The sewing clamp and the needle guide fell off while I was sewing. I can't get it back on. Need instruction.

Try a different brand of needle . Cheap Chinese are made to small.

just adjust to needle in fix to strait in needle clamp hole it operate to needle strait to hole so needle do nt break but needle is best buy qualtity

the needle clamp may need to be replaced,, a sewing machine shop can tell you for sure

try youtube for a video

I've done this, and it's a pain, but can be done. Let me also tell you that quite a few users have broken theirs and just used the machine without it, but others said that they had to replace theirs. First of all, the wire guide is held UNDERNEATH the needle clamp, and what you have to do is insert them back in one piece. That is, remove the clamp, insert the end of the guide, then push them together on the shaft as one unit. The end of the thread guide sticks up over the top of the clamp in the back. There is a very tiny screw there that's supposed to hold it, but most machines are produced without the end going underneath that screw--they just let the needle clamp hold it. That screw is VERY tiny and VERY difficult to access, and will come out completely after only a few turns. Worse yet, it serves as a "stop" for the end of your needle, so if you lose it, you'll have to use something like a toothpick to "stop" the end of the needle until you can replace it. ASK ME HOW I KNOW! It is easier to deal with if you put the machine on its side when you do this.

This was happening to me also - you have to tighten a different screw than the one that holds the needle in.

http://www.sewingpartsonline.com/needle-clamp-screw-brother-ls-2125-sewing-machine.aspx

My husband thought the screw was missing - it is actually a plastic screw with a hole in it for a tiny allen wrench.

You can see it in this picture also

http://www.sewingpartsonline.com/needle-clamp-babylock-brother-xz0001051.aspx

If you look at the photo of the screw I attached, you can zoom in and see it has a hexagonal hole.

It is above the flat head needle clamp screw (the one that holds the needle in)

It is REALLY annoying that this screw is mentioned nowhere in the manual, and the hex allen wrench is not included with the machine.

Kind of an important little detail, considering it holds the needle assembly together... you'd think that they would have told you about it.

needs a new needle clamp screw & possibly the needle clamp too

try sewingpartsonline.com

when you put the needle in the needle clamp holder the flat side of the needle goes toward the back of the the machine when you tighten the needle clamp screw make sure it's holding the needle,,make sure you can't pull the needle back out of the clamp,, if you can something is wrong with the needle clamp or the screw

I have an XL6452 and the same problem. I figured out that you can use a tiny screw driver (or an allen wrench might work). I tried using the screw that tightens the needle but it didn't seem to work. The screw looks like it just a hole. It took a lot of turns to get it loose enough so you can put it on. You will see it come out.
Once you get it on you can tighten it.

That can be tricky. Some thread guides and needle clamps have to be assembled and then slid up into place with the needle screw holding it together. Some have a set screw to hold it.