How much PTO shaft wobble is acceptable?

[phaser]

I was mowing with the field mower today and noticed a unusual noise when the 3 point was in the raised position, with the PTO shaft still engaged while making a sharp turn. Got it back up to the house and noticed that the raised position was much higher then normal, and subsequently discovered a stop locks(?) had come lose.

So I readjusted it for proper raised height and engaged the PTO shaft to check for noise, which is gone now, and noticed that the shaft isn't running perfectly true at the distal end. This I hadn't noticed before.

I'd guess there's an 1/8 inch wobble.

So how much wobble if any is acceptable or does the shaft need replacing?

Bill

 

[Diydave]

Shaft or shield wobble? I'd say 1/8" might be the borderline, but I'd check to see if the telescoping section moves freely, if that has a bind in it, you can do major damage, to the driveline...

 

[Tooljunkie]

Wobble will take bearings out pretty fast. A bent, off balance shaft will also wear out u joints.

 

[phaser]

It's shaft wobble, not the u joint, but only at the distal end where connects to the field mower. The tractor side runs true.

There is no binding in the telescoping shaft, and the u joints have slight play and otherwise are pretty tight.

So, can this wobble do damage to the gear box on the field mower?

.

 

[Tooljunkie]

If driveshaft yoke is loose on mower shaft, it should be repaired. Maybe a new yoke is all you need. U joints should have no play at all.

 

[Diydave]

It's shaft wobble, not the u joint, but only at the distal end where connects to the field mower. The tractor side runs true.

There is no binding in the telescoping shaft, and the u joints have slight play and otherwise are pretty tight.

So, can this wobble do damage to the gear box on the field mower?

.

Eventually a bent shaft tube which is what I think you have, can cause enough vibration to damage the shaft on the gearbox. What I would do is buy a cheap driveline, from agrisupply.com, and fit it to your tractor and mower. You might have to swap the mower end yoke over onto the new driveline, if you can't find the right spec driveline. Or you could take the back half of the driveline, to a drive shaft shop, and have them make you one up...

 

[phaser]

OK, thanks everyone. I think I'm going to buy a new shaft.

My field mower has a 1/2 inch grade 3 shear bolt which seems way to much for a 13HP PTO shaft.

Seems like something else would break first?

Series 4 seems to be very common as they all have a 1/2 inch shear bolt.

Any suggestions?

Edit: I checked the owners manual for the field mower and it calls for grade 2 shear bolts, and ordered a set of 5 from King Kutter.

.

 

[Diydave]

I busted a 1/2" dia grade 5 pin, on my 4' howse BH, this spring. I pull it with a l2202 that I call the junkubota. It did what it was supposed to do. Problem was I was 35 miles from home, and it was too late in a 14 hr day, to make it worth fixin, in the firld, and I didn't have a spare... I stopped at a local tough sh!t charlie's, on the way home, and bought 4 extras, came home and found 3 more to stock the work truck with. Next time I prolly won't be able to find them...

Whatever your manual says is the kind and grade to buy. At about a dollar a shear bolt, use the right one...