Mechanics will install metal plates on the undercarriage of the MBTA's newest buses to protect key parts from being scraped or split by rough roads, T officials said yesterday.
Ten of the buses need replacements for the 2 1/2-foot, 35-pound metal rods that connect their steering and suspension systems, said Joe Pesaturo, spokesman for the Massachusetts Bay Transportation Authority.
As engineers continue their inspections, more buses could need the replacements, he said.
The damage was found on some of the 21 buses that remain out of service after two steering-related crashes prompted the T to pull more than 150 of the buses off the roads during afternoon rush hour Friday, delaying thousands of commuters.
The metal properties of some of the damaged torque rods will be tested to see if they are defective, T officials said.
T officials will continue to inspect the buses daily and are advising drivers to report steering problems. T drivers are also asked to report potholes and other pavement problems that may have damaged the rods on the buses, which ride close to the ground to make it easier for disabled passengers to board.
''Some of the rods sustained major damage," Pesaturo said. ''It requires quite a hit to break one of these things."
The T is using replacement vehicles from its 1,000-bus fleet to cover routes of the buses pulled out of service.
The MBTA has 175 of the new Transliner AN440LF buses, which are 40 feet long and seat 38 passengers. The T was one of the first transit agencies in the nation to buy this model, which is made by Neoplan USA Corp. of Denver.
In March, the National Highway Traffic Safety Administration issued a recall notice for the buses after Neoplan reported a defect with other axle rods that control steering. T officials said that defect, which has been fixed, is unrelated to the new problem.