Where it says "support the rear plate", that means you have to reach around the domed line enclosure with the fingers of one hand and pull the backing plate toward you while preventing it from twisting when trying to screw or unscrew the line enclosure. That plate slides along the shaft towards the motor, so if you just stop it from twisting without pulling it towards you (i.e. into the domed enclosure), then there's too much friction to be able to twist the enclosure. Of course forgetting to remove the tiny cotter pin also prevents the enclosure from being twisted off...

Thank You, Rich. I actually did get the thing apart without the manual but thanks for sure because it will come in handy.