Megado - While weaving, the tension in the warp changes.

Possible reasons:
1. The brake cable is not mounted properly on the disk. The cable is to be positioned neatly, next to itself on each wrap.
2. The brake pedal is adjusted too high and is released by touching the middle section when the back portion hinges up. During the assembly of the loom the brake pedal was adjusted horizontally. After using it for some time, you will find that the brake pedal has come up a little.
Check the cap nut of the carriage bolt, the hinge point of the pedal, and make sure that the nut is tight. Adjust the brake pedal a little lower, back to a horizontal position:

3. Stand beside the loom and push the pedal down. Slip over the brake disk side one winding of the cable, so that the tension is released. Now let the pedal go and have both hands free for adjustment. Take the cable loop from the threaded hook and twist the hook clockwise for several rotations. Hook on the loop again and push down the pedal so that you can replace the cable onto the disk.

Check the height of the pedal again .