A common failure occurs when a Singer sewing machine breaks behind the handwheel disengaging clutch. Often a "W" shaped spring falls out when this happens and the motor and Handwheel spin but the machine doesn't function.
Step 1: Remove the Top Cover.
Remove three screws from the machine top and disassemble the top cover.
Step 2: Remove the Side Cover.
Remove one screw to disassemble the side cover.
Step 3: Remove the Side Cover.
Remove one screw at the motor side and disassemble the side cover.
Step 4: Remove the Setscrew and Lock Ring.
Remove the setscrew, lock ring, and outer handwheel from the Clutch.
Step 5: Inspect the Clutch.
Compare the new white clutch to the broken yellow clutch. Notice the plastic is broken on the left side edge.
Step 6: Replace or Repair the Broken Clutch.
1) Order replacement part number 357367-901 "Hand wheel disengaging clutch engaging plate cover" then skip to next step. (I found one on Amazon.com for 10 bucks).
2) Repair the broken plastic part:
a. sand the plastic around the broken area.
b. Mix JB Weld plastic epoxy and build up the broken area. Multiple applications may be required to build up sufficient material.
c. Use a file to shape cured epoxy into a new drive tooth as shown in the pictures. The tooth should be square sided so it can run the sewing machine clockwise and counterclockwise.
d. Test the tooth size by fitting it into a slot in the handwheel.
Step 7: Select an Upgraded Spring.
Shame on Singer for designing such a flawed clutch system. That "W" shaped spring is rediculous! A simple upgrade can be made by procuring a spring similar to the one shown in the pictures. A dead printer can be disassembled to harvest a dozen of these if necessary. Clip the spring to the length shown. Take care to select a spring that is just strong enough to make pinching it with two fingers slightly difficult.
Step 8: Assemble the Spring, Metal Tube, and Clutch Plate Using the Plastic Pin.
Use the plastic rod to go through 1) the plastic support, 2) The metal tube side, 3) the spring with the short side in the tube and the long side opposite the plastic tooth. Use pliars or tweasers if needed to get the spring into place, 4) the other tube side, 5) the other plastic support side. Add a little hot glue to the pin if needed to ensure it stays in place. The metal tube should now be held leaning toward the plastic by spring force.
Step 9: Reassemble the Handwheel.
Reassemble the Handwheel by pushing the metal tube through the handwheel and replacing the setscrew and lock ring as shown. Take care to ensure the setscrew does not extent inside the tube.
Step 10: Reassemble the Handwheel Onto the Shaft.
Take note of where the flat side of the drive shaft has the setscrew hole. Install the handwheel taking care to pull the plastic front cover free. Align the setscrew over the shaft hole and tighten the screw. Also re-assemble the drive belt as shown.
Step 11: Reassemble the Side Plate and Top.
Replace the side cover and tighten the one side screw. Replace the top cover and tighten the three top screws.
Step 12: Replace the Top Cover.
The machine is now fixed in a way that is better than new!!
If the repaired part breaks just order a new part and do this again!!
Disassessembly and reassembly only takes 15 to 20 minutes!
Here are a few other part numbers that may come in handy:
Plastic pin: 357364
Retaining lock ring: 446387
Step 13: How to Install the Original Manufacturer Spring
I got a new spring and part so I am adding this note to augment the information above.
1) Push the straight end of the "W" spring thru the plastic hole.
2) Push the metal shaft post into place taking care to place the "W" spring in the lower groove as shown.
3) Push the plastic pin into place.
DO NOT ALLOW THE METAL POST TO MOVE YET. KEEP IT AIMED AWAY FROM THE PLASTIC TOOTH. FAILURE TO DO SO WILL RESULT IN THE SPRING FALLING OUT OF THE GROOVE.
3) Install the metal post into the belt driven handwheel and push it in all of the way before allowing the spring to move.
4) get the snap ring installed on the post to keep it in the handwheel. the new "W" spring should now allow the plastic part to actuate between locked and unlocked.
5) All other steps are provided above.