Thanks lachupacabra you are right. I'm talking about this piece in thingiverse: 633070

The screw that we can see at video dropped and I cannot put it again. Now the belt is very tight and I need to be able to make the tension adjustments. If I try another screw, with a big diameter can help me to put it again in the hole (I think). But this piece it's a good suggestion, I'll try it.

If the belt is TIGHT and not LOOSE then there is no problem. You want the belt, ALL belts to be tight. If the adjusting screw is out, then I think you mean the belt is LOOSE.

The screw that we can see at video dropped and I cannot put it again. Now the belt is very tight and I need to be able to make the tension adjustments. If I try another screw, with a big diameter can help me to put it again in the hole (I think). But this piece it's a good suggestion, I'll try it.

but the thing I don't understand is, what's the problem if the belt is tight? Or did you mean loose?

Anyway you can print this: http://www.thingiverse.com/search/page: … ci&sa=
and replace the stock piece.
Use slow speed if you can't fixate the pulley (which holds the belt in tension).

The screw hole quickly wears off, thus failing holding the pulley bracket in place. There are some designs of the above piece, which are using M3 nut instead of bear plastic.

hope it helps

Today I had a belt loose screw, the same we can see at videos support, explaining how to tight it. But I could not put it again. Do you guys have any suggestion? I put at the same place, but when I try to turn it, I cannot find the right hole. I don't know if I'm putting in wrong place or the plastic was gone.

Without this screw, the belt becomes very tight. Thanks!

I have no idea what you are talking about. Can you explain where on the printer you are referring?

Without this screw, the belt becomes very tight. Thanks!