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How to Change a Singer 338 Sewing Machine Belt

This is a small departure from my more recent computer centric posts, but I thought it was worth posting, since most of the directions online are text only. I’ve changed belts on Singers with external motors before, but this was my first time changing an internal belt. This post should probably help anyone with a Singer 327/328, a 337/338, and a 347/348, since they’re all very similar machines. The basics should be the same for other Singers from the same era, and probably some other brands as well.

The first thing to do is to lay the machine on its side, taking it out of the cabinet or the bottom of the portable case if you have one. I like to lay mine on top of a folded towel. Look at the side with the hand wheel. On the 338, there are two large screws on the side panel. You will need to undo these. I also took off the top of my machine, but I think that was probably unnecessary.


Pretend you’re looking at a torn and tattered belt. I forgot to take before pictures, so you’re looking at my shiny new belt here. The next thing to undo is the chrome part in the center of the hand wheel (what you normally loosen before winding bobbins). You will have to first unscrew the tiny little stop screw, then unscrew the entire chrome piece until it comes out.


Now it’s time to take off the oil drip pan (if your machine has one, it’s the plastic piece that covers the bottom of the machine, generally attached with a single screw) and undo the bottom motor mount screw. On the 338, the screw for the motor mount is in a tight spot that you can only get to through the cutouts in the bottom side of the machine. The screw passes through two nylon washers, which are divided by the metal piece that actually attaches to the motor.

Here’s how I unscrewed it:


And here’s another peek, so you can see what I’m talking about. Nylon parts in old Singer sewing machines are always that white beige color.


Once it’s unscrewed, the entire motor mount will move freely up and down. You only have to nudge it a little towards the top of the machine, though, so before you get too crazy, go ahead and pull the hand wheel away from the body of the machine just enough to expose the top of the belt.


Remove the old belt (if you haven’t already) and place the new belt in the hand wheel groove. Push the wheel back into the base of the machine and loop the other end of the belt over the bolt like protrusion that sticks out of the motor. The second picture I posted above shows a correctly installed belt. You can go ahead and screw the hand wheel back on to secure it, but don’t put the side panel back on until after you reattach the bottom motor mount screw and its two nylon washers. The motor will be under tension from the belt, so this can be a little tricky. Try not to screw it in crooked. I put my left hand in through the open side panel and maneuvered the motor into position that way. Nylon parts get brittle with age and can break, so just be careful of the any white plastic pieces inside your machine.

Once the belt is securely in place, turn the hand wheel and make sure everything works. If you can’t get the chrome center part of the hand wheel to tighten correctly (the stop screw hits the washer underneath too soon before the chrome part is sufficiently secure), the in between metal washer that sat between the chrome disk and the hand wheel may have been put in the wrong way around. Flip it 180 degrees and try again. (It has two flanges that want to sit in cut outs facing into the hand wheel, but there’s nothing to show which way is correct.) If everything looks good, put the oil pan back on, put the machine back in an upright position, and try sewing.

13 Responses to “How to Change a Singer 338 Sewing Machine Belt”

  1. Lila Says:

    Thanks for the post! I have a 337 and a new belt waiting to be installed.
    Now with this encouraging post, I can try !

  2. Patty G Says:

    Thanks. It showed me exactly what I needed to change the belt in my Singer 347. Success!

  3. Patty G Says:


  4. Joan Cobb Says:

    Hi This is great, but how about if it is the pulley. Mine 328 Style-o-matic is running so stiff.
    It makes a humming noise and is still even when I try to turn the wheel by hand to get it going. Once it start it sews great, but sure strains and is so stiff and it gives off a hot smell a little bit.
    I can’t even find a listing for a new or good used pulley. The pulley seems to wobblle a little when it runs, It belonged to a dear friend who dies and wanted me to have abd use it. Can you help? Joan

  5. diastelo Says:

    I’m not a sewing machine repair person, just a computer nerd who knows a little about mechanical things, so I’m not sure what you mean by pulley in this context. (I know that if the belt is too tight or the wrong size, the machine can tighten up, and the extra friction can cause what you’re describing. Likewise, a too loose belt can lead to slippage and have similar symptoms.) If the part you are describing is a piece of loose metal that can be removed, it can sometimes be replaced without much effort. I would recommend you try a local repair person or if you’re feeling adventurous, attempt to remove the pulley part entirely and ensure that no screws or threads are stripped or missing. Replacing a screw is fairly cheap. By pulling the misbehaving part out, you may also discover a part number that would make it easier to track down a replacement. Nearly any part is available thanks to the Internet, but sometimes only with the help of a donor machine. I hope this helps.

  6. Marek Says:

    Thanks so much for info. We just got a 2nd hand Singer 348, exactly the same as my mother’s, and it now works like a charm!

  7. Amie Tarpley Says:

    Thank you for this tutorial! I’m getting ready to bid on a 338. I wish I could here it run but nobody I know has one. Can you tell me what it sounds like?? I’m prob going to bid anyway but would love to know if it sounds like a plane taking off or quiet and smooth :0) Amie

  8. diastelo Says:

    It sounds like most belt driven mechanical sewing machines. The motor is very audible and will drown out, say, the TV, but it’s a relatively smooth engine noise. It’s a lower pitch than a vacuum cleaner. (The slant needle Singers made around the same time are a little quieter, probably because they aren’t belt driven.)

  9. Doris Rigby Says:

    Thanks, just fixed my cousin’s machine with your instructions. Now she can finish sewing fer great-grand baby’s blue Jean quilt. Thanks again.

  10. Raman Patel Says:

    Thanks I have read your instruction and I will try to change belt on Singer 418 witch looks same as the picture that you have posted. I will let you how it come out.

    Raman Patel

  11. Treadle-izing My Singer 328K | Grow Your Own Clothes Says:

    […] removing the plug, the motor belt needed to come off. I found this blog post that helped me figure out how to get the motor belt […]

  12. Lynda Hawkins Says:

    Thank You, I bought a treadle sewing machine cabinet that had this singer 338 machine in it.
    I wanted the cabinet but was glad to get the machine, but it wouldn’t do anything but hum. I didn’t know if the motor was out or not, but I ordered a belt off ebay and thanks to your post I was able to replace the belt. I’m a 71 year old and am real proud of myself.Now it works. Thank You again.

  13. Singer Model 338 Sewing Machine Green from 1964 Says:

    […] the belt in one of these machines here is the link to the video showing you how to do that.  http://www.diastelo.org/blog/how-to-change-a-singer-338-sewing-machine-belt/ Now I can sew tomorrow. I have so many projects to work on. Of course, I could sew anytime I have a […]

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