worked as labor specialist for the War Production Board in the early 1940s, quitting in 1944 to begin his revolving-door career in Congress, where he became a pupil of Speaker Sam Rayburn (D-Tex) in parliamentary tactics-a discipline he later put to good use.

After Biemiller lost in his final bid for Congress of President Truman, who wanted his expertise in fighting the AMA, Meany asked him to join the federation's legislative staff. "He said, 'Come back where you belong,' and I did," Biemiller recalled. It was, he added, a decision he would never regret.