Kenmore sewing machine models with bad plastic gear or Bushings

148.12180

148.12190

148.12210

148.13022

158.12271

158.12470

158.1680x

158.1787180

158.1780x

158.1880x

158.1980x

385.15718500

UPDATE 10/20/2023 - I only learned the belt pulley by the handwheel, on SOME versions of the 1603, 1703, 1803 models, can be dark brown plastic , thanks to Joe Winchester, in one of the Vintage Kenmore groups on Facebook.  
Joe Winchester discovered a brown plastic pulley on his 158.18033, and asked group members to check ours. I found plastic pulleys on an 158.18130 (newer than 1603, 1703, 1803 models), one 158.18033, and one 158.17033, but other versions of these same models, both 17033, and 18033, which I worked on, had aluminum looking/metal pulleys. 
The earlier models of 1603, 1703, 1803, which will had a 0, 1, 2, and SOME 3, for the version number, 158.1603x, 158.1703x, 158.1803x, the pulleys are aluminum, or another metal.
I DO NOT consider 1603, 1703, 1803, or 1813 as part of the DO NOT BUY list, even with this possibility, none of my plastic pulleys are cracked, probably because I prefer cleaning old oil out, then oiling, and I do not usually use heat to free up frozen machines, only as a last resort, and not anywhere that metal and plastic are together. (I do mention using a blow drier for short times in specific videos on certain machines, but I prefer cleaning, to risking damage by using heat.)
If anyone has used heat to free up a frozen machine (as many people recommend in online groups), and if it has one of the plastic pulleys, it is more likely to crack sooner.

158.12470 bad plastic zigzag actuator gear. Machine straight stitches still.

Cheaper, deeper plastic knobs, and typically side loading bobbins are telltale clues to early models with plastic gears,  like 158.12470, and 158.12270

158.12470 Kenmore Maruzen bad plastic gear on top 

Kenmore sewing machine model 148.12210 has a plastic gear in the top of the machine, under the zigzag actuator.  Both myself, and a friend, both acquired this same model of Kenmore sewing machine, within weeks of each other, we both purchased metal replacement gears ($26), and while dismantling the parts to install the new gear, we BOTH had the same pot metal part break!

The broken gear, and the gridded metal part it broke off of.

Angie used Gorilla Glue to successfully  repair that part, but I parted outthe machine, since I had other better models, in need of the pedal, tension unit, and various other parts. The 1221 only has a few stitches, so the sacrifice to save other, better built models, with more stitches, was well worth it.

I will add more models as I learn about them. Luckily, there are not many Kenmores with these bad plastic on metal gears, designed to break.

Kenmore 148.12210 Metal replacement gear ($26) is in the plastic bag on the machine bed
The broken plastic gear is barely visible under the zigzag actuator slide, the white plastic is butting against the front of the machine, under the spring.

Kenmore 148.12210 top view, note broken plastic gear at the front under the curved zigzag actuator slide.

Pot metal part which broke, during the gear replacement. My hubby broke this one, accidentally, my friend, Angie had the exact same part break on her, during her replacement of the broken plastic gear in her 148.12210 Clearly, I don't recommend this machine, knowing it has 2 such horrible weak spots. They are, however, excellent parts donors, for the hingepins, tension units, pedals and cords, bobbin hooks, and any other parts which can be harvested to help fix other better built Kenmore sewing machines!

Another view of the part which broke, it literally snapped off. Angie was able to glue her parts back together with Gorilla Glue, and the machine worked fine, so it is fixable, but I had so many other good machines that needed the various tension unit, pedal and cord, presser foot, bobbin hook, etc., that I turned this one into a parts machine.

148.12210

Another view of where the broken part snapped off 148.12210

While I decided to make this Kenmore 148.12210 sewing machine a parts machine, my friend was able to continue to use hers, with her church group, sewing for charity. The Kenmore manufacturer, Soryu, must have either realized that the easily broken gears weren't worth using in future machines, or I suppose, having a few of their models break down too soon, so they had to be repaired, could possibly be why Sears switched to Maruzen for manufacturing later Kenmore sewing machines, I don't know, but I am grateful that most vintage Kenmores do NOT have this poorly manufactured of parts. For the most part, the MANY  vintage Kenmore sewing machines I have enjoyed fixing up and servicing, and sewing with, are extremely well built, easy to use sewing machines, once you master the basics of sewing with a sewing machine.

I also acquired a 158.12470, which also has the bad plastic gear, which was cracked. These make great donor machines, however. 

158.12470 has bad broken plastic gear on top

158.12470 top gear plastic broken

158.12470 broken plastic gear

Both the 148.12210, and the 158.12470 are low end machines, with only a few stitches built in, so it isn't as big a loss, to not repair them, as I would consider a model with more built in stitches, and cam capability. I would rather part these machines out, to fix more useful, better built machines, which make their way to me, just missing parts!

PLASTIC BUSHINGS-

Not many vintage Kenmore sewing machines have crappy plastic parts, but newer ones, do. If you have a newer plastic sewing machine, which is nice & lightweight, it probably has the plastic gears and bushings, which eventually crack and break, especially if you try to sew anything heavy. This is NOT worth repairing, the cost of parts and repair would be more than the machine cost new.

Kenmore 385.15718500 sewing machine skips stitches caused by cracked main cam Part 1 & 2

158.1880x model 1880

The Kenmore 158.1880xxx (all 1880 models, as far as I know) is a luxury model freearm, which takes the C cams (orange, and grass green), and came with a rear mounting buttonholer, and monogrammer, but HAS A BAD PLASTIC GEAR, in the underside of this front location freeaem, unfortunately. It has a drop in bobbin system, another clue that it is one of the newer models, as built in obsoles ence crept into our beloved Kenmores, again.

158.12470 bad gear, side loading bobbin,
Cheap deep plastic knobs, few stitches

158.12270 cheap plastic knobs, few stitches, side loading bobbin

158.12270 cheap plastic knobs, few stitches, side loading bobbin