The longtime head of the huge labor federation was in failing health absent for weeks at a time from his office, but reluctant to drop the reins. For the man who would eventually pick up those reins, a vigorous young George Meany, it was a trying time.

That was nearly 30 years ago, in the waning days of William Green's stewardship of the old American Federation of Labor. Now Meany, aged 84 and physically ailing, has been absent from his office since early April, leaving the day-to-day operations of the AFL-CIO to trusted lieutenants and guiding policy by remote control from his home in suburban Maryland.

In part because Meany, mindful of the Green example, has repeatedly said he would retire as soon as he left too old or ill to lead, many close associates expect him to step down in time for the AFL-CIO convention to elect a successor when it meets in November.

But no one claims that Meany has confided his intentions, or even inclinations, to anyone. "Only he knows, and I'm not even sure he knows yet," one close confidant said.

Another suggested that Meany's command over the 14-million-member federation is so thorough that he could defer a decision until the third day of the convention, the normal time for his ritual reelection, and still win another term by acclamation.

Others are not so sure. If he doesn't make a decision soon, another insider said, "the wolves will come," inviting a messy change of command.

According to sources both inside and outside the federationn, Meany7s absence has had no discernible impact on day-to-day operations of the AFL-CIO, which, as one observer put it, are "functioning smoothly on automatic pilot." They were already in a kind of holding pattern in anticipation of an ever-imminent transfer of power to Secretary-Treasurer Lane Kirkland, Meany's heir-apparent.

"Nothing new and especially creative is getting started," said one longtime AFL-CIO watcher, "but then it wasn't happening before he went to the hospital, either."

The protracted uncertainty is spawning wave upon wave of speculation, however, not only about the state of Meany's health but about successors.Among other things, there is talk of a "building trades" candidate, such as Plumbers President Martin Ward or Operating Engineers President J.C. Turner, neither of whom is actively running. Prospects for an easy succession by Kirkland, who came out of the Merchant Marine union, appear strong now, but some say they may diminish as time goes by.

It had been expected that Meany, who alway declared his reelection intentions well in advance of the federation's biennial conventions, would do so this time at the midsummer meeting of the AFL-CIO Executive Council in Chicago Aug. 6-8. For weeks, it had also been expected that he would be back in his office "in 10 days," a prophecy renewed with each flip of the calendar.

But he has still not returned, and aides said yesterday he will not attend the Chicago meeting and is unlikely to communicate his intentions at that time. Some union officials are now looking to his birthday party, planned for September in New York, for the word.

While Meany has not been seen in public since before his hospitalization in late April, friends who have seen him report that he is as mentally acute as ever and eager to return to work.

Unlike Green, they point out, Meany is beset only with physical problems, and has bounced back before confounding 10 years or more of premature retirement notices. But other note, he was not then just a month away from his 85th birthday.

Meany, who was hospitalized briefly earlier in the year for a recurrent bronchial ailment, injured his knee in a golf cart in April and was hospitalized again shortly thereafter.

The knee injury complicated a longstanding hip ailment, immobilizing and weakening him. He has reportedly lost more than 20 pounds and look frail. Even his voice has lost some of its familiar booming quality. He is unndergoing therapy twice a day, but exercising is highly painful and tempting to avoid, aides say. His spirits are said to rise and fall, but to be generally good.

The operating Engineers' Turner visited Meany recently and found him "very vigorous and quite optimistic in his outlook." Turner, in contrast to a number of his colleagues, says he expects that Meany will seek another two-year term. CAPTION: Picture, George Meany: Ailing labor chief is reported "virgorous and quite optimistic.", AP