The madrell shaft is available as a spare part, and will need to be replaced. Undo the top pulley nut and tap the shaft down and out, the new shaft comes with the bottom bearing, the bearing will be a snug fit in the housing, you should also replace the blade and a new bolt, when you order the blade make sure it is the high lift blade if you are bagging the grass, or mulch blade if you are not. If you need part no.s let me know if this machine has a 36" deck or the later 97cm deck.
Husqvarna man
May 2010