The lawsuit filed in San Bernardino County Superior Court named as defendants the National City, Calif.-based Scapadas Magicas and Tijuana, Mexico-based Interbus Tours and Charters. The lawsuit also named the bus driver, Norberto B. Perez.
Guillermina Morales said she suffered two broken legs and a broken pelvis in the Feb. 3 accident near Yucaipa and lost the use of one arm. Her daughter, Pamela Morales, also broke her arm, according to the lawsuit.
The two are from Tijuana, Mexico, and are Mexican citizens.
Perez told investigators his brakes failed as he descended a steep mountain road while returning a busload of tourists to Tijuana after a day trip to see the snow in the San Bernardino Mountains.
No one answered the phone at Scapadas Magicas' offices in Tijuana and National City on Friday.
Jordi Garcia, marketing director for Interbus, said his company had not received the lawsuit and could not comment. Perez could not be reached for comment.
The Federal Motor Carrier Safety Administration earlier this month ordered Scapadas Magicas to immediately stop operating because its buses weren't properly maintained or inspected, and its drivers weren't properly vetted for qualifications.
The 1996 bus involved in the crash was carrying 38 people, including the driver and a tour guide, when it smashed into a sedan, flipped, slammed into a pickup and crashed on the way home from the mountain resort town of Big Bear.
Regulators said a post-crash investigation of the company's two other buses that had been operating in the U.S. found serious mechanical safety violations.
Inspectors said the company failed to have its vehicles regularly inspected before the deadly crash. When the buses were inspected, there were many violations, including multiple brake problems.
Vehicle maintenance violations were cited during 21 of Scapadas Magicas' 25 most recent vehicle inspections, and vehicles had to be placed out of service after 36 percent of the inspections, according to the order to cease operations.