The right to hire part-time Metrobus drivers is a key goal of many Washington area politicians and an important part of the negotiations between the Metro Transit Authority and the Amalgamated Transit Union Local 689.

The contract between Metro and about 4,800 bus drivers, subway operators, mechanics, station attendants and clerial employes expires April 30.

Both sides are pledged to submit unresolved issues to binding arbitration. That means there is little likelihood of a bus and subway strike here if a new contract is not ratified immediately. In previous years, however, there have been occasional, brief work stoppages despite the binding arbitration clause.

Representatives of both Metro and the union declined to discuss the progress of negotiations or the specifics of given issues.

Walter Bierwagen, an international vice president the transit union and a key negotiator, said, "We want to maintain and improve our standard of living . . . We have made concessions in the past that have saved (Metro) thousands of dollars annually, and we have achieved less than equity in our wages."

Bus drivers are guaranteed a minimum of eight-hour days and 40-hour weeks. Those at the top of the salary schedule receive $8.16 per hour. The rates for other categories of employes are figured as a percentage of the top bus driver rate.

With overtime and extra pay for night work, the average fully experienced bus driver can earn about $20,000 annually, both Metro and union representatives estimate.

"Part-timers," Bierwagon said, "are not an asset to the industry . . . I haven't seen anything yet (in these negotiations) that would be persuasive on the issue. But we'll listen."

Joseph S. Wholey, Metro Board chairman, called the part-time issue "important." "Many drivers do 6 1/2 hours of productive work and are paid for 8 hours or 9 hours. Obviously this is something we should work on. We hear about it from the public, from state legislators, etc. I don't know how big a priority part-time drivers would be in given year, but to me it's an important thing."

Another central issue, it was learned, is the cost-of-living escalator in the present contract. It calls for the drivers salaries to be adjusted quarterly and to increase point-for-point with the Consumer Price Index. During the two-year life of the present contract, the hourly bus driver wage has increased from a top of $7.40 to $8.16 solely because of the cost of living escalator.

However, under an arbitrator's award, the drivers lost the escalator in the first quarter of the existing contract, and some of them are still angry about that.

Metro would like some moderation in the cost-of-living increases it must pay; the drivers obviously regard any cut in the cost-of-living escalator as retrogressive.

Other issues include health and welfare benefits, sick leave and vacations. Some changes in work rules are also being discussed, as are some job definitions for subway operators and mechanincs as opposed to bus drivers and mechanics.