How much damage am I likely to have done to my new tractor?

[oosik]

I've never hit anything that has "dead stopped" my JD X570 mmm. But since I insist on "mowing" my pocket gopher mounds - quite a bit of hidden gravel.

Every spring I resharpen/balance the three blades. I take special care to grind out or sharpen the nicks in the blades also. Life goes on ...............

 

[ScotNH]

I’m not familiar with that particular mower, but with my MMM, I assumed the belt between the blades and the PTO would slip before doing serious damage.

 

[dodge man]

I don’t think I’ve had that happen with my current JD but I did with my previous Kubota BX. It never seemed to hurt it.

 

[sea2summit]

Also, why doesn't this brand new Kubota mid-mounted mower attachment have a slip-clutch or shear pin??

Because it's got a belt? I can't remember for sure, is the center one direct drive off the gear box?

 

[dougtrr2]

I was under the impression that the cupped washers/nuts holding the blades on also acted as a slip point.

Doug in SW IA

 

[Rdrcr]

I had it happen with my B2601 w/60” MMM when I hit a hidden stump. No damage to tractor or mower.

Mike

 

[dadohead]

Aside from the strain on the mower, can someone please explain to me what having a tractor stop-dead like this can do to the tractor/engine? What tractor parts are being stressed exactly? What kind of repairs might I be up for if they keep doing this? (hypothetically...I WON'T keep doing this!!)

Also, why doesn't this brand new Kubota mid-mounted mower attachment have a slip-clutch or shear pin??

I seriously doubt that you've hurt your tractor in any way. I'm a retired JD tractor/mower engineer. The reason mid-mowers don't have a mechanical 'fuse' in the system is that it wouldn't help. Most of the system's energy is in the running mower; the drivetrain is seeing high rpms but low torque. When the mower is shock loaded, most of the reaction forces go to the blade, spindle, and spindle pocket... a slip clutch wouldn't change that. Unless you have a 'timed' mower, the blade joint is probably just a self-tightening bolt. There is a little slippage but not much. Much of the engineering in the blade joint is to deal with the inertia in the other two blades at impact so they don't unscrew themselves, fall on the floor, and fail the stake test.

Good idea to pull the mower for inspection. Fingers crossed!

 

[CausticUrbanCoast]

Aside from the strain on the mower, can someone please explain to me what having a tractor stop-dead like this can do to the tractor/engine? What tractor parts are being stressed exactly? What kind of repairs might I be up for if they keep doing this? (hypothetically...I WON'T keep doing this!!)/QUOTE]

As diesels use compression to combust, stopping it dead means it is unable to combust on the cycle (so you do not shock the pistons and rods). Diesels also have the capacity to tolerate running backwards if the situation arises.

You stand more of a chance of damaging your transmission or mid-PTO drive.

And everyone is correct, a belt will typically fail before any shearpin will, and if tensioned properly, before any metal damage (aside from blade edge usually, old and rusting decks will have the towers destort the deck).

 

[IndyIan]

My buddy broke the pto shaft on his little kubota with a 4' bushhog hitting a few Christmas tree stumps every year. But it had over 3000 hard hours on it, mostly mowing using the full hp so I think your odd stoppage will be fine.

 

[PILOON]

I was snow blowing and the auger found a scrap of 2 x 4 and stalled the diesel engine.
Shear bolt did not do its job!
While very concerned , I have not observed any detrimental effects but I still worry about long term effects.
Mind U over the years I have sheared many bolts on my gravel drive and no effects.

Worst area is where the city plow creates snow banks at my entrance since the road is gravel based and who knows what the city plow dragged along and dumped here.