Im a bit confused…maybe your teminology is a bit mixed up?
I’m a bit confused…maybe your teminology is a bit mixed up? The “pedal” is the part you step on. It screws into the “crank” with a left hand thread on the left side, and there’s no way to use a socket wrench on it…usually uses a thin 15 mm open-end wrench. I’m guessing that you really mean the crank is loose, where it attaches to the bottom bracket axle. This _is_ often secured with a socket wrench, most often a 14 mm or 15 mm. It is quite common for the left crank to come loose if it isn’t tightened enough. Then, if the bike is ridden while the crank is loose, the square hole in the aluminum crank gets deformed and the crank is ruined. Fortunately, left cranks are not expensive, usually about $20 for a generic replacement crank. Make sure to get the same length. The length will usually be stamped on the back side of the crank, usually 165, 170 or 175 mm. When you replace it, make sure you grease the square shaft, the threads of the nut or bolt and the pushing surface of the nut or
