Loose blades on RC72 deck

[PLR]

I have a F 3060 with an RC72-F30 deck. Had it for a long time and every couple of years we have to replace the cupped washers on one or more of the blades. For whatever reason, this year one blade keeps going loose. The bolt stays tight but the washers allow the blade to turn freely, even with new washers, correctly installed. I took the spindle out and both bearing and seal seem good. A tiny bit of bearing play but pretty tight and no bearing noise when spun. Blade bolt is original and nothing looks excessively worn. Any ideas/suggestions?

 

[freewheel3]

I have a F 3060 with an RC72-F30 deck. Had it for a long time and every couple of years we have to replace the cupped washers on one or more of the blades. For whatever reason, this year one blade keeps going loose. The bolt stays tight but the washers allow the blade to turn freely, even with new washers, correctly installed. I took the spindle out and both bearing and seal seem good. A tiny bit of bearing play but pretty tight and no bearing noise when spun. Blade bolt is original and nothing looks excessively worn. Any ideas/suggestions?

Does it feel like the bolt is bottoming out in the spindle? If so, maybe there is some debris packed into the bottom of the hole, stick a pick or screwdriver in there and see. Or possibly the bolt is stretched a bit and bottoms out before there is enough tension on the cupped washers. A quick fix would be to add another cupped washer.

 

[whitetiger]

I have a F 3060 with an RC72-F30 deck. Had it for a long time and every couple of years we have to replace the cupped washers on one or more of the blades. For whatever reason, this year one blade keeps going loose. The bolt stays tight but the washers allow the blade to turn freely, even with new washers, correctly installed. I took the spindle out and both bearing and seal seem good. A tiny bit of bearing play but pretty tight and no bearing noise when spun. Blade bolt is original and nothing looks excessively worn. Any ideas/suggestions?

With the blade off, does the boss or hub slide all the way onto the shaft spline freely? Check to see if the outside of the boss is worn or the hole in the blade is wallowed out.

 

[Dave_eng]

Whitetiger is pointing you in the right direction!

The bolt, hub connector and blade have all worn a bit and the blade is no longer being centered on the spindle.

When things are rotating, being not perfectly centered results in movement between all these parts and the blade gets loose.

Do not just replace the most obviously worn parts but rather replace the blade and the other centering parts.

Dave

 

[PLR]

Great advice! Thanks for the leads. I will follow up and revert.

 

[skohler]

Having this exact same issue with one blade on my ZD. I went out and bought new blades and cup washers and just replaced them all. After mowing some heavier grass I noticed the blade near the discharge opening was not cutting very well and sure enough it was loose again.

I could not tighten it up enough so added another old cup washer and was able to make it work. Was just about to post when I saw this thread- will pick up another bolt and the other part that holds the blade (no idea what it is called).

Thanks for the original post and another thanks to the folks who replied.

 

[whitetiger]

Having this exact same issue with one blade on my ZD. I went out and bought new blades and cup washers and just replaced them all. After mowing some heavier grass I noticed the blade near the discharge opening was not cutting very well and sure enough it was loose again.

I could not tighten it up enough so added another old cup washer and was able to make it work. Was just about to post when I saw this thread- will pick up another bolt and the other part that holds the blade (no idea what it is called).

Thanks for the original post and another thanks to the folks who replied.

Kubota calls it a "Boss"