Don't know,on most of them the bolt is a rod that screws in or out to adjust the length,that usually has a flat section on it and a keeper plate on the bottom (top) of the door held in by a screw, you would remove the plate and screw the rod in or out to the correct depth then refit the keeper plate,if it does screw in measure it first and make sure you screw it INWARDS first before you close it or it may not open.Have a look,good luck.
anon
July 2010