Metro officials said yesterday they will consider changing the way the transit authority buys buses in an attempt to avoid problems similar to those stemming from Metro's controversial $12.5 million purchase of vehicles from Neoplan U.S.A. Corp.

"In hindsight," said Assistant General Manager John S. Egbert, a shift in purchasing procedures "probably would have been better."

Seventy-five of the Metro system's 76 Neoplan buses have been withdrawn from service after Metro inspectors found possibly dangerous cracks near the vehicles' front axles. One other Neoplan bus was demolished last December in a fire attributed to faulty electrical circuits.

Neoplan, a Colorado-based company affiliated with a West German bus manufacturer, was awarded a 1983 contract by Metro after a competitive bidding process in which the company offered the lowest price.

Neoplan has described its buses as safe and contended that Metro "overreacted" by removing them from service.

Metro officials said they would likely revamp their purchasing practices to provide more latitude to assess the quality of a manufacturer's buses along with their prices.

One possibility, Egbert said, is a two-step procedure in which the transit authority would seek to screen out inferior or untested manufacturers before soliciting bids.

Another option, officials said, is a form of negotiation in which the authority would conduct extensive discussions with competing firms.

Despite recent statements from Neoplan, Metro officials said they have not determined whether the buses could be repaired.

"There has been no technical proposal from Neoplan yet on what to do about the current problem," Egbert said.

In another development yesterday, Metro's board of directors adopted a controversial plan to equip half the buses purchased by the authority this year with special lifts for wheelchairs.

The move, approved over the objections of one Metro board member, D.C. City Council member Hilda H.M. Mason, fell short of demands by disabled riders, who have called for lifts on all newly purchased buses.

Metro officials have criticized the lifts, contending that they are costly and frequently malfunction.

The 1,600-bus Metro system now has 225 buses with lifts, including the 76 Neoplan vehicles that have been withdrawn from service for repairs. Of the remaining 149 lift-equipped buses, 17 had lifts that were out of order yesterday, officials said.

The lifts have long been a focus of controversy. Last fall, a Denver-based group called ADAPT, an acronymn for American Disabled for Accessible Public Transit, staged demonstrations marked by disruptions in rush-hour bus service to demand improvements in transit service for handicapped riders, including lifts on all buses.

An advisory committee representing elderly and disabled passengers recently urged Metro officials to adopt a goal of providing lifts on half the buses in the authority's fleet. To reach this aim quickly, the group argued, Metro should include lifts on all buses purchased in the next few years.

Under the Metro board's plan, the authority is to take several other steps to improve service for disabled riders, including an overhaul of existing lifts in an attempt to reduce malfunctions.

Officials also plan to study other possible changes in service for handicapped passengers.

In another development, Metro officials said they would increase the maximum value of Farecards sold at the Shady Grove and Judiciary Square rail stations to $30 as an experiment, starting Monday. The current maximum is $20.