The controversial recall one year ago of the trouble-prone Firestone "500" radial tire may have been costly for the manufacturer, but it has brought unexpected riches to many local Firestone tire dealers, according to store and company officials.

"It's been my best year ever," said Bob Brinkman, manager of a Firestone store in Arlington. He said his annual sales are up a record 27 percent for the year and that he is retiring and moving to Florida with his profits.

"Business has been fantastic," agreed Larry Morgan, a vice president of Merchant's Tire & Auto Centers. Twenty-five Merchant's centers function as independent Firestone dealerships in the Washington area. Morgan said that sales some months have been up by 15 to 35 percent.

The reason local tire dealers have done so well is that when customers with "500" tires on their cars went to the stores with the recall notices, many found they were not eligible for free replacement because their tires were too old.

These customers qualified only for a prorated price on replacement tires. thus, if these customers wanted to turn in their "500s," they has to pay half or more of the new tire price. This translated into sales for the Firestone merchants -- albeit at a discount -- that the otherwise would not have made.

Another factor in the booming business was that many motorists who came in for replacement tires often had other services -- such as brake adjustments of front-end alignments -- performed at the same time.

Thus, while the Firestone corporation was hit with the cost of providing free or reduced-price tires under the recall order -- a cost that company spokesman Michael E. Fay yesterday put at more than $100 million -- many of the local Firestone outlets prospered.

Joan Claybrook, the chief of the National Highway Traffic Safety Administration who forced Firestone to make the recall, reacted to word of the increased sales by merchants here with a chuckle.

"(Ralph) Nader once said that the manufacturer benefits from a recall because it brings people into the store and they have a chance to sell them other things," she said.

Clarence Ditlow, director of the Center of Auto Safety, a Nader-founded group that fought for the recall, said he is not surprised by the increased sales.

"Firestone is laughing all the way to the bank," Ditlow said.

He described the tire sale increase as a "sad form of economic addiction" in which consumers who do not want Firestone tires are trapped into taking them because of the investment they already have made.

"What can they do?" he asked. "Pay $200 for another set of tires or go back to Firestone for half-priced or replacement tires which could fail again in the near future?"

Ditlow advocates a new federal investigation of possible defects in the Firestone "721," the replacement tire for the "500." In a formal petition filed with the highway traffic administration, the Center for Auto Safety contends that motorists have experienced serious failures with the "721."

The federal agency said that its tire-failure data "doesn't seem to indicate a basis for the opening of an investigation."

Firestone said the "721" has no defects.

Some store operators here were defensive about their success since the recall.

"The publicity was bad and hurt the Firestone name," said Rich Levy, manager of the Merchant's Tire store at 1141 Bladensburg Rd. NE. But he conceded that the recall "did have a good effect -- you see a lot of customers you wouldn't see otherwise and it gives you an opportunity to make sales."

Motorists who had their recalled tires replaced at Levy's store often requested front end alignments, he said. So even when a customer received free tires, he often ended up spending $16 to $18 on the alignment.

The sales increases at Firestone stores were a sharp contrast to the decreases registered at some of the stores operated by Firestone's local competitors.

Brian Bailey, manager of a Good-year store in Arlington, said his sales for the year to date are down 13.7 percent. He also said he understood how the tire recall could have increased sales for Firestone stores.

"If I could get a steady stream of cars coming in here, where I could spot something wrong with their car that needed fixing, I could increase business, too," Bailey said.

During the 12 months that the recall has been under way, Firestone company stores and Merchant's Tire centers here have replaced about 60,000 tires. The company has replaced about 3.7 million tires nationwide.

About 2.8 million of those, tires were replaced free. The other 900,000 were exchanged at half price or at a prorated price based on tread wear.

Claybrook contends that replacements are lagging because the company hasn't done enough to notify consumers about the recall. "We are not convinced that enough people are aware of the recall," she said. "We're asking Firestone to do another publicity campaign, but they haven't gone along with that yet."

Firestone officials said they had advertised the recall to major newspapers, mailed news released to major daily papers, sponsored television spots during network football games and sent letters to 3 million tire owners.

Tires eligible for free replacements have a five-rib or seven-rib tread pattern sold on or after Sept. 1. 1975. The five-rib treads must have been made prior to Jan. 1, 1977 and the seven-rib, prior to May 1, 1976.

Recalled tires are identified by serial numbers telling the date of manufacture.

Before Firestone stopped producing the "500" radicals in 1978, the company had made an estimated 24 million of the tires. They sold for about $50 each.

Concern about the "500" focused on a record of blowouts and tread separations. A congressional subcommittee determined in May, 1978, that the "500" had been the chief contributing factor in a large number of accidents.

At last count, the "500" has been involved in at least 41 deaths, 125 injuries and 3,300 accidents, according to the National Highway Traffic Safety Administration.

Firestone contended that the tire, when properly inflated, had no safety defect.

Consumers confused about the tire's safety and the replacement procedure jammed government toll-free hotlines for days after the recall was announced. "We were inundated with 10,000 telephone calls the first day, according to the telephone company estimates," said a highway safety administration official.

Unable to get through because of the busy signals, many people wrote letters. The traffic safety administration received about 250 a week at the height of the recall.

Now the hotlines has cooled and the letters have dwindled. "We get about 50 a week now and most are about refunds," said James Murray, the highway safety official who monitors the mail. Some requests for help in obtaining replacement tires still are coming into the government office, however.

The last one came from Allen Techer, a ninth grade teacher, father of two and resident of the small New York town of Mohawk, population 2,000.

"The Firestone dealer told me that maybe next year he would have replacement tires for me," said Techer.

Meantime, Techer plans to keep driving on the "500" tires on his Mustang II.

Washington area dealers surveyed said they knew of no local motorists in Techer's predicament.

"Some of my customers are driving on "500's -- but it's because they want to," said Bob Brinkman, the Arlington manager. He said many of his customers like their "500s" and plan to keep them until the end of the recall period to get as much wear as possible before swapping for replacements.

Brinkman opened the Arlington store in July 1960. He owns a 49 percent interest in it.

As a former State Department communications official who served in Bogota, Columbia in 1947, at the beginning of the rebellion there, he was ready when the tire recall was announced.

He put his full staff of 15 people to work to handle the crush of customers seeking replacement tires. "We extended the hours and worked nights and Saturdays," he said.

For each tire the store replaced, it received a $7.50 credit from Firestone to cover the cost of labor and wheel weights. In addition, the company provided the replacement tires.

Brinkman estimates that he replaced 6,000 tires at his store. The busiest times were from November, when the recall started, until mid-February.

"I made many new customers replacing those tires," he said.

The dollar increase his store amounted to about $300,000 for the year, he said. "And I can document that."

The year would have been better, he said, if it hadn't been for the gasoline shortage.

"I lost some repair business to the gas stations; people would leave their cars there for maintenance work -- and to get gasoline -- instead of bringing them to me."