Guide to replace the BLACK PLASTIC GEAR on TOP for Singer Stylist 457
STEP 1: Remove the top cover, as well as the left side cover. Remove also the bottom covers. You will have to remove the front cover. Keep all screws in a small container for re-installation. Remember these machines were built on the 1960's so treat all parts gently. You will have access to the black gear once the face plate is removed.After this, you are now ready to remove the broken gear.
STEP 2: REMOVING THE BROKEN GEAR. First, you will have to remove the timing belt tensioner and the timing belt underneath. Then, by inserting a long flat screwdriver in the illustrated opening, you will be able to remove the gear set screw. Note that I also removed the needle position lever which is retained by one screw, to gain access when removing the old gear and to reinstall the new one. This lever serves to adjust the center position of the needle.
Once the gear set screw is removed, you will have to pull the vertical shaft underneath. The broken gear will slip out of the shaft
. Do not remove the entire shaft. Pulling it approximately 2 inches is enough to release the black top gear.
You are now ready to install the new gear. If necessary replace its set screw with the old one.
Be sure also to clean the bigger (white color) gear which match the top gear. Check for any debris between the teeth.
STEP 3: INSTALLING THE NEW GEAR. Reinsert the vertical shaft so it is flush with the gear surface. With your long screwdriver, slip the new gear in it, and put your screwdriver blade in contact with the gear location (on top of the vertical shaft). Slip the gear to its original position while inserting the shaft slowly. This method is recommended instead of trying to place the gear with your fingers. The gear can fall at the back of the mechanism or fall down in the motor.
Hold now the gear with your fingers on one hand, and with the other hand, push the vertical shaft in place. Be sure the flat side of the shaft comes in contact with the gear set screw. Tighten the set screw firmly when the vertical shaft is completely inserted.
You are now done with the first part. Second part is placing back the timing belt and adjusting the needle-hook timing.