Metro's brand-new smaller buses, launched in September to reduce noise and vibration on narrow District streets, have screeching brakes that make them louder than the large buses they replaced.

Metro will spend about $32,000 to change the brake linings on the 40 new buses in hopes of quelling the noise, which has been measured outside the bus to be up to 130 decibels--louder than the noise heard on an airport runway or in the front row at a rock concert.

As a rule, transit buses shouldn't be louder than 83 decibels, said Phil Wallace, Metro's acting general superintendent for bus maintenance. "It's annoying," Wallace said, describing the sound of the new buses.

"The unhappy irony of this is that the promise of these buses was a greater amount of silence," said Jim Graham, a member of the D.C. Council and Metro board of directors who has fielded complaints from city residents about the bus noise. "But in actuality, they're providing more noise. Brakes should not screech the way these brakes screech."

Metro bought the new buses, at $218,000 each, to use in older District neighborhoods where streets are narrow and conditions too cramped for more traditional buses. The new buses, built by Orion Bus Industries Ltd. of Ontario, are 26 feet long. Most Metro buses are 40 feet long.

Paul Royal, Orion's executive vice president, said he was not aware of other transit agencies that have experienced noisy brakes on Orion buses. He said Orion extensively tests its buses before they are sent to customers.

The linings and the drums on the brakes of the new buses do not line up perfectly, which creates vibration and subsequent noise, Wallace said. The brake lining material is especially hard, making the vibration worse, he said.

Although the buses are still under warranty with Orion, Metro has ordered new softer brake lining material from another company, Wallace said. He said Metro has retrofitted two of the new buses with the new brake lining material and it appears to have solved the noise problem. Work on the rest of the fleet is expected to be completed by March, said Jack Requa, Metro's chief operating officer for buses.

The transit agency will try to recoup its costs from Orion, Wallace said. "We'll fight the fight," he said. "It's not over."

But that was news to Orion. Royal, the company's vice president, said Metro has not asked Orion to replace the brake linings or pay for new linings.

Many transit agencies across the country are using the smaller buses on feeder routes and for special services, such as transit for the disabled and senior citizens. Metro is among the first to use the buses on its heavy-duty routes, where braking is frequent, Wallace said.

"The only other vehicle that gets heavier use is the garbage truck," Wallace said. "It's pedal to the metal, brake, pedal to the metal," he said. "It's a very harsh-duty cycle."

In addition to the braking problems, Metro said the air conditioning on the new buses is not effective. The air conditioners are supposed to provide 82,000 British thermal units but are able to reach only about 55,000 BTUs, he said. Metro wants Orion to fix the air conditioning at no cost to the transit agency.

Metro also will install additional poles in the front of the buses, after passengers complained about a lack of poles for riders who have to stand.