I know this might sound dumb but are you sure it is an L59 and not a 59? I had the same problem as you, not to mention tossing and breaking belts. Between a nice guy on another Allis list and a Woods tech rep, we figured out that my mower is a 59 put on in the early '60s. (Found the id tag on the read mounting tube under layers of old paint and grease) According to the rep, if you have a flat idler, it's a 59. The belt routing is the same as with the L59 except that it crosses over in the rear so everything will turn clockwise (you'll have to change the blades). Also, ignore what the manual says about twisting the belt. With a flat idler, it will find a natural twist. The previous owner had put on the regular lawnmower blades and changed the belt routing. As long as you didn't try to cut anything taller than 6 inches it was fine, but hit a patch of tall grass or weeds and it was all over for the belt. I have copies of the L59 and original 59 manuals, contact me off list if you would like me to send copies.