For union president George R. Davis Jr., yesterday's wildcat walkout bluntly underscored a truth he long had recognized: his powerful transit workers' local could no longer control its frequently embittered and unruly members.

"You have employes who are hellbent on hell-raising," Davis, who heads a local representing about 4,500 Metro bus and subway employes, said during an interview in his Indiana Avenue NW office. "I don't have the answer to it."

For hundreds of bus drivers, subway mechanics and other Metro workers who walked picket lines and brought the Washington area's transit system to a halt yesterday, a similar truth was apparent.

Nancy Wimbush, who normally drives a Metrobus in Prince George's County, knew why she had refused to work. "It seems that we can only get what we want from Metro if we walk out," she said. "We cannot get it through negotiating because Metro doesn't understand that."

"It's conditions in general that got us out here today," said W. H. Crosland, a driver who usually mans a District of Columbia bus route. "We're caught between the company's rules and the union's rules, and the union doesn't back us up when trouble starts."

For the second time since May, Metro employes had launched a wildcat strike without sanction of their union leaders. A May 18 walkout was prompted by the rape of a female bus driver and was aimed at getting improved security aboard Metrobuses. Yesterday's strike was triggered by Metro's failure to pay its employes a cost-of-living increase that would normally have been put into effect July 1. The union's contract expired April 30 and a new one has not yet been signed.

In both instances, the events that set off the work stoppages raised key issues, inspiring strong views among many Metro employes. Both walkouts also brought into focus a series of other unsettling undercurrents that have long troubled the Washington area's transit workers and their union labor organization, Local 689 of the Amalgamated Transit Union.

The cost-of-living increases have long been a central issue both for Metro's employes and for the transit agency itself.

Metro workers and their union view the wage escalator - which provides increases virtually equivalent to raises in the Labor Department's Consumer Price Index for the Washington area - as their primary means of trying to keep pace with inflation. "It's the only thing we've got," Local 689 president Davis said yesterday.

Metro's management regards the cost-of-living clause as an over-generous benefit that adds millions of dollars annually to the transit agency's soarinf deficits. They have objected to it ever since it was imposed on the agency through a controversial contract negotiated by the old D.C. Transit System shortly before Metro took over the privately owned bus company in early 1973. Congressional legislation compelled Metro to retain the escalator.

The May 13 walkout prompted by the driver's rape touched on deeply rooted feelings among many bus drivers, who complain that they are subjected to constant harassment and abuse by disorderly passengers.

Similiar sentiments were echoed yesterday in [WORD ILLEGIBLE] veins. "A lot of people think we make a lot of money when they hear we're being paid $16,000 $20,000 with overtime," one driver, Troy Mauleby, asserted. "But they don't have to get out here and down the U routes. They don't get up [WORDS ILLEGIBLE] in the morning and get back [WORD ILLEGIBLE] and 9 at night."

In an era of widespread labor unrest and union dissidence here and throughout the United States, no single worker appears to explain why union members strike, and few labor or management officials fully agree on [WORD ILLEGIBLE] of their sometimes parallel predicaments.

Peter J. Sheehan, a labor relations specialist for Metro, cited the youthfulness of Metro's current employes as a key factor in rank-and-file union dissidence. More than half the members of Local 689 have held jobs at Metro for seven years or fewer. The younger members, Sheehan noted, often lock faith in labor leaders and have more traditional sense of pride in their work. "The older people also know where they were - and where they are today," he added.

Another factor citied by union and management officials yesterday was the Local 689 has only five full-time [WORD ILLEGIBLE] and shop stewards, said to be a relatively small number, to manage a large and, sometimes large membership.

In addition, both Metro and Local 689 officials contend that yesterday's wildcat walkout was organized by a small militant faction that has exploited the broader concerns of other Metro workers.

The relatively small group is inciting this thing, and they're getting followers," local president Davis complained during yesterday's interview. He said he shared some of their objectives, move significantly retention of the cost-of-living escalator, but opposed their tactics. "You can't support a legitimate gripe by illegitimate action," he said.

Apparent explanations for why Metro employes joined in yesterday's strike ranged from economic and other complaints to such simple elements of human motivation as the pressure of their peers and, in some instances, clear intimidation.

"I wanted to go to work this morning," Dustry Rhodes, a bus driver, said. "But they told me that if I went to work, I wouldn't have a windshield in my pickup when I got back." Elsewhere, a group of striking bus drivers halted a Metrobus as it passed by and ordered its driver and about 20 passengers off the bus. Those on the bus were eventually rescued by police.

Drivers reiterated long-standing complaints. They said they were often ordered to drive unsafe buses that had not been properly repaired. They said the bus system was considered merely a stepchild to the more glamorous subway system. They complained of various forms of racial and other discrimination.

Some bus drivers also asserted that their jobs were endangered by the Washington area's increasing reliance on its subway system rather than its bus system. "Our jobs are being done away with inevitably," one driver said. "Every time they open a new subway line they terminate a few more (bus) runs."

Metro officials flatly dispute this view, saying that the transit agency is expected to operate virtually as many buses in 1990 as it does today.

In Prince George's County an 18-year-veteran of the bus system's maintenance shop contended, "We get the worst buses, the ones that are ragged and beaten up. We can't get proper parts and we can't get the number of mechanics that we really need."

Amid the gripes, some Metro workers als expressed concern that their strike had inconvenienced the public. "Most of the guys here are sad because you know you're hurting your passengers," said Ray Wooten, a driver in Arlington. "It's just the old story - you can't be pushed too far."