Victory Flail Mower - breaking shear bolts constantly

[camshawn]

Our JD rotary deck uses a metric shear bolt. Used an equivalent sized standard bolt, lasted seconds. The slightly smaller diameter of the standard bolt allowed just enough movement to shear the bolt when the clutch grabbed. Just another thing to check.

 

[bmaverick]

Our JD rotary deck uses a metric shear bolt. Used an equivalent sized standard bolt, lasted seconds. The slightly smaller diameter of the standard bolt allowed just enough movement to shear the bolt when the clutch grabbed. Just another thing to check.

Since my shear bolt problem was also on a JD261 finish mower 3-point rear deck, I can tell you how I fixed the issue.

I quit using a shear bolt. Instead, I went with a Grade 5 shoulder bolt. The shoulder filled the thru holes perfectly vs a shear bolt. And the threads came out just slightly after the last hole for the nylock. Since then, this is all I use now on my PTO implements. Nothing with the tractor nor the implements has ever broken otherwise in the past 8 years.

I have a KK brush mower with stump jumper. Even under the harsh mowing and field stumps, I've only broke 3 of those Grade 5 shoulder bolts and nylock.

The nylock is very important. I would be working and the shear bolt nut would back off no matter how much I would impact them on. Well, that was another reason why they broke so much. The cost of a nylock is pennies more. And I don't ever need to torque them down. Only snug, not impacted nor torqued down. It's a self learned trick I discovered.

 

[leonz]

Hi folks, I’m new to tractors and flail mowers. Last year I purchased the Victory Flail Mower (model: FMHDX-94 Extra Wide Heavy Duty Flail Mower). I continue to have issues breaking PTO shear bolts. As soon as I engage the PTO - the shear bolt snaps. I have a CAT II tractor (Allis Chalmers 7010 - 100 HP). Sometimes I can engage the PTO and get 10-20 feet then the shear bolt shears. I’ve replaced about 8-10 bolts so far trying to make adjustments to the flail mower position - nothing seems to work. I’m using the bolts recommended by Victory (M8 10.9 I believe). The flail mower skids sit on the ground - should they be raised? I also heard that I should eliminate the shear bolt from the PTO - the belts on the flail mower will protect the mower’s gearbox. Any thoughts appreciated.

OK, lets start at the beginning.

The 2 lower link mounting pins need to be placed in the lowest mounting holes.



The flail mower must be adjusted to be level and not pitched forward or backward.
You adjust the front to back level of the flail mower by placing a small bubble level
on the top of the gear box cover with the long length facing you as you look at the side of the
flail mower.

You use the top link to adjust the flail mower level from front to back using the bubble level.

The rear roller is what sets the cutting height of the flail mowers side slicer knives, scoop knives
or hammer knives NOTHING ELSE.

With your flail mower your skids carry the rear roller and you have to lower the skids.
You need to lower the skids first so the bolts holding the skids are holding the skids in the lowest position.

After you have readjusted the skids and tightened the bolts you can level the flail mower from front to back.

Your tractor should have a locking knob to keep the lower links from dropping causing the mower to pitch forward.


NOW I need to know more about your PTO shaft; You may have a PTO shaft that is not a high horsepower Erocardan PTO shaft and it may not have heavy enough shear pins.

 

[camshawn]

I did something similar, turned a long 12 mm bolt to just fit the hole and cut a new thread for a 1/2 nyloc so the shear bolt contacted the full thickness of the outer yoke.

 

[Williy]

Have you checked to see if the blades are free wheelin?
It only takes a small piece of wire or string to bind the blades

willin

 

[K5lwq]

OK, lets start at the beginning.

The 2 lower link mounting pins need to be placed in the lowest mounting holes.



The flail mower must be adjusted to be level and not pitched forward or backward.
You adjust the front to back level of the flail mower by placing a small bubble level
on the top of the gear box cover with the long length facing you as you look at the side of the
flail mower.

You use the top link to adjust the flail mower level from front to back using the bubble level.

The rear roller is what sets the cutting height of the flail mowers side slicer knives, scoop knives
or hammer knives NOTHING ELSE.

With your flail mower your skids carry the rear roller and you have to lower the skids.
You need to lower the skids first so the bolts holding the skids are holding the skids in the lowest position.

After you have readjusted the skids and tightened the bolts you can level the flail mower from front to back.

Your tractor should have a locking knob to keep the lower links from dropping causing the mower to pitch forward.


NOW I need to know more about your PTO shaft; You may have a PTO shaft that is not a high horsepower Erocardan PTO shaft and it may not have heavy enough shear pins.

Is the leveling procedure the same if the mower top link mount does not have a fixed hole but a slot? I would think setting the level with the 3pt lever and setting the stop at the level point would be correct. Then adjust the top link so the pin on the mower is in the middle to allow the mower to follow the ground better.

I ask because that is how I run my Victory flail and do not have any issues. But maybe I am doing it wrong.

Click link below for a picture.

https://etractorimplements.com/wp-content/uploads/2023/07/IMG_9681.webp

 

[workinonit]

OK, lets start at the beginning.

The 2 lower link mounting pins need to be placed in the lowest mounting holes.



The flail mower must be adjusted to be level and not pitched forward or backward.
You adjust the front to back level of the flail mower by placing a small bubble level
on the top of the gear box cover with the long length facing you as you look at the side of the
flail mower.

You use the top link to adjust the flail mower level from front to back using the bubble level.

The rear roller is what sets the cutting height of the flail mowers side slicer knives, scoop knives
or hammer knives NOTHING ELSE.

With your flail mower your skids carry the rear roller and you have to lower the skids.
You need to lower the skids first so the bolts holding the skids are holding the skids in the lowest position.

After you have readjusted the skids and tightened the bolts you can level the flail mower from front to back.

Your tractor should have a locking knob to keep the lower links from dropping causing the mower to pitch forward.


NOW I need to know more about your PTO shaft; You may have a PTO shaft that is not a high horsepower Erocardan PTO shaft and it may not have heavy enough shear pins.

My Maschio is designed to float on the lift arms and toplink.

 

[leonz]

So much of this is also based on the current location of the lower links on the splines
and how far they travel to the ground as the three point hitch was designed for ground
engaging implements like the moldboard plow.

The tail wheel of an in furrow plow aids in the control of the plows depth with the top link
of the three point hitch which controls the suck of the plow shoe/point.

If flail mowers had 4 caster wheels set with 2 in the front and 2 in the rear they would
have many fewer problems with mower height adjustments and control.

 

[leonz]

Is the leveling procedure the same if the mower top link mount does not have a fixed hole but a slot? I would think setting the level with the 3pt lever and setting the stop at the level point would be correct. Then adjust the top link so the pin on the mower is in the middle to allow the mower to follow the ground better.

I ask because that is how I run my Victory flail and do not have any issues. But maybe I am doing it wrong.

Click link below for a picture.

https://etractorimplements.com/wp-content/uploads/2023/07/IMG_9681.webp

As long as the mower is adjusted on a level surface it will suffice.
I have no idea why these slotted top links are used unless it is simply
to make attachment to the tractors top link easier.

 

[TerryR]

I have no idea why these slotted top links are used unless it is simply
to make attachment to the tractors top link easier.

The slotted top link is essential to allow the mower to follow the contour as you run over hills and dips.

I set the height of the front of the mower by adjusting the height of the lower links, then adjust the top link so the pin is in the middle of the slot so the mower and move as needed as I drive over the hills and dips.