kioti dk45 hydraulic is making bumping noises

[robert tiller]

when i raise the box blade up it makes bumping noises and you can let it down some and it will quit. also if the draft is all the way up you cant let blade down with position lever. Any help or a phone call would be appreciated .tractor has 369 hours on it.dealer 100 miles away says it can be adjusted with a screw under seat

 

[yippicoyote]

Mine does the same thing...