The jury in the political corruption trial of Maryland Gov. Marvin Mandel concluded its fourth day of deliberations today without reaching a verdict, dashing the expectations of many attorneys who thought a decision was imminent.

The letdown came this evening, eight hours after the day began with the hopeful news that ailing juror Theodore T. Brown had been released from Mercy Hospital and had rejoined his colleagues. Deliberations thus were able to be resume after being postponed for a day while Brown was hospitalized.

On Friday night, just before they finished their third-day of deliberations, the jurors had asked for extra verdict forms - a request that many attorneys interpreted as a sign that the panel was ready for a final vote.

"It's puzzling," said William G. Hundley, attorney for Mandel code-fendant W. Dales Hess. "They haven't asked a single substantive question" since they went behind closed doors Wednesday morning.

"You can usually tell what is hanging (most jurors) up by the requests they make," he added. "But (the Mandel jurors) are not communication their problems."

Hundley and other attorneys speculated today that the awesome nature of the panel's task is probably the basic reason for the lengthy duration of the deliberations, which have now taken 40 hours. The jurors must make 129 separate determinations of guilt or innocence involving Mandel and five codefendants.

Manuel attorney Arnold M. Welner interpreted the panel's decision to stop deliberating earlier than usual today as a sign of "serious division over issues of substance." Normally the jurors end their work between 7:30 and 9 p.m.

Juror Brown was released from Mercy Hospital about 8:30 a.m. today after spending two nights under observation. He collapsed Friday night, suffering from what was apparently a reaction to penicillin.

Mandel, Hess, brothers William A. and Harry W. Rodgers III, Irvin Kovens and Ernest N. Cory Jr., all are awaiting the verdict on their charges of 20 counts of mail fraud and three counts of violating federal anti-racketeering statutes in an alleged scheme to defraud the citizens of Maryland.

The day began as a nervous procession of attorneys walked past a knot of journalists into the vast courtroom lobby after hearing that the jury had resumed deliberations. For most of the morning they paced and they joked and they paced again.

The expectation of a verdict was so great that many people ordered their lunch brought in, forgoing the usual leisurely midday meals.

But as the afternoon melted away, the attorneys and the journalists sagged into the red lounge seats. Dashed vacation plans overcame verdict predictions as the topic of the moment.

Christopher Holy, a 26-year-old attorney who has served as Weiner's assistant throughout the trial, began worrying today that if the deliberations dragged on too long, he might have to postpone his wedding for a fourth time. All three earlier postponements were made because of the Mandel case.

"First it was going to be February, then March, then - when was the first trial going to begin? - oh, yeah, it was going to be last June. Now it's Sept. 11, and I hope we make it," Holy said.

This is the second trial of Mandel and his five codefendants, who were indicted almost two years ago.The first trial, which lasted 13 weeks, was aborted last Dec. 7 when the presiding judge declared a mistrial. Some of those jurors inadvertently heard news accounts of attempts to tamper with the jury.

To avoid another mistrial, federal marshals here have taken extraordinary precautions to isolate the jurors.

This morning, when Brown was released from Mercy Hospital, the marshals apparently devised a ploy to insure that the juror did not come into contact with reporters.

A Baltimore photographer who was at the hospital said that federal mashals escorted a man whom they addressed as "Mr. Brown" to a waiting car with taped windows outside the hospital's emergency parking lot.

But just as that "Mr. Brown" got into his car, a second unmarked vehicle, carrying the real juror, sped away from the freight loading hospital entrance the wrong way up busy Calvert Street, the photographer said.