Starting Monday, the bells at Minneapolis City Hall will stop ringing as workers reinforce the bell support system.

The work will last about three weeks, which should bring them back in time for Christmas Day.

The support system, which is as old as the building, holds the tower’s 15-bell set. The bells vary in weight from 300 to 7,300 pounds. Renovations will focus on supports for the largest bell, where the steel plate between the bell and supporting timber has deteriorated, according to the city.

The Municipal Building Commission Historic Preservation Fund will pay for the $130,000 project.

The commission has served as the steward for City Hall since 1904. Free tours are available the third Wednesday of every month at noon.