The steering column of the Audi A6 was restored a few weeks ago due to a reduction in the power steering fluid level and a roar when turning the steering wheel. The power steering fluid ran through the column rubber. The power steering fluid is now gradually decreasing. However, the steering wheel seems to turn a little harder. A quiet roar remained when the steering wheel was turned. When the power steering fluid is filled to the maximum, the steering wheel appears to rotate easier, but when the fluid falls, the display turns slightly harder. What could it be?