59 Cub Lo Boy Flail Mower Vibration

[John Ciarlette]

I have a 59 Cub Lo Boy w/MOTT LB FH flail mower. The drive shaft attaches to the pto but is loose. There is a cotter pin that holds the drive shaft on the pto shaft but not all the way. I have tightened up the clamp bolt as tight as I can but it still is loose and much vibration. I noticed if I take pin out and push drive shaft further onto pto shaft, there is less vibration but will work itself off because the pin holes do not line up at that point. When the pin is in, the u joint of the drive shaft is only partially on the pto shaft. I am thinking of drilling a new hole in u joint so the u joint is further on the shaft.

Is this the way to go or does someone have a different solution?

[SamsFarm]

I have no experience with a fast hitch Mott (yet), but it sounds like your pto shaft is worn or the internal splined area of your pto shaft is worn, or maybe a little combination of both!

Another thing is the phase of the two u-joints on the shaft.

If your pto shaft is a true square, then you might try pulling the shaft apart and slide it back together 90 degrees from where it was.

On another note, how is your crosses in the u-joints themselves?

Smooth and firm?

Tight?

Gritty?

Or sloppy?

[John *.?-!.* cub owner]

Like Samsfarms, I have no experience with a fast hitch flail, but do have experience with pto equipment. It sounds as if either the pto shaft or the mower shaft may be worn to the point of needing replaced. Another possibility is a universal joint, but I am stronly leaning to wards the splines being worn.

[mva1958]

I had the same issue, the splines on the yoke were worn and sloppy. If you don't replace the yoke you run the risk of ruining the PTO shaft splines as well.

I got a Weasler series 6 yoke, part number 105-0610. It's a spring-lock type connector, so you'll have to remove the spring and collar and drill holes for the cotter pin.

The yoke on the drive shaft end of my PTO connector was worn badly by the years of vibration that the PO had put up with, so I had to replace mine, but your's may be okay. If you have to replace it, get a square shaft with a Weasler series 6 yoke attached from Tractor Supply or one of the mail order houses. I think I got mine from Blain's Farm and Fleet. Don't forget to get a new cross and bearing kit. Good luck and if you go this route please post some pics. I wish I had documented my project but I was too hot to get it back in operation.

[tst]

also flail will vibrate if you have broken or missing blades then it ruins the bearings if not dealt with

[John Ciarlette]

The pto shaft is rectangular. The yokes are tight. I am going to replace one missing blade and drill another hole higher on the yoke so the spline shaft fits all the way in yoke. I'll update with progress. Thanks for all the info.

[Buzzard Wing]

I don't believe that drilling a new hole in the PTO shaft is a good idea. There should be a bolt AND the cotter pin on that collar.

I have to think for a bit, but my thoughts are: 1) the PTO is out of phase; both 'knuckles' of the U-joints should face the same (as I recall) 2) the PTO shaft is NOT square, it is a slight rectangle and fits easily when it is correct. (see also #1) 3) bad bearing, either PTO (Replace with a sealed one (6205 2RS??) no grease again, CASE IH ones are junk last I saw) or the U joints. 4) bad cutter shaft bearing(s) 5) missing knives, including their mounts (I had one that was missing several of the mounts, Flailmaster is where I recall getting them) 6) bad bearing in the gear box (it is a Cub right angle pulley) Change the gear oil in it while you are at it. Water can get past the front seal too, pull the level plug on the side first to see if it is overfilled. 6) Replace the Cub's PTO shaft.

Do you have a copy of the Mott manual? I can email one. The mower should swing some from side to side and have a 'dropped' bar on the fast hitch.

[John Ciarlette]

Thank you for replying. Sorry it took me this long to reply back. I would appreciate it if you could email a copy of the Mott manual.

Thank you very much