You should remove them, clean them right off and weigh them after sharpening. get their weights as close as possible, at least in pairs which should then be fitted opposite each other to reduce vibration. Poorly balanced blades will wear the bearings out in the cutter deck.
Jules
July 2010
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix lawn mowers.