Some of the glitter of Republican campaign promises began to fade und the harsh glare of budget realities yesterday as President-elect Ronald Reagan's Cabinet nominees started their confirmation parade on Capitol Hill.

Setting the tone for what may be major fine-tuning of the Reagan legislative program, Treasury Secretary-designate Donald T. Regan told the Senate Finance Committee that the incoming administration no longer anticipates a balanced budget before its fourth year in office. This is two years later then Reagan had wanted -- and a year later than he had promised -- for an end to budget deficits.

At the same time, Casper W. Weinberger, Reagan's choice for secretary of defense, resisted committing the administration to a fixed annual percentage increase in the Pentagon budget. "I don't believe in fixed percentages," Weinberger told the Armed Services Committee in an echo of Carter administration reluctance to be locked into specific percentage increases, adding that the real question is whether the country is "getting the strength we need."

On the domestic side, Richard S. Schweiker, whom Reagan has tapped to head the Department of Health and Human Services, told the Finance Committee that it may require a slow down in benefit growth or delayed retirement of older workers to keep the Social Security system from bankruptcy.

John R. Block, the secretary-designate of agriculture, told the Agriculutural Committee that he would be "very reluctant" to impose an embargo on food shipments to foreign countries as a foreign policy weapon.

In the new administration's first public pronouncement of Japanese auto imports, Commerce Secretary-designate Malcolm Baldrige told the Commerce Committee that he favors talks with Japan to resolve the trade conflict with the two countries.