basic am radio in '70 Duster

Is it easy to fix the tuner knob? I can turn the knob but the red dial will not sweep left or right to find stations. I was lucky that the preset button to the far right was set to a station on tht side and the dial was full left. I was able to ,very carefully, use the preset button to slowly sweep across and set a few more stations on the presets. I'd like for it, tuner knob, to work as intended. Any advice or help appreciated. It is a good working radio otherwise and I just replaced the speaker.....sounds good for what it is. thxs again!