Lawyers for Marvin Mandel pinned the former Maryland govenor's legal hopes yesterday on two new federal judges -- an up-from-the-bottom West Virginian who twice ran for govenor there and a lawyer fresh from one of Baltimore's establishment firms.

In a formal petition, Mandel's attorney asked a federal appeals court in Richmond to hear the case yet again, but this time with two new judges on the bench. That court, in a 3-o-3 decision July 20, had reinstated the mail fraud and racketering convictions of Mandel and his five codefendants.

The court's deadlock "has served the interests of no one," the lawyers argued in their petition to the 4th U.S. Circuit Court of Appeals.

When a case "can be decided through the participation of newly appointed judges, the equal division is intolerable, and there is no choice but to grant a rehearing," they said.

Since the July 20 ruling, Francis D. Murnaghan Jr., a 59-year-old lawyer from one of Baltimore's most powerful law firms, has joined the 4th Circuit.

James M. Sprouse, a Charleston, W.Va., lawyer who came within 12,000 votes of becoming West Virginia's govenor is 1967, has been nominated to the court and is awaiting Senate confirmation.

Murnaghan's participation in considering the Mandel case, however, could be in doubt.

During Mandel's administration, Murnaghan served at least once as special counsel for the state in a major lawsuit. Mandel's former aides also recall Murnaghan meeting with the govenor in Annapolis a few times on various civic matters.

Asked whether he would have to disqualify himself from hearing the case for these reasons, Murnaghan meeting acknowledged yesterday that it is a question he'd "have to resove." But he refused to discuss the case further.

Judge Harrison L. Winter, a 4th Circuit member also from Baltimore, previously disqualified himself from hearing the matter.

But Mandel's lawyers appeared to be urging both men to consider this latest appeal when they argued in their petition "that a judge should hsitate to disqualify himself if his participation will assist in resolving an equally divided court."

The lawyers also apparently are banking on the court waiting to take action until Sprouse's nomination has been confirmed, probably in mid-September.

Sprouse, 55, rose from a humble background in West Virginia coal region to attain a seat on the state's highest court, where he was known as a liberal jurist. He left that position to run in the state's Democratic gubernatorial primary in 1976, where he was beaten by now-Gov. Jay Rockefeller.

Murnaghan, considered an expert in libel law, was for years one of the lawyers for the powerful Baltimore Sunpapers. Though he has never run for public office himself, he has been a top fund raiser and leader in the campaigns of Sen. Paul Sarbanes (D-Md) since 1966.

If Mandel and his codefendants fail in their bid for a 4th Circuit rehearing, they may still appearl to the Supreme Court.

The case, which began with Mandel's indictment in 1975, already has included mistrial, a conviction, a reversal by an appellate panel and finally last month, the split-vote conviction reinstatement.