frustrated...brush mowing breakdowns

WI Dan · Jun 15, 2023

I've busted two rotary mower PTO shafts in the last week. Keep hitting stumps or rocks. I'm frustrated!!!!
Why isn't the shear bolt breaking? I have it tightened on the yoke...
How do I keep the mower deck from going up and down with the back of the tractor? It's a three-point mount.

The rocks are hiding in the weeds. I can't see them. The ground is very uneven, lumpy. I guess I need to back off and be less optimistic about the size trees it can handle.

Ugh...I'm really getting worried, the weeds are growing and I want them cut so the grass can come in instead!

Patsdeere · Jun 15, 2023

Ug is right. To break two shafts, I can't
imagine the abuse the mower took. You
could use a chain instead of a top link,
that would give you first when the tractor
nose goes up, but would still limit the
mower.

Sometimes things are just too rough to
bush hog...

jddrawbar · Jun 15, 2023

You could be trying to mow too low. Also, I would recommend going to a slip clutch instead
of a shear pin.

37 chief · Jun 15, 2023

Rocks are a killer all right. I busted a gear box on my woods mower. I brazed it back together. I use mostly my flail mower now. In a field
where there is a possibility of rocks. I keep my hand on the lift lever. Stan

WI Dan · Jun 15, 2023

This mowing is new to me. I recently started caretaking a farm. The equipment came with it. Everyone says: "it worked fine last year"
Nevermind the PTO shaft was booger-welded crooked and twisted...

I'm trying to learn the land. Some place are very smooth, others are lumpy. Rocks everywhere! I've never experienced that before. Big ones, little ones, some as big as the tractor. No gravel to find, it's all heavy clay soil.

I guess breakdowns are my cost of education.

gtgmd · Jun 15, 2023

I put my FEL down , tilted back and low enough to act as a bumper or jumper to warn of things unssen

rrman61 · Jun 15, 2023

I would drag something wide and heavy in there first
to show the obstacles.a piece of small diameter but
heavy pipe or a railroad rail or even a log.something
that will smash the brush down flat .if what your
dragging is heavy it will bow over any trees small
enough for your cutter.anything else is too big.it will
not be pretty but will save your cutter

BarnyardEngineering · Jun 15, 2023

What grade is the shear pin? It should be a soft bolt, Grade 2 (i.e. no markings on the head). If it has 3 or 6 lines on the head it is too hard and that's why it's breaking shafts.

leroy in ne · Jun 15, 2023

Addition to grade of shear bolt. Pull the bolt and make sure collar will slip on shaft and is not rusted tight.

leroy in ne · Jun 15, 2023

Additional thought: Is equipment matched? In other words a mower designed for a 20 or 30 horse tractor being run by a 125 horse tractor may have breakdowns by being over
powered.

rrlund · Jun 15, 2023

Cut higher until you find all the rocks and stumps.

13fx · Jun 15, 2023

Problem with most of Wisconsin is that it's
glacial till. Every dang hill was left there
from a melt hole in a glacier so you get
rocks, and rocks and more dang rocks. Flat
areas tend to be clay. There are some sandy
area throughout the state, but mostly glacial
till.

Jim.ME · Jun 15, 2023

In addition to the suggestions so far. Do you know the brand and model of the mower? And what is the tractor you are using? Post a couple picture of how the mower is hooked up to the 3 point, including the top link connection. Post some pictures of the PTO shaft. Sometimes things show up in pictures that might be picked up by those looking at them that we look right past.

Liquid_wrench · Jun 15, 2023

I put my FEL down , tilted back and low enough to act as a bumper or jumper to warn of things unseen.

That's a good idea.

Janicholson · Jun 15, 2023

If your mower has one or more rear wheels, the top link on your 3 pt hitch should be a chain or tubular free to collapse shorter. You might consider raising the mower to 8 inches or so. Another option is to use a herbicide and kill it all off. Start new when you can do rock picking (or chainsaw down the 2 inch brush). Jim

Goose · Jun 15, 2023

I have a 6' unit identical to that.

I don't understand why the shear bolts don't break. I break them all the time when I hit something. However, I never tighten them, just leave them a tad loose.

caterpillar guy · Jun 15, 2023

All good things to check. Sounds like you need one of those grinder deals that goes on the front of a skidsteer they look like they ground everything to mulch and leave the ground clean as you go. Will grind off pretty big trees with them along with the weeds and grass this first time over. IF you plan to work this ground afterwards you better get the stumps out or it will be a second learning experience all over again then.

sotxbill · Jun 15, 2023

I can break the grade 3 bolts just on hitting 5 or 6 fireant mounds in august. So I suspect your using harden black or even harder gold bolts if they are not breaking. When we shred mesquite pastures we start out with a minimum of a bag of 10 each 1/2 bolts, 2 3/4 long with lock washers and nuts with two crescent wrenches on each tractor. Depending on the sign of the moon, almanac and stars, we may break 1 bolt in 6 days or 15 bolts in one day. We have moved up to black bolts with 3 marks and have satisfactory results as they will allow about 10 fire ant mounts or gopher mounds to go through, and still break on the bigger stumps. However by moving up to the 250 hp gear boxes with 8 inch pto clutches... means now we break a blade or two each year and twist the pto shafts pretty badly each year. The Hardy 7 foot right of way shredders are pretty hard to beat, but you have to add about 300lb to the front of the 6640 to keep the front wheels on the ground.

Traditional Farmer · Jun 15, 2023

You are about 4 months too late,need to cut that type field in Feb or March the first time and pick up the rock and mark the stumps.Abused equipment breaks down.

Jim.ME · Jun 15, 2023

Black bolts are also called plain finish and doesn't affect strength rating, 3 marks on the head is the common marking for a grade 5 bolt, not grade 3.

frustrated...brush mowing breakdowns

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