The AFL-CIO Executive Council today voted to move its presidential endorsement forward from mid-December to the first week in October, which is universally regarded as a high-voltage boost for the candidacy of Walter F. Mondale.

Beyond the extra 60 days this gives the labor federation to gear up its refurbished political machinery, the decision marked the inability of two of Mondale's major rivals for the Democratic presidential nomination, Sens. John Glenn (D-Ohio) and Alan Cranston (D-Calif), to prevent the speedup.

Cranston and Glenn argued that the original December endorsement date gave them more time to present their cases and try to offset Mondale's advantage as a long-time friend of labor.

The labor chiefs, however, clearly felt that delaying until early October, the time of the AFL-CIO national convention in Florida, was the maximum they could afford in payment of their debt to Cranston, who contended that his record as a friend of labor is comparable to Mondale's.

The labor leaders, determined to end what they see as more than a decade of impotence and frustration in presidential politics, shrugged off warnings about the risks inherent in AFL-CIO President Lane Kirkland's pre-primary endorsement strategy.

"There is only one risk that concerns me," said Kirkland, announcing the council's 23-to-6 decision. "That is the great risk of doing nothing and letting other people run your life."

The move to make the endorsement at the federation's convention, which will be attended by more than 3,000 delegates, means "the question will have been put to everybody within the trade union movement," Kirkland said. He emphasized that the federation leadership had tried to keep the process open and in tune with rank-and-file sentiment.

Council members described the objections of the six who voted against the decision as mild, based on the technical grounds that the speedup would cause their unions logistical problems or their sense of obligation to Cranston.

"I think Mondale's got it. I think Mondale always had it," said Douglas Fraser, the retired president of the United Auto Workers, who still is a council member. "In all the discussions I've only heard one guy make a strong case for anybody else a Glenn backer . The six votes today were partially out of deference for Alan."

Cranston today called the AFL-CIO decision "a boost to Walter Mondale's campaign," and added, "While I personally feel that the endorsement date should not have been moved up I respect those leaders who felt differently and I believe they have the right to make that decision."

Both the Glenn and Cranston camps indicated that they would not retaliate by running an anti-labor campaign and trying to play to those who believe that labor's endorsement could be detrimental because many distrust it as a special interest.

"Cranston is too good a friend of labor to walk into any state and not pay the courtesy calls," and generally maintain his good relations, said Victor Kamber, a Cranston aide. "Hurt he may be. Upset he may be. But disenchanted with the labor movement. That would be stupid and ludicrous."

William White, campaign manager for Glenn, said after the decision that Glenn will not attack Mondale as a captive of the labor bosses.

"We are certainly not going to make an issue of bossism," he said. "Organized labor has the absolute right to express its political position."

Glenn aides expressed envy and admiration at the arsenal of high-tech and shoe-leather political resources they assume labor will soon deliver to their opponent.

"If they are able to do half of what they're describing it will be brilliant and overwhelming," said one, describing the sophisticated automated data base, phone banks, armies of trained volunteers and other resources being marshaled by the AFL-CIO's political arm. "As a political technician, it makes my mouth water."

This machinery will be unleashed on behalf of the chosen candidate, presumably Mondale, before the first primary and caucuses next year, in contrast to the AFL-CIO tradition of waiting until a party nominee has been chosen.

"We think it is in the best shape it's been in since the early 1960s," Mondale aide Paul Jensen said of labor's political apparatus.

The endorsement means that this political machinery will get full play nationwide even if some elements such as affiliate unions, locals or individuals choose to work for a candidate other than the one endorsed by the federation.

The labor leaders seemed unswayed by any indications that the political winds have blown in Glenn's direction this summer. That perception is based partly on recent polls and arguments that Glenn has less negative political baggage than Mondale and a more broadly based appeal to the electorate.

Kirkland maintained that the fortunes of the various candidates were irrelevant to the council's decision.

By all accounts, Mondale started out way ahead with the labor leaders 18 months ago and never let up the pressure in the form of phone calls and personal contacts. As early as June, his allies on the council started campaigning to move up the endorsement.

In a world where personal loyalties are highly valued, many labor activists said they have felt only an arm's length personal relationship with Glenn and that they found his positions on issues dear to unionists lacking.

There also is skepticism about how well Glenn will stand up to the pressure and scrutiny of a presidential race, which he has so far largely avoided, one labor official said.

"Mondale, by contrast, appears to be relaxed, at peace with himself, a guy who knows what he wants to say and how to say it, a guy past the point where he is being tugged in all different directions by different advisers."

In other activity, the presidents of seven Boston-area locals, including service workers and steel workers, called for Kirkland to resign from President Reagan's Commission on Central American Policy, which is headed by Henry A. Kissinger. The group is protesting Reagan's "interventionist" policies in El Salvador.