Democrats on the Senate Judiciary Committee mounted a stinging attack yesterday on William Bradford Reynolds' nomination to the No. 3 job at the Justice Department, with Sen. Howard M. Metzenbaum (D-Ohio) charging that Reynolds has often "come down . . . on the side of the bigots."

Several Democrats described Reynolds as a zealot who has used his position as assistant attorney general for civil rights to twist the law in an effort to decimate federal civil rights enforcement.

But the panel's Republican majority generally endorsed Reynolds' record during the first day of confirmation hearings on his nomination as associate attorney general. Sen. Jeremiah Denton (R-Ala.) accused critics of trying to "subject Mr. Reynolds to a civil rights litmus test based on . . . racial goals and quotas."

The hearing quickly became a forum on the Reagan administration's attempt to move away from school busing, hiring quotas and sweeping lawsuits in favor of narrower remedies for discrimination against minorities, women and the handicapped.

"In my view, Mr. Reynolds has done enough damage to civil rights at his current level in the Department of Justice and he does not deserve to be promoted," Sen. Edward M. Kennedy (D-Mass.) said. Sen. Paul Simon (D-Ill.) said Reynolds frequently misinterpreted the law to support his "skewed vision of civil rights."

The Democrats' criticism was not uniform, however. "I happen to agree with you on busing," Sen. Joseph R. Biden Jr. (D-Del.) told Reynolds. "I happen to agree with your view on quotas." But he said Reynolds believes "that the entire civil rights agenda has been promoted too much by this country."

Republicans on the committee stood by the nominee. "You've been sincerely enforcing the civil rights laws as you see them in the best possible way you possibly can," Sen. Orrin G. Hatch (R-Utah) said.

Reynolds, normally a combative witness, responded calmly and methodically to the sharpest criticism. He said he has "vigorously enforced" the civil rights laws and in some areas has filed more cases than previous administrations had. He said he was not trying to "pick fights" with local officials, but strongly defended his effort to eliminate quotas from more than 50 affirmative-action hiring agreements approved by the courts.

The Democrats focused their fire on two cases in which Reynolds overruled his staff's recommendation that he bring action under the Voting Rights Act. In one case, Reynolds approved the shift of a Selma, Ala., polling place from the heart of a black neighborhood to a courthouse in a nearby white area.

Metzenbaum read a memo in which Reynolds' staff blamed the move for a "significant decrease" in black voter turnout, from 54 percent in 1980 to 36 percent last year. Reynolds approved the polling shift earlier this year, saying any link to lower black voter turnout was a "fanciful conclusion."

"I think that is shameful on your part," Metzenbaum said. "I'm embarrassed for you . . . .

"You're intelligent. You appear to be a decent human being. And yet you've come down in some of these cases on the side of the bigots," Metzenbaum said.

Biden challenged Reynolds' approval of a Louisiana redistricting plan that ruled out a majority-black congressional district in New Orleans. A federal appeals court later struck down the plan.

Biden said Louisiana's then-Republican governor vetoed an earlier plan that would have created the majority-black district, and that state officials excluded blacks from negotiations over the revised plan. Biden said Reynolds' staff had told him of allegations that a key state legislator had said that "we already have a nigger mayor and we don't need another nigger big shot."

Reynolds said he concluded that the redistricting was based on politics, not race. Biden called that explanation "suspect."

At another point, Kennedy challenged Reynolds' role in the administration's 1981 effort to preserve a tax exemption for segregated Bob Jones University. "How could you possibly justify granting tax benefits to racist schools?" Kennedy asked.

"Senator, I can't justify that. I'm opposed to that," Reynolds said. He said he had argued only that the Internal Revenue Service did not have the legal authority to withdraw the tax breaks.