When I arrived at the 111W155 sewing machine seller's home to take a look at it, she said right off that "the belt broke". I naturally thought it was the main drive belt, not the timing belt. But alas, it was the timing belt. I assumed the upper main shaft had to be removed from the machine to get a new belt onto the shaft. I was taking a bit of a chance buying the sewing machine, not knowing how difficult (or easy as was the case) it would be to replace the timing belt, but I decided to take the leap. Below is a photo of the broken belt.
I ordered a new belt from an eBay seller for $19.95 with free expedited shipping. I got the new belt in 5 or 6 days.
All photos below are screenshots of a video I made to chronicle this endeavor, so they aren't that great. You can find the video HERE.
One other item to note, you can download a *free* owners manual for this sewing machine from Singerco.com. Navigate to their industrial machine section and you should find the link fairly easily (also below). The manual has steps on how to replace the timing belt.
Click here for 111W152_W153_W154_W155 manual
1. The first order of business in replacing the belt is to gain access to the upper shaft. Remove the hand wheel by removing the large end screw and loosening two small setscrews. The hand wheel may be tight on the shaft. I used a heat gun and a screwdriver to get it off. The photo below indicates the screw locations.
2. Remove the shaft bearing/bushing by loosening one setscrew on the back of the machine.......
...... and two setscrews on the bushing inside the machine (the owners manual failed to mention the two internal setscrews).
3. Slide the bearing out of the machine. I pried it out using a screwdriver, and a rag for cushioning.
4. Stuff the new timing belt into the hole. Be careful not to kink the timing belt.
5. Feed the belt through the hole and pull up and out the top of the machine.
6. Tada! That was easier than I thought.
7. Feed the belt down into the machine.
8. Here's the critical part, timing the upper and lower shafts. Position the takeup lever to its highest position........
........ and then align the two arrows under the machine. One arrow is on a metal tang and the other is on a bushing on the lower shaft. I'm pointing to them in the photo below.
9. Slip the timing belt onto the lower cogged pulley, being careful to not allow either shaft to turn. The belt should slide on smoothly and easily.
10. When installing the upper bearing, align the hole in the bushing (see photo below) with the hole in the machine so you can lubricate the bearing.
11. Slide the bearing into the machine and tighten two internal and one external setscrews.
12. Reinstall the hand wheel, noting that the upper shaft has a slot that one of the setscrews needs to screw into. Tighten the large end screw before snugging up the two setscrews.
That's all there is to replacing the timing belt. It was a 30 minute job. It would have taken less time if my hand wheel wasn't glued to the shaft with old dried up oil.