As C.W. Johnson lay dying of AIDS in Prince George's General Hospital, he told his niece that he had but one request: to take a bus back home to Florence, S.C., and see his mother.

But Johnson, 49, a proud man with a fourth-grade education who had worked his way from dishwasher to head cook at a Connecticut Avenue restaurant in his 30 years in Washington, never had enough money to make the trip because the government bungled his request for Social Security disability payments.

He waited 25 months after applying before his first check for $747 arrived. When the remaining thousands of dollars that the government owed him finally arrived last May at his house on 10th Street NE, Johnson was not there. He was being buried in South Carolina.

"When I got the check, I was so mad I wanted to tear it up and send it back and say, 'It's a bit late,' " said Mary Johnson of Gaithersburg, who cared for her uncle in his final years.

Yesterday, Social Security Commissioner Gwendolyn S. King said she was so troubled by the Johnson case that she was ordering new, clearer instructions be sent to her agency's 1,300 officies, spelling out how workers should expedite any disability claims filed by terminally ill applicants.

"This is one of those nightmarish situations where if something could go wrong, it did," King said. "This should never happen again."

Typically, officials say Social Security can make disability payments to qualified applicants within 30 to 60 days. But the officials said yesterday that they could not offer a precise explanation of what went wrong in the case of Johnson, who was owed $9,565.36 in disability back payments at the time of his death.

"It was just a series of mistakes," said Deputy Social Security Commissioner Lou Enoff. Letters and files apparently were lost and misdirected to Social Security offices across the country, he said.

Mary Johnson, who would travel daily from her McLean job to Prince George's General Hospital to be with her uncle, said he did not want to apply for any government assistance in the first place because he believed the disability program was established for "those who need it." He had been unable to work for nearly a year when, in February 1988, he finally sought help under the two Social Security programs that provide benefits to an estimated 30,000 AIDS victims.

It was 25 months later, however, before he received his first -- and only -- payment, an emergency check of $747. Through what lawyer David R. Dwares calls "a comedy of errors," the other promised funds, which could have financed Johnson's visit home, did not arrive at his house until after his death on May 25.

"Most people with AIDS don't realize they can get disability benefits," said Dwares, whose law firm, Ross, Dixon & Masback, handles pro bono cases for the Whitman Walker Clinic in Washington, which cares for AIDS victims. Instead of filing a lawsuit over Johnson's case, Dwares and Mary Johnson decided to press the Social Security Administration into changing its procedures so that other AIDS victims can get help more quickly. "That's a big goal for us," he said.

After King read a 12-page letter outlining what Dwares believed went wrong in Johnson's case, she said she immediately agreed that the agency needed to improve its procedures.

"One of things we need to do is to identify better when people with terminal illnesses come to us, when time is of the essence," she said in an interview. "We've got to be very sensitive . . . and provide the kind of quick processing that is needed when terminal illnesses are involved."

Enoff said yesterday that the new rules, which will give guidelines of how quickly an expedited claim should be handled, can be implemented by the end of the month through administrative directives.

"You can't put a specific timetable on each case," especially ones that require the production of additional medical evidence, he said. But the rules "will ensure that people are sensitive to this . . . and that people listen," he said.

According to Dwares, the only person who appeared to be listening to Johnson's troubles was his 29-year-old niece, a supervisor for a satellite communications company. She would travel more than 100 miles a day between her Gaithersburg house, her Northern Virginia job and her uncle's hospital bed in suburban Maryland. "There were a lot of times I was just worn out, but you do what you have to do," she said.

Throughout his final months, Johnson said she never asked how her "Uncle Pete" contracted his illness and that she saw him cry only once. He did become angry over the government's failure to send him any benefits, she said, but he was not bitter over his fate.

Johnson was "the only father some of us have known," she said. He came to Washington in 1960 to help her mother raise her family and worked steadily at his restaurant job, taking time off once a year to visit his relatives in South Carolina, she said.

He had exhausted his life savings by the time he was hospitalized and had used what insurance money he had to pay medical bills, she said. The Social Security payment that arrived after his death will go to Johnson's relatives in South Carolina, Dwares said.

Dinah Wiley, assistant director of legal services for the Whitman Walker Clinic, said she applauded Social Security Administration for attempting to speed the processing of AIDS disability claims. "At the same time, I'm a little bit skeptical about the capacity of an enormous bureaucracy to achieve what they have expressed to us to be their goal," she said.