Have a bush hog brand SQ600 purchased new in 2007. When new the blades would fold up if needed and then unfurl to correct position. Last few years this has been gradually worst where they will not straighten out if they hit a limb or other object. Seems like it is getting grass and debris between the top of blades and the stump jumper and causing to bind up. Yesterday was the worst time I have had. Accidentally ran over about a 4" limb and caused the blades to fold up but would not come back straight. Has to raise mower up all the way and put jack stand under back of mower. Used 2.5 pound hand sledge to get them back straight. One of them required very little force but the other was very difficult to straighten out. plugged with grass and binding badly. When I change blades I always put grease between blades and stump jumper and they swing freely then, then squirt oil on them a few times till the next time I swap blades. So, I guess my question is What are you guys doing to keep your blades free swinging. Almost 100% sure that it is grass getting wedged on top of blades but do not know how to keep it out from that area.