Woods Blower keeps snapping grade 5 bolts

[ruffdog]

The OP was doing fine with the grade 5 bolts, until he wasn't. Something changed.

It could be the shape of the bolts or quality of the bolts. The holes will also loosen up a bit with age which would add sloppiness and might shear easier.

 

[LouNY]

Something has changed, snapping bolts at an idle unloaded.
Even chineee grade 2 should be fine unloaded.
Something is wrong some place even though it turns fine by hand.
It could be in the impeller, the gear box, even the chain it's self or the auger.
Until the components are separated it will be looking for the proverbial needle in the haystack,
just not so many pieces.
It could be an issue which shows it's ugly hear at a faster speed then turning by hand achieves.

 

[Jchonline]

Bought a woods blower a couple of years ago for my 50hp Kioti and it works like a dream, but recently it has started snapping the grade 5 shear bolts. I can hand turn the auger and then I will turn on the pto, and it instantly snaps the shear bolt. I was working great the week before, but now it is snapping shear bolts. I figured maybe I needed to have the pto drive shaft straight out from the auger u- joint, and then I turned on the pto and SNAP! I have no idea why it is snapping the grade 5's. I bought some grade 8's but I am hesitant to use them for obvious reasons. Any ideas?

Did you buy them from Tractor Supply Co? Cheap garbage them bolts!

 

[KanakaRick]

Can you spin the input easily by hand? If you can, do you feel any unevenness when you do?

I’m thinking there may be a bad bearing in the 90-degree gearbox, which is causing
it to bind up when input is applied via the PTO, but not when you turn the impeller, sending the load in from the other side.

It is pretty new, and I haven't picked up anything that would have caused it to bind. When the snow is cleared, it turns very easily.

 

[KanakaRick]

Did you buy them from Tractor Supply Co? Cheap garbage them bolts!

No the local neigborhood hardware store

 

[KanakaRick]

Don't go to the grade 8 bolts. As suggested, try an alternate brand of grade 5.

Also thinking the "bad bearing/worn bushing" , as suggested by jigs could be the cause.

Obviously - something is binding up when you apply power. Is everything well greased up?

Actually, I haven't greased the u-joints.... maybe I'll try that.

Does the tractor ALSO have a foot clutch.

I know it isn't "needed" to engage PTO on most modern tractors. But if the clutch pedal does indeed disengage the PTO (it does on my Kubota MX)....by pushing the clutch, then engaging the PTO, it allows you to slowly engage the implement

So the foot clutch also engages the pto? Really? Didn't know that.... I may try that. It's worth a try.... it is dumping outside and I need that blower.

 

[KanakaRick]

I doubt if too many TBNers have a gear tractor with a live PTO anymore. I had a couple in the old days (Deere 670 and 790), and LD1's post exactly describes the process. I'll add one thing...if the tractor has a foot throttle, be prepared to "blip" the RPM when engaging the PTO.

What would bliping the throttle do?

 

[KanakaRick]

Yup, most of these small tractors anymore are HST. But up until 8-10 years ago....most still had a clutch.

Only recently have they gone away from that so they could put the split brakes on the left side.

Some like it that way. Personally I still prefer the clutch. Cause it still disengages the PTO. Doing alot of brush mowing....that's my first oh $hit instinct is to stop on clutch when something sounds amiss. And it also allows feathering the engagement.

I think the OP said his tractor was a 2002 model. I would think it still has a clutch.

The ONLY implements I use that I DONT feather the clutch to ease the engagement on are things with little inertial load. Like a seed spreader, or PHD.

Didn't even think of using the clutch.... I'll try that.

 

[RoyJackson]

So the foot clutch also engages the pto? Really? Didn't know that.... I may try that. It's worth a try.... it is dumping outside and I need that blower.

It does if you have a live PTO...

"What would bliping the throttle do?"
If you're a younger guy, and haven't had a vehicle with a standard transmission, you may not be familiar...
As the clutch is released, the engine may stall (sudden load on the engine). Blipping the throttle increases the RPM, providing more power and, hopefully preventing a stall.
Same thing applies when engaging a PTO powered implement...the sudden drop in engine RPM can stall the tractor's engine

 

[KanakaRick]

It does if you have a live PTO...

"What would bliping the throttle do?"
If you're a younger guy, and haven't had a vehicle with a standard transmission, you may not be familiar...
As the clutch is released, the engine may stall (sudden load on the engine). Blipping the throttle increases the RPM, providing more power and, hopefully preventing a stall.
Same thing applies when engaging a PTO powered implement...the sudden drop in engine RPM can stall the tractor's engine

It's live.... .as I am getting older.... I am starting to forget stuff. I wouldn't think that I would have forgotten to use the clutch.. but I guess anything is possible. The only time I use the pto is in the winter, so it's been 6 months since I have used it. CRS syndrome. Thanks everyone!

 

[Jims1025R]

Something has changed, snapping bolts at an idle unloaded.
Even chineee grade 2 should be fine unloaded.
Something is wrong some place even though it turns fine by hand.
It could be in the impeller, the gear box, even the chain it's self or the auger.
Until the components are separated it will be looking for the proverbial needle in the haystack,
just not so many pieces.
It could be an issue which shows it's ugly hear at a faster speed then turning by hand achieves.

This.

If you can tighten the nut on the shear bolt decently, without breaking the bolt - it's not a failing of the bolt that it's shearing. If the bolt is too junky (which could be found, if you really tried) tightening the nut would break the bolt.

Do not use stronger bolts:

Understand the system, examine for defects, and keep searching until you find whatever is wrong, and fix it correctly. Exactly the same reasoning as don't replace a blown fuse with one of a greater rating just because the correct one keeps blowing, fix the problem and use the correct fuse!

 

[KanakaRick]

Actually, I haven't greased the u-joints.... maybe I'll try that.

So the foot clutch also engages the pto? Really? Didn't know that.... I may try that. It's worth a try.... it is dumping outside and I need that blower.

Pressing the clutch doesn't affect the speed of the PTO... that's probably why I didn't try that.

 

[Deere Dude]

Try actual shear bolts from a tractor dealer. Just an idea.

 

[RoyJackson]

Pressing the clutch doesn't affect the speed of the PTO... that's probably why I didn't try that.

No, but engaging any load on the clutch does lower engine RPM

 

[KanakaRick]

So, there was a brief break in the series of storms, so I dug out the snowblower and put it back on the tractor. I greased every fitting copiously and attached the driveshaft to the tractor and turned the pto on...... and it didn't snap. So I am guessing the ungreased joints perhaps had something to do with it. We will see, but for now it looks like it may work. I'll find out tomorrow morning. Thanks for all the ideas.

 

[RoyJackson]

So, there was a brief break in the series of storms, so I dug out the snowblower and put it back on the tractor. I greased every fitting copiously and attached the driveshaft to the tractor and turned the pto on...... and it didn't snap. So I am guessing the ungreased joints perhaps had something to do with it. We will see, but for now it looks like it may work. I'll find out tomorrow morning. Thanks for all the ideas.

Best of luck and keep us posted

 

[KanakaRick]

I am now thinking that it was a cheap batch of grade 5's. When I snapped another today by sucking a tree branch in the blower, I went through several more snapping, and then I used a little longer and older purchase date bolt and it worked fine. I think it was just cheap shear bolts. Thanks for everyone's replys.

 

[michaelgs]

Just wondering, is the pto shutting off then when engaged the engine is then at over 2000 rpm? This kind of jolt was causing my snowblower to shear bolts. Mike

 

[Jac65]

Sounds like a bad batch of bolts. You can also throttle down the idle as low as it will go, press the foot clutch and engage the PTO then ease off the clutch and see if the bolt will hold at min rotation speed. you can throttle up from there and see if they hold.

 

[KanakaRick]

So, I am guessing that some loose fan bolts were the cause of the snapping of the shear pins. Boy what a tricky way to tighten the fan bolts, but I got it tightened up. I haven't tried it yet, as I needed to put my rear blade on to cut some ice on the driveway, and I (apparently) forgot to disconnect the wiring to the chute rotation and the deflection motors, so when I drove away, I ripped all the wiring out. I take 2 steps ahead and 3 steps backwards. A big DUH moment. When I get everything wired up I again I will reconnect to see if I am snapping shears again.