Bad Vibration on RC72R-F30 deck

[Capt.Ron]

I have an F2560E, my deck is RC72R-F30. It's vibrating really bad. It seems to be the PTO, gear box or both.
It's possible to be an out of balance blade or bent spindle but even with the belt off the gearbox still vibrates. I tried removing the shear pin/bolt that attaches the PTO shaft to the gearbox and there still seems to be some vibration. The U-joints don't seem to have any noticeable wear so I can imagine those are bad.
It's so bad it's caused one of the mounting bracket tabs to break off where it bolts to the deck. I welded it and put new bolts all around. Now the tab has broke next to my weld.
Has anyone here experienced this problem and what may I ask did you find?

 

[eserv]

I have an F2560E, my deck is RC72R-F30. It's vibrating really bad. It seems to be the PTO, gear box or both.
It's possible to be an out of balance blade or bent spindle but even with the belt off the gearbox still vibrates. I tried removing the shear pin/bolt that attaches the PTO shaft to the gearbox and there still seems to be some vibration. The U-joints don't seem to have any noticeable wear so I can imagine those are bad.
It's so bad it's caused one of the mounting bracket tabs to break off where it bolts to the deck. I welded it and put new bolts all around. Now the tab has broke next to my weld.
Has anyone here experienced this problem and what may I ask did you find?

Bent driveshaft? Or driveshaft out of phase?

 

[Capt.Ron]

Bent driveshaft? Or driveshaft out of phase?

Can't imagine it's bent but I guess it's possible.
What would "Out of phase" mean?

 

[eserv]

Can't imagine it's bent but I guess it's possible.
What would "Out of phase" mean?

 

[eserv]

You shouldn't be able to assemble the drive shaft "out of phase" but I have seen quite a few times the locating tab either rusted or ground away so they will.

 

[Capt.Ron]

That's interesting. Guess I need to check that but if I remember right, this one can only go together one way. It has like a weld on one spline that lines up to a bigger notch on the yolk. I did have them apart to clean and lube when I first noticed this vibration.
I guess it's possible that it could be twisted. I do sometimes mulch small limbs with it! LOL!!

 

[Capt.Ron]

Not expecting it to be out of phase but I'll get to that when it cools down a bit. Too darn hot right now!
I did go look and give it a bit of a wiggle. There is slack between the PTO and the gearbox shaft.
It have always been that way. Or the vibration could have caused it to have that slack. There is a threaded hole for a set screw but I've had it for at least 12 years and I don't remember a set screw being there.
I also don't remember seeing a set screw in any parts diagram.

 

[Capt.Ron]

I guess I need to pull the shaft and put it on a bench but attempting to check the incline while on the mower I got 1.3 to 5.7. Not sure how much I trust using this app. The edge of my phone is straight but I just don't know how trustworthy it is.

 

[Dave_eng]

eserv is the one to follow.

My only suggestion is to remove the deck V belt and see if the vibration changes.

Dave

 

[NCL4701]

When I took over use and maintenance of my Dad’s rotary cutter it vibrated worse than a vibratory packer. He hadn’t used it for many years. One of his friends had been using it. PTO shaft had long ago lost any key if it ever had one and would go together any of four different ways; two in phase, two out. It was out of phase. Putting it back in phase and experimenting to see which of the two options vibrated less removed most of the vibration. A bit of additional work with an angle grinder on the long neglected blades removed the rest of the vibration.

Not sure how yours would have gotten out of phase but it is a real problem if it is out.

 

[Capt.Ron]

eserv is the one to follow.

My only suggestion is to remove the deck V belt and see if the vibration changes.

Dave

Yep, done that. Still vibrates. Also vibrates with the shear bolt removed from the gearbox/PTO shaft.
Something new that I noticed this evening after making this post.
The ujoint closest to the tractor now seems a little sloppy.
I had that thing off a couple of weeks ago and it seemed pretty solid.
The question for me now, did the vibration cause the ujoint issue or was it the Ujoint all along and I just couldn't tell? Ugh!

 

[number two]

I have found that u-joints get a little tight and squeaky as one of the ends start to fail.
It usually results in rust streaks coming from bad end.
These are the symptoms I look for when trouble-shooting u-joint problems.
Good Luck !

 

[CGMKCM]

My ZD323 had really bad deck vibration. Vibration was worse when deck was fully raised vs. mowing height. Gear box bearings were shot and belt tensioner bearing was also shot I ended up replacing spindle bearings also. My deck had 1400 hours of mowing in sandy conditions. What does your deck drive belt look like? I went through 2 belts in 50 hours prior to repairs being made.

 

[Capt.Ron]

I have found that u-joints get a little tight and squeaky as one of the ends start to fail.
It usually results in rust streaks coming from bad end.
These are the symptoms I look for when trouble-shooting u-joint problems.
Good Luck !

So, anyone got a good supplier for ujoints? I looked at one place, (messicks or Jacks small engines) they wanted 85 bucks just for the joint. Caps were extra!! Unless I read that wrong.

 

[Capt.Ron]

I noticed some slop in both yokes. The one at the tractor PTO and the one at the mower deck. I don't usually throw parts at a problem but I ordered new yokes and ujoints for both ends from Messicks.
They must be having a hard time finding them. It's been too weeks and I've received no notice of a delivery order being created. Hopefully they'll come through soon.
If that doesn't fix it, I'll open the gearbox to see what I find.

 

[number two]

So, anyone got a good supplier for ujoints? I looked at one place, (messicks or Jacks small engines) they wanted 85 bucks just for the joint. Caps were extra!! Unless I read that wrong.

Spicer seems to have the good stuff!.
OE own many cars and trucks.

 

[Capt.Ron]

Bad news from Messicks. All of the parts for my PTO shaft are discontinued from Kubota.
One thought, the yoke at the gear box seems to have the most slop, if I could find the ujoints based on specs as opposed to mower and deck model maybe I can have the yoke bored and press a sleeve in so it will again be tight on the gearbox shaft.
Also, the gear box placement seems to ask for problems. It's offset from the shaft coming out of the tractor. I'm wondering if I were to rotate the gearbox a few degrees to at least make the gearbox shaft and the PTO shaft line up, would that help in reducing potential vibration once I get the rest repaired?

 

[MOOTS]

F3680 at work. Box is offset also.