Brush hog sheared multiple bolts

[Chilei]

I am relatively new to small tractors, I have a3n L3130 tractor and a land pride rcr 1860 brush hog. I've sheared a couple of bolts (one because I didn't realize I had to engage the pto at a low rpm), but today I sheared the shear bolt and the four bolts which secure the safety shroud.

I need to know why this happened and how to get the rest of the bolt out of the transmission. I appreciate anything anyone can offer. I know the pto can't be engaged with power and have been engaging it at idle. It's very frustrating and I'm open to any suggestions.

 

[Chilei]

I am relatively new to small tractors, I have a3n L3130 tractor and a land pride rcr 1860 brush hog. I've sheared a couple of bolts (one because I didn't realize I had to engage the pto at a low rpm), but today I sheared the shear bolt and the four bolts which secure the safety shroud.

I need to know why this happened and how to get the rest of the bolt out of the transmission. I appreciate anything anyone can offer. I know the pto can't be engaged with power and have been engaging it at idle. It's very frustrating and I'm open to any suggestions.

BTW. I mowed without problem for an hour or so yesterday and this happened as I started today.

 

[William1]

Gear box mounting bolts may of been too low a grade or loose, letting the box bang about. Those washers should not be cupped like that (signs of over tightening) either, All points to assembly errors.
You'll need to get the gear box off and a left handed drill bit to remove the bolt shanks. If you are not up to the task of removing the broken bolts, a decent machine shop can do it easily. Better to suck it up and pay the man than make a small problem worse by over zealous efforts.

 

[Russell King]

Okay I am not sure I understand what “safety shroud“ you are talking about so please clarify that. It looks like the sheared bolts are in the right angle gear box on the mower so I am going to assume that was a mounting face for the safety shroud you are talking about.

All that being said…

Is the PTO shaft between the tractor and mower cut to the correct length? Read online on how to know if that is correct.

Is the shear bolt going through the input shaft on the gearbox after passing through the yoke on the PTO shaft? If so, there is probably (supposed to be) a circlip on the end of the input shaft to keep the PTO shaft on the input shaft of the gearbox, else it could come off and become a slinging around “shaft of death” that is headed towards the tractor and your head. I am assuming that circlip is missing, the shear pin sheared, the PTO shaft came loose and hit your safety shield. I would think that would have made quite the racket but you don’t mention that so I may be wrong.

As to the four bolts, you will need to get a center punch, a small drill bit and try a left hand drill bit (larger size) or an easy out. As @William1 states, don’t be fooled by the name “easy out” because they are usually not easy to get out. Read and watch videos on “twisted off bolt removal” and you will get a few different possible solutions (or disasters). The main problem is that you start off with the center punch NOT on the center of the remaining bolt and that can lead to drilling into the case of the gear box eventually (or cracking it somehow). There are new gearboxes that you can replace yours with IF things go sideways on you. (But the suggestion to get an experienced person involved is good advice.)

 

[#40Fan]

Isn't that safety shroud/guard plastic?

 

[Chilei]

Isn't that safety shroud/guard plastic?

Yes, it's plastic.

 

[airbiscuit]

Better pictures showing where the shear bolt goes through the right angle gear box drive would help. Also a picture of the PTO shroud/guard. I don't know how a plastic guard shears bolts.

Usually,when a shear bolt breaks at the gear box, you just drive the broken part with a bolt (you may have to align the bolt holes)

 

[#40Fan]

Yes, it's plastic.

Pull the PTO shaft and cover away from the gear box and take some pics. Something inside the shield had to have taken out those four bolts.

 

[Chilei]

Okay I am not sure I understand what “safety shroud“ you are talking about so please clarify that. It looks like the sheared bolts are in the right angle gear box on the mower so I am going to assume that was a mounting face for the safety shroud you are talking about.

All that being said…

Is the PTO shaft between the tractor and mower cut to the correct length? Read online on how to know if that is correct.

Is the shear bolt going through the input shaft on the gearbox after passing through the yoke on the PTO shaft? If so, there is probably (supposed to be) a circlip on the end of the input shaft to keep the PTO shaft on the input shaft of the gearbox, else it could come off and become a slinging around “shaft of death” that is headed towards the tractor and your head. I am assuming that circlip is missing, the shear pin sheared, the PTO shaft came loose and hit your safety shield. I would think that would have made quite the racket but you don’t mention that so I may be wrong.

As to the four bolts, you will need to get a center punch, a small drill bit and try a left hand drill bit (larger size) or an easy out. As @William1 states, don’t be fooled by the name “easy out” because they are usually not easy to get out. Read and watch videos on “twisted off bolt removal” and you will get a few different possible solutions (or disasters). The main problem is that you start off with the center punch NOT on the center of the remaining bolt and that can lead to drilling into the case of the gear box eventually (or cracking it somehow). There are new gearboxes that you can replace yours with IF things go sideways on you. (But the suggestion to get an experienced person involved is good advice.)

Yes, those were from there 90 degree. I have a reverse bit to try. The bolts are grade 2 from home depot as specified. How often do most replace them? The brush hog works great other than these shear bolts. Maybe the grade 2 bolts are even less quality?

 

[airbiscuit]

Many of us on this forum use rough cut mowers with shear pins. If they break, it is usually because the PTO is engaged harshly (high RPMs, or abrupt clutch), or the blades hit a rock, stump or other object.

 

[Russell King]

Yes, those were from there 90 degree. I have a reverse bit to try. The bolts are grade 2 from home depot as specified. How often do most replace them? The brush hog works great other than these shear bolts. Maybe the grade 2 bolts are even less quality?

I have never needed to replace a shear bolt on my cutter. But that is because I only mow about 4 acres and only a couple of times per year. It is the same 4 acres and has no rocks sticking up on it and it has been mowed for years. And I mow pretty high at about 4 to 10 inches. But I have also used it to cut up limbs that are up to 3-4 inch diameter.

I use grade 2 bolts and put a stack of washers on both sides since I buy them long enough that only the bolt shoulder is in the shear area. Threaded area would make the bolt shear easier. Also I don’t tighten the bolt very much but use two nuts to lock together so they don’t come loose.

 

[6869704x4]

I not sure I would go through all the trouble for the shroud. The diameter of the bolt/pin for the driveshaft is important. I can't remember shearing one though.

 

[jaxs]

Having been born on a farm during ww2, I'm telling you this is extremely abnormal and deserves better that an online chat.
It near makes me ill thinking of endless ways you could be killed from messing with this. You need someone with eyes and hands on to look at this before you even think of turning that tractor pto on again. Seriously, until you know what caused this and for certain it has been 100% corrected, it would make sense to buy a new mower rather than turning this rig on gain.

 

[NCL4701]

I’m having a hard time envisioning a reasonable scenario that would result in the shroud having any force applied to it beyond being impacted by flying pieces of the broken shear bolt, the force of which would be nowhere near enough to shear the four mounting bolts.

Did the PTO shaft totally disconnect from the gearbox????

If yes, you are risking your life and the lives of anyone nearby running it like that, so stop unless and until it’s fixed.

The way the shear bolt works on a round input shaft as it appears your gearbox has. In the absence of a shear bolt, the PTO yoke turns freely on the input shaft, but the PTO shaft will NOT come off because it’s held on by a circlip installed in a groove at the end of the input shaft furthest from the gearbox. If that circlip is missing, breaking the shear bolt would allow the PTO shaft to come off the gearbox input shaft. If it does that, it could (and likely would) allow the PTO shaft to flail wildly. That could explain the damage to the shield.

A flailing PTO shaft often causes extensive damage to the back of the tractor. It’s also not unusual for a flailing PTO shaft to permanently maim or kill the operator.

If somehow the shear bolt hit the shroud, there would be matching damage in the inside of the shroud.

I agree with @jaxs. In the interest of your health, you have to take the mower out of service until you absolutely know what caused the damage to shroud.

On the shear bolt issue, two suggestions. Double check the implement manual to make sure you’re using the correct grade. Use shear bolts, not generic hardware store Grade 2’s. Could expound on why, but this is already long enough.

That and busted shear bolts will irritate you. A missing circlip can kill you.