A federal judge has accused Supreme Court nominee Robert H. Bork of improperly attempting to substitute his own views for the reasoning agreed on by the two other judges hearing a controversial 1983 case -- actions that "reflect serious flaws in his character."

In a five-page letter to the Senate Judiciary Committee, retired U.S. District Court judge James F. Gordon of Kentucky said Bork's conduct as a judge on the U.S. Court of Appeals here called into question his "basic honesty."

Gordon, who was appointed to the federal bench in 1965 by President Lyndon B. Johnson and who said he was often described as a "crusty old conservative," wrote the committee Aug. 24 that he felt "duty bound" to inform it of Bork's alleged actions when Bork was assigned to write the majority opinion in a challenge by House Republicans to committee assignments under the Democratic majority.

Gordon, sitting in as one of three judges who heard the case, said he and the late Judge Roger Robb and Bork all agreed that the case should be dismissed on the narrow grounds that the court should not interfere in the case. Gordon said he and Robb "took immediate vigorous exception" to Bork's suggestion that the case should be decided on the alternate grounds that the members of Congress lacked standing to sue.

Gordon said he was "shocked, to say the least" several months later when -- without explanation -- he received Bork's draft majority opinion, which decided that there was no standing for the legislators to sue. "There is no way Judge Bork could have misunderstood Robb's and my position."

Gordon said he called Robb's chambers to see if Robb had changed his mind and discovered that Robb had been hospitalized with cancer. Gordon said he received instructions from an unnamed judge on the appeals court who said Robb was "upset by developments" and that Gordon should write the opinion on the previously agreed upon grounds. Bork eventually filed a concurring opinion.

Gordon said he had "grave reason to suspect that perhaps Judge Bork intended to have his narrow 'no standing' view become the majority opinion of the court and the law of the circuit when, in fact, it was the minority opinion."

" . . . I do not believe one who would resort to the actions toward his own colleagues and the majesty of the law as did Judge Bork in this instance," Gordon wrote, "possesses those qualities of character, forthrightness and truthfulness necessary for those who would grace our highest court."

Bork declined to comment but released a letter he said he sent Gordon at the time. "It occurs to me too late that I should have notified you in advance that I had changed the rationale . . .to one of lack of standing," the letter said.

Gordon said yesterday he did not receive the letter.

Bork's clerk in the case, Paul J. Larkin, now an attorney in the solicitor general's office, said he recalled that Bork, shortly after the three judges met, went to see Robb and discussed the case.

"I remember when he {Bork} came back" and said Robb had agreed to change the focus of the opinion, Larkin said. "There was no effort to attempt to pull a fast one," he said, adding that such a ploy could never succeed because Robb would have seen the opinion before it became final, as would all the judges on the circuit.

Larkin said Gordon's accusations were "all a misunderstanding" since Gordon, who sat on a court in Owensboro, Ky., was not present for the later discussions. Another source familiar with the situation said that Bork may have misunderstood Robb's position or may have changed his mind later.

Gordon yesterday defended his recollection of the proceedings. "All I know is that Robb signed the opinion I wrote," he said, and that opinion reflected what they had discussed in conference.

Judiciary Committee Chairman Joseph R. Biden Jr. (D-Del.) last week sent a copy of Gordon's letter to the American Bar Association's Standing Committee on the Federal Judiciary. The ABA committee met yesterday to consider Bork's qualifications, although it was not known last night whether the committee investigated Gordon's complaint.