How to replace a broken 925D lower looper threader

Have you tried to use the wire looper threaded to get the thread through the looper?
I have often used wooly nylon thread with the looper threader(above) (several thicknesses) using a clear dissolve The to clean out the tubes where the thread flows through the looper.
Apart from this you may require professional assistance by a qualified Babylock Technician

hi Goldie.
you have not said what make or model you have,so would not know what manual you would be after,
but his link might help you out on the looper.
How to get to lower looper to thread Google Search

If the upper looper is moving normally but lower looper is not moving, then you've got a broken part internally and it needs to be taken to a serviceman.

Does your machine have a threading diagram inside the front drop down cover over the loopers? Many machines have a diagram here which includes red dots for oiling points.

Usually a couple of spots where the loopers move through/over another metal part.

Important to firstly brush out the whole area underneath the needle plate, around the blade, and the loopers and inside the case area completely, removing the lint with a brush and cleaning it into your bin. The lint waste will absorb any oil so clean it out with each use.

Then apply the oil to the looper points.

You should also rub a little bit onto the blades, you usually can lift the upper blade/swing it away from the lower so do this and clean them both with a cloth that has a dab of oil on it, then lower it back into position.

Then serge for a bit on waste just to make sure its not too oily on the blade for your good fabric.

Hope this assists you, I'm guessing you don't have the manual but always good to obtain if you can - you can buy one here. http://www.sewingpartsonline.com/instruction-manual-brother-925D.aspx

Apparently either you have no needle threaded to lock the stitch or both loopers aren't correctly threaded. You must thread your UPPER looper first (don't know what color yours is), LOWER looper next, RIGHT needle next and last the LEFT needle if you are using the 4 thread overlock stitch. It sounds like you are having trouble with your lower looper. Look for the lower looper threader to help you thread it. Your manual should show you a picture.

Do you know the looper threader broken can be repair by yourself? I suggest you to order the following product:
Sewing Machine Repair Guide
It's a professional repair guide written by an expert. Besides PfaFF sewing machine, you can learn how to repair other brands of sewing machine as well. The author claims that you can earn money after you had learned the repair skills!
Good luck.

my brother lock 925d serger sewing machines threads do not overlock sitch

check to make sure it is not wraping around the upper looper. just stitch without the material and you will see it. but then you must rethread the upper looper and the lower looper again in the right order. hope this helps

Probably your looper timing is off. This is common, and just a necessary evil of sergers. Their tolerances are tight.
The operation of creating a serger stitch is a succession of thread grabing and delivering. One looper grabs a thread and delivers it to the needle and so on.
To check this, turn your handwheel slowly and check to see that the upper looper is meeting the lower looper by passing very close to the indented part at the back of the lower looper (indented part is called the scarf, this is where the looper threads form a lock) If not, it's the looper timing. If they seem to meet properly then check your needle. Is your needle up into the needle clamp all the way? Try a new needle. Even a slight bend to the needle will not allow the loopers to meet and grab or deliver thread. You might check the tensions. Thread has to have some resistance in order for the loopers to do their job,

If your looper timing is off, find a sewing repair person to retime the serger. Don't try it yourself or put this repair off. If the loopers go further out of timing, they might hit something and replacement can be costly.