Shear pin nightmare

[seville009]

The OP must be confusing Grade 5 bolts by calling them Grade 3?-for 3 hash marks on the head.
Grade 2 usually make lousy shear bolts because they seldom break cleanly and tend to help elongate the hole.
Wonder what Erskine recommends?

Manual calls for grade 2

 

[grsthegreat]

I also have that same problem with my hydraulic unit. If I shut it down and road the tractor between jobs, it freezes up if the weather is just right. I have to get out and I carry a 2x4 with me to manually wedge the center rotor while tractor is off. Then I get back on and it runs great. If I don’t do that, the hydraulid bypass kicks in and nothing turns. Only happens when temp is near freezing …..doesn’t occur when super cold. I guess the snow has to melt some and get behind the fan. Than freeze again.

also, glad I do-not have shear pins anymore. I went thru 100’s of them before this rig.

 

[Dave M7040]

Thanks for the photos.
The blower was originally used on a ford tractor and now is on a different one.
Was the length of the pto checked so there is no bottoming out when blower raised and there is sufficient overlap.
Dave M7040

 

[airbiscuit]

My guess is that the electric PTO switch is unforgiving of any ice buildup.

Re-engage the PTO at absolute low idle.

 

[Robin Veerman]

Also has the gear oil been changed recently? Yearly is recommended. Not because the oil is worn out, but the high chance that it’s got moisture in it due to condensation. The moisture may be freezing up inside the gearbox causing the issue. I use a synthetic Marine gear lube in my blower…

 

[Dman1981]

Leave your shear bolt a little loose use a stover nut or double up nuts
Will bend but not break right away anyway. Tightening them down makes them pop

 

[Robin Veerman]

If the shear bolt breaks, make sure to always replace it with a same category bolt (grade 8.8). It is necessary to
always maintain this bolt very tight, in order to keep the efficiency of the shearing mechanism

...appears to refer to a metric grade 8.8 bolt. I think that is roughly the same as an SAE grade 5

To Dman above, That’s opposite to what my manual says. Shear bolts are to be tightened snug. However not like a gorilla would, as it would already be primed to break if done like that….

 

[bigtiller]

Leave your shear bolt a little loose use a stover nut or double up nuts
Will bend but not break right away anyway. Tightening them down makes them pop

I like using stover nuts, even though they are expensive. I also have good luck with nylock nuts and a drop of Loctite. But the shear bolts should ALWAYS be drawn down with the proper torque.

The last thing we want is for the bolt to be loose.

 

[Dman1981]

I like using stover nuts, even though they are expensive. I also have good luck with nylock nuts and a drop of Loctite. But the shear bolts should ALWAYS be drawn down with the proper torque.

The last thing we want is for the bolt to be loose.

That's for sure enough loose nuts behind the wheel already

 

[Seven Gables]

One thing I’d make a good inspection of is the Shear coupler itself. Pull it off the tractor pto and with the shear bolt removed see how much wiggle, play and slop there is between the two rotating halfs. Over the years vibration in the driveline can cause excessive wear to it.
Have you ever checked to see if the shear bolt is staying snug after a hour or two of use? I had a Loftness blower quite few years back probably had good 1000hrs on it and the pto shear coupler was getting worn and sloppy. Two problems it caused was shear bolt to self loosen and sometimes back itself all the way out or break the shear bolt upon the quick Electronic engagement.
Running the the blower tipped at a slight angle will throw the tractor pto shaft and blower gearbox shaft out of parallel increasing the vibration wear to this shear coupler.