Snowblower power issue

[tooltroll]

Greetings!

A bit of background: I'm helping out with snow clearing at a hotel I'm wintering at, using their equipment, so it's my first time running Kubota, a brand I'm not familiar with. I've got 40-odd years experience as a contractor/maintenance worker, and have operated many different machines over the years. Unfortunately, I don't have access to the manuals.

The tractor is a GX2680 with a 2-stage snowblower rear mounted on a three point hitch, and earlier today I caught a chunk of 2x4 someone had left near the edge of the parking lot. I shut down as soon as I heard the racket, and cleared the auger and impeller, and I suspect I've snapped a shear pin somewhere. The odd (for me) thing is that when I turn the (now unjammed and freely rotating) auger/impeller by hand, I can see the PTO shaft turning, so it looks as if the PTO is still connected to the snowblower drive train. I can also see the PTO shaft turning when I engage PTO from the cab, so I know the tractor is still turning the shaft, but then the blower won't run. . . I can't see how the shaft seems to be still connected at both ends, but I can't get power to the blower.

As I mentioned, this is my first time on a Kubota, so I'm wondering if there's some sort of safety/overload clutch or something on the blower that needs resetting, or is there something (the busted shear pin, maybe?) that's providing enough friction to still turn the shaft by hand but not enough friction to run the blower when the tractor spins the shaft, or. . .

I'm stumped! Any advice would be appreciated!

 

[McMXi]

There are typically two shear pins. One on the PTO shaft i.e. between the pto output shaft of the tractor and the blower gearbox, and one on the output shaft from the gearbox that drives the chain gear. You shouldn't be able to turn the auger much at all before you get significant resistance, unless a shear pin has broken. If you're turning the auger and pto shaft is turning then you probably sheared the pin on the pto shaft.

 

[tooltroll]

Thanks for the quick reply!

The auger and impeller both turn together when one or the other is cranked by hand, so it looks like you're right and I snapped the pin between the PTO and the blower gearbox, I just don't get why the PTO still turns when I hand-crank the blower, as if it's still connected. (At least, the snowblower end of the PTO seems to turn when either hand cranked or engaged from the tractor, which I find odd.)

Where/how do I access the suspected sheared pin? Sorry for the noob-ish question, but I have no Kubota experience or manual (at least until Monday, maybe, if the owner even knows where it is, and there's snow in tomorrow's forecast).

 

[McMXi]

Not sure what model you have but here's the location of the two shear pins on my SB1574. #4 in both drawings. The shear pin is right after the coupler that slides over the input to the gearbox on the blower. Sorry for the initial error.

 

[tooltroll]

Excellent! Looks pretty similar to the model I'm using, PTO straight to the impeller with the chain drive for the auger. Thanks a bunch, now I know where to look, maybe save some time.

 

[McMXi]

Here's a photo of the shear bolt and the u-joint at the gearbox of the blower, but looking more closely, if this bolt has failed then the PTO shaft shouldn't rotate. I bought the blower used four years ago and have never had to replace a shear pin, just greased the u-joints and lubricated the chain. I need to replace the gearbox oil once winter is over.

 

[McMXi]

Excellent! Looks pretty similar to the model I'm using, PTO straight to the impeller with the chain drive for the auger. Thanks a bunch, now I know where to look, maybe save some time.

If both shear bolts are ok, then it might imply a damaged PTO on the tractor. I sure hope not, but check these two shear bolts first. It's always possible that someone stuffed a grade 8 bolt in where a shear bolt should be used.

So when you fire up the tractor and engage the PTO the blower auger's don't rotate, but with the tractor off you can easily rotate both augers and the PTO shaft by hand? If that's the case it might be worse than just a broken shear pin.

@North Idaho Wolfman will know the answer I'm sure. Good luck and keep us posted if you don't mind.

 

[tooltroll]

I suspect what I'm seeing is the blower side of the joint spinning when I hand crank it, and the tractor/shaft side spinning with PTO engaged. I had a hard time getting close enough to see much in detail either way, being behind the blower looking overtop when hand-cranking, or the tractor shutting down when I left the seat with PTO engaged (a safety feature, I guess) so I'm looking through the plastic 'cab' he's got on it.

I don't think I've buggered the PTO on the tractor (I hope!) I haven't tried turning the actual PTO shaft by hand, but I do see something spinning when it's engaged. I will certainly keep you posted, and thanks again!

 

[McMXi]

I suspect what I'm seeing is the blower side of the joint spinning when I hand crank it, and the tractor/shaft side spinning with PTO engaged. I had a hard time getting close enough to see much in detail either way, being behind the blower looking overtop when hand-cranking, or the tractor shutting down when I left the seat with PTO engaged (a safety feature, I guess) so I'm looking through the plastic 'cab' he's got on it.

You're probably right. Hopefully it's the shear pin at the PTO shaft u-joint closest to the gearbox. You can pop open the "windows" on the plastic housing and get to the shear bolt. See photo above.

 

[Bearcatrp]

Hope who ever used it last time didn't put a regular bolt to replace the sheer pin and you actually damaged the tractor. Suggest you replace all sheer pins with the correct pins to insure they are done correctly. Sure would suck if this happened. I would remove the snow blower and engage the PTA to insure its working properly.

 

[tooltroll]

Huzzah!

After getting a good look in the light of day, I found the PTO shear pin is indeed the culprit. Found it straight away, thanks to McMXi's comments and illustrations. Thanks again!

 

[McMXi]

Huzzah!

After getting a good look in the light of day, I found the PTO shear pin is indeed the culprit. Found it straight away, thanks to McMXi's comments and illustrations. Thanks again!

Thanks for following up and good to hear that it was something simple. I bought my used snow blower in September of 2021 and did buy spare shear bolts from Kubota, but only the ones for the connection between the output shaft of the gearbox and the gear that drives the chain. There was an issue at that connection that I resolved and the shear bolt is the right one since I installed a new one.

I still have the spares since I've never broken a shear bolt, but @Bearcatrp makes a good point re unknown equipment. I probably should have bought a new shear bolt from Kubota for the PTO shaft since I don't know if it's the original factory bolt or if the owner ever replaced it, and if so, with what. I'll stop by the dealer this week and get a couple of PTO shaft spares and swap the one out that's there just in case.

 

[Russell King]

If it is the joint in post #6 that sheared the pin, and the blower broke a shaft, and would actually still work with that pin sheared…

I think that joint needs some maintenance and was not working properly. There are some ball bearings inside that joint and everything may be rusted together. That would be why the shaft snapped and I would get the joint spinning freely and replace the bearings inside of the joint before using it too long.