My 1034D serger has a broken part that holds the lower looper.

First re-thread the machine starting with the upper looper(3), then lower looper(4), then the needles(2,1). If that doesn't fix it, it may be a matter of loosening the needle tension. Lastly slowly turn the handwheel and see where the loopers cross. The upper looper should come in just behind the scarf of the lower looper without any contact on the forward motion. Otherwise Your needlebar height could be off. Timing a serger is a very precise process and making adjustments could throw it out even further.

Quite possibly the machine is not threaded correctly, the tension setting for that looper is too tight (could be the upper looper tension disk is stuck or dirty causing the thread to hang), or the thread is looped around something like the thread tree.

Replace the needles. Remove all the thread and re-thread from the beginning. Be sure to RAISE the presser foot before threading. Make sure to thread the threads in the correct order.

Serger Troubleshooting For Any Serger Serger Machine Series Ep 4

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The upper/lower looper need realignment, requires a qualified technician to do this.

here is a link for a free manual for the serger, it should have the information in it
http://www.brother-usa.com/VirData/Content/en-US/HAD/Consumer/UsersManual/UM_1034D_ES_178.PDF

Sergers are... well can be a pain. "Lower looper thread keeps breaking." Ok... so Here is what I Would do. Get your magnifying glass out and really get in close with a good light and look for burrs on the looper. Also look for burrs on the throat plate, etc. If you find one use some very fine sand paper and carefully smooth it off.

If that doesn't help or fix it. Take it in to a repair shop and tell them what's going on. you might need it timed too. Good luck

You may have re-threaded in the wrong order. The correct order is upper looper, lower looper, right needle, left needle. So 3,4,2,1 (if numbering left to right)

Most of sergers thread the same way, go to www.singerco.com, - under customer support, or www.brother-usa.com, (support, home sewing &embroidery, pick the 1034d model) these are free or there are videos on youtube.com. I have 5 different sergers, 3 Singers (14sh654, 14u64a, 14j334), 1 Brother (model 1034d), and 1 Babylock Protege. They all pretty much do the same thing. I have learned that you must thread in the order that your manual tells you for the thread to loop right, all of mine, the 3rd spool from the left is the 1st one to thread. Remember, that you have to go behind the looper, using your long tweezers, and hold the thread end slip it behind until it goes into the notch, then bring you thread along the path on the looper and thread through eye. Have patience, I thought I was going to lose my mind also, until I actually took off the throat plate and saw that notch in that looper, then I knew what to look for. Also, make sure that you pull your thread like they show for the tension discs, very important. Some manuals are better than others, but one of those will click with you. I hope that I have helped you because you will love serging once you have it threaded right.

I found that I had to remove the stitch finger to thread the machine properly. Do remember to re-install it before starting to sew. If you are using 3-threads only, then remove and store the stitch finger.
Puzzled that this instruction is not in the threading section of the manual.

I had the same problem with the blue thread- it would sew and inch then pop- mine worked wihtout breaking after I re threaded in this order: green, blue, red then yellow

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