Mauston police assisted Juneau County authorities with a motor vehicle accident Sunday morning.  The officer said about 5am he responded to a motorhome that had started on fire along Highway 82 near 19th Avenue east of Mauston.  The driver of the 1985 Toyota Coachman motorhome, 53-year old Catherine Acton of Ironwood, Michigan, told the officer the brakes had locked up and she was unable to maintain control.  The vehicle entered the ditch and struck a ‘no passing’ sign breaking the post near the ground.  A small fire started in the passenger side rear tire well.  The officer and Acton used fire extinguishers to put out the fire.  The Mauston Fire Department was called to the scene as a precaution.  The driver was uninjured.  The motorhome sustained minor frontend damage and a broken rear axle.