As he quick-stepped down the long corridor in a manner that belied his age, the FBI agent straightened his blue club tie and brushed off what little lint there was, if any, from his immaculate steel-gray, double-breasted suit.

He greeted his visitor with a firm dry handshake. With the precision and advanced preparation that has become his trademark, Edward J. Armbruster, 85, the oldest working special agent that anyone can remember, recalled with relish the glorious days of the bureau when J. Edgar Hoover whipped a scandal-ridden agency into one that, for five decades, became synonymous with order and decency in America.

"Mr. Hoover was strict - he didn't allow any foolishness," Armbruster remembers. "If you were a minute late for an appointment with him, he wouldn't see you - the door would be closed.

"And he had a strict rule about dress, too," said Armbruster, a teetotaler who never smoked. "He was a stickler fro appearance - we always had to be clean-cut and presentable enough to meet anybody. He didn't let people go around without hats, either."

To this day, Armbruster still wears a hat - a dark gray fedora "like the kind that Mr. Hoover wore."

And like Hoover, who used adherence to the most minute details as the barometer of discipline within his department, Armbruster follows a regiment that is older than some of the agents he works with.

"Mr. Hoover taught us there is a right way to do things and a wrong way," Armbruster said. "We had to be sharp, on our toes and prepared.

Every day when I go to the office, I make a card of what I am going to do and what I am going to see - like a plan for the day," he said.

When Armbuster was interviewed recently by a reporter, he had prepared note cards of exactly what he planned to say.

"I keep a diary and have done so since 1924. Years ago, when I participated in a trial in West Virginia, an opposing attorney accused me of being in a certain town trying to get evidence from an individual," Armbruster said. "Forutnately, I had my diary with me and I could show them in the diary where I had been and who I had seen. When I pulled out the diary, it floored them."

In admiration, and sometimes in awe, FBI agents, many of whom are young enough to be Armbruster's grandchildren, call him "the Grand Old Man of the FBI," and "a living legend."

Nick Stames, the agent in charge of the FBI's Washington field office where Armbruster works, said, "I'd put Armbruster in the FBI's Hall of Fame, if we had one."

After 51 years of service - three years longer than the legendary Hoover, Armbruster has worked longer than any other federal law enforcement officer will ever be able to because of a law passed by Congress recently that prohibits law enforcement officers from working past age 55. The same law will force Armbruster to leave the department next month.

It won't be retirement, however, Armbruster already retired in 1962 at age 70. On the day after his retirement the bureau reappointed him as an "annuitant," allowing him to keep his position as an accountant investigating white collar crime. Since then, his salary has been the difference between his pension and a regular salary, about $13,000 a year.

He says there are no regrets about leaving. "It's time that I say goodbye and enjoy what I have left of retirement."

His friends say privately that it's not strange that he would say that. They say that throughout the years that he has worked at the bureau, Armbruster would never think of complaining or criticizing the agency whose work has occupied nearly two-thirds of his life.

Armbruster still lives the memory of the Hoover era - the days of G-men and Machine Gun Kelly - despite the changes in the bureau.

He notes the wearing of "longer hair," and the more relaxed attitudes in the department, but is noncommittal.

"I don't know if I regret the changes," he said. "I jut like the way that I am.

"Mr. Hoover instilled in me a feeling of loyalty and doing a job the right way," Armbruster said. "In 51 years I have never been angry with the department."

The allegations that some of the former agents have made in the past four years make me sick - people seem to be throwing all the dirt they could find and that really hurts me," said Armbruster, who is defensive about charges that the agency abused its power unlawfully during Hoover's 48 years as director and about criticism that Hoover had unquestionable control over his agents and their private lives.

"Mr. Hoover was a genius," Armsbruster said. "Regardless of what was later said about him, the FBI wouldn't be what it is today without his leadership."

Armbruster, sometimes affectionately called "Army" by his co-workers, remembers the excitement of the early years in the FBI's history - the days of gun battles with notorious gangsters that built the solid reputation of the FBI as a crime fighter and the stalwart of decency.

But as an accountant who eventually became an expert on bank fraud and other types of white collar crime, Armbruster never chased the infamous mobsters.

"I never hankered for that kind of work, and fortunately, the bureau never put me in it," he said.

"I was working on a case in Birmingham (Ala.) during the 1930s when agents surprised Machine Gun Kelly nearby," he said. "They found him in bed with a gun underneath his pillow and his bed, and he said 'Ok G-men, you got me,' and that's how we became known as G-men," Armbruster said.

If Will Rogers is remembered for his statement that he never met a man he didn't like, Armbruster, quiet, sometimes shy and always unassuming, may be noted for never making enemies.

"I don't believe in having enemies; if I make one, I always apologize," he said.

Armbruster said it's easy-going ways that have most helped him solve difficult cases.Once, when investigating a bank fraud, for example, he persuaded one of the bank's employees - a member of a Masonic lodge like himself, to tell him about the scheme to embezzle $500,000 from the bank.

Fingering 4-by-5 notecards filled with his life experiences that he prepared in advance, Armbruster was reluctant to identify the case or the individual.

"Their scheme was to use the money to buy certain minerals that were scarce during the war and make a profit, but they weren't successful in the venture and they didn't have a way to put the money back," he said. "I convinced the guy to talk to me, and later, I helped him get a shortened prison term for his cooperation."

Even today, Armbruster said, the man writes to him and sends Christmas cards.

Armbruster's success has come through years of quiet dedication built upon hard work and devotion to detail. Yet, that success came at a high price.

Much of the time, his work took him away from the same two-story Sears and Roebuck prefabricated frame house where he and his wife Grace have lived since they moved to Arlington as honeymooners 53 years ago.

"There were times when I was afraid for him. He was out of town a lot," said Mrs. Armbruster. "In those days, FBI agents didn't get paid very much and when he was sent on assignments, I couldn't go along - it was a matter of keeping up the home and pinching pennies."

As a result, Mrs. Armbruster said, he missed a lot of the time in which their only child, his namesake, grew up.

"I can recall one time when our boy said that father is just like a dream - he was gone so often," she said.

To other youngsters, however, Armbruster was the reality of achievement - a role model to emulate.

Forrest F. Burgess, An FBI agent who retired after a 40-year career, remembered Armbruster as one of his Sunday school teachers at Mt. Vernon Place United Methodist Church. Seven of the boys in Armbruster's Sunday school classes eventually became FBI agents.

"I remember that he was looked up to as a person with some degree of achievement," Burgess said. "Back in those days, it was status to belong to the FBI. Many people said that the FBI was the one agency that they could completely trust and had the highest regard for."

Another of Armbruster's Sunday school students, Montgomery County Judge Ralph G. Shure, 67, said simply: "I was always impressed with the man."