That would be the tpa cross threading, to tyake it out the is a bolt on the lever body just as the lever dissapears under, unsrew that and the lever will fall out then you will need this http://www.tartybikes.co.uk/product.php?id=10023 and this if you dont want it to thread again http://www.tartybikes.co.uk/product.php?id=2066 other wise you will go through so many plastic tpas