You might have to but then again maybe not. It depends on how much thread is there and how badly it's jammed up in there. My first 301 had a random issue of skipping stitches. I thought I had cleaned it really well but after checking the bobbin area 3 or 4 times I finally saw some pieces of clear nylon thread behind the base. With some patience, a flashlight and long skinny tweezers I finally got it all out without taking anything apart.
Cari