To disassemble a one-piece crank, start by removing the left pedal (turn it clockwise to unscrew it--everything on the left side of a one-piece crank is left (reverse) threaded.) Then remove the locknut
on the left side bottom bracket (clockwise to remove), lift of the keyed washer
, and unscrew the left cone
(clockwise to remove.) The left cone usually has grooves that allow you to turn it with a flat-bladed screwdriver. Pull out the ball retainer
, then you will be able to withdraw the whole crank assembly from the right side of the bottom bracket. Pull the crank part way out of the bottom bracket, then reach in and remove the right side bearing retainer. If you try to pull the corners of the one-piece crank through without removing both retainers from their cups first, you may damage the retainers. Clean and inspect the cones, cups and bearing retainers. If they are smooth and free from pitting
, you can re-use them. In most bicycle applications, bearings with loose balls are preferable to those that use retainers (cages.) One-piece cranks, along with headsets, are a major exception to this rule. It is extremely difficult to assemble a one-piece crank set with loose balls, I would not recommend trying.