Sheer pins

[tsteahr]

Hello,

I have a front blower on order for my Massey GC2410. based on what I have read here, I have asked the dealer include a bunch of spare sheer pins with delivery. In my past experience with a single stage front blower on my lawn tractor as well as a 9hp Simplicity walk behind I have never had to replace a sheer pin.

Under what circumstances do people tend to loose pins? I understand if you hit something solid, but can you break a pin by just trying to put to much snow through the blower at once?

Thanks.

 

[amkfken]

You should get a few with the blower, 2 different lengths, rocks seem to raise he** with them, go to a hardware store with the samples and get some more (2 or 4) of the various lengths.
I have broken a few in 2 years, replacements work as well as "factory pins", just picked up an oval rock the size of 2 softballs, killed the engine-didn't bother any shear pin or any part of the driveline--go figure!

Just Lucky!!

 

[irvingj]

tsteahr- the first time I had to replace a pin was last year, blowing the same neighbor's house down the road... just TOUCHED the stone wall and one of the shearpins let go. Other than that, a 1" diameter buried branch (we tend to get a lot of that around here) or good-sized stone will accomplish the same.

Those pins are designed to shear --lot cheaper than a gearbox-- so I don't mind it when they do their job.

Don't know how I managed to get through the first winter I had it without breaking one.... though that may have been because I got the 2310/blower in February, and had most likely already cleared any hidden debris with the walk-behind. (That ol' Toro 8-HP may not throw snow as well as it used to, but it'll still zing rocks real well!)

 

[JerryK]

The PTO shaft shear pin takes the most abuse. If you have a new blower, before it is broke in and loose, it is real easy to pop the clutch a little too fast and break it. After the blower gets some hours on it, you still stress the PTO shear pin each time to engage the blower. Over time, this stress will finally do in the shear pin...and this is normal.

 

[JerryK]

You will also notice, over the years, that the pins tend to break in a direct relationship to how cold it is, how cold you are, how far you are from any tools or spare parts, and how bad your day has been going......

 

[PILOON]

You will also notice, over the years, that the pins tend to break in a direct relationship to how cold it is, how cold you are, how far you are from any tools or spare parts, and how bad your day has been going......

Don't you know it!

Must be another Murphy's law rule!

Try replacing pins when you have Renaud's syndrom! (fingers go white without any feeling)

I now keep a minimum of 6 spare pins with the tractor at all times.
Funny as last year I could replace 3-4 every outing and so far this year only 1 for 4 outings, go figure.

 

[tsteahr]

Interesting point about a new blower being tight and engagement fatigue. I'm guessing engaging at about 1500rpm is best? I have not engaged my pto with any load on it yet. Is there a spot in the pto engagement lever travel where there is some slip? Something akin to using a manual transmission clutch where a smooth engagement provides just enough slip to not have a shock or jerk rather than just poping the clutch?

 

[JohninCT]

I'm guessing engaging at about 1500rpm is best? quote]

That's the way I've always engaged PTO attachments... engage at low RPM and then throttle up to PTO speed. In a normal situation I also disengage the opposite... throttle down to low RPM then disengage the PTO. This minimizes shock loads on the drive train.

 

[JerryK]

I usually do the throttle down to engage/disengage the PTO thing. Especially with the wood chipper and the flywheel effect.. Since my blower has some time on it, I usually just feather the clutch pedal, when I remember too..... There are always those 'oh ****' moments, but that is just part of life....... Usually get away with it, unless my fingers are froze...long way from the barn....etc....

 

[tsteahr]

The GC2410 has a mechanical PTO engagement lever. There is no clutch per say with the HST. Can these be engaged gradually (ie over the course of one second) or to they engage with a sudden grab (a couple tenths of a second) like a electric pto engagement on a lawn tractor?

 

[DMW]

The GC series is an "instant on". Lower your rpm to idle and engage with the blower lowered. Raise your rpm after it is engaged. Have the spare shear pins and tools handy. Pieces of wood and ice will break the shear pin. Excessive snow should just bog the engine. Raising the 3ph while running the snow blower can put enough extra strain to break the shear pin on a new blower. I let mine run at idle for c. 1/2 hour spinning freely to let the gears mesh after breaking several pins and it seemed to help a lot.

 

[tsteahr]

The GC series is an "instant on". Lower your rpm to idle and engage with the blower lowered. Raise your rpm after it is engaged. Have the spare shear pins and tools handy. Pieces of wood and ice will break the shear pin. Excessive snow should just bog the engine. Raising the 3ph while running the snow blower can put enough extra strain to break the shear pin on a new blower. I let mine run at idle for c. 1/2 hour spinning freely to let the gears mesh after breaking several pins and it seemed to help a lot.

Excellent Info. Thanks very much!

 

[irvingj]

M-F SCUTs actually do have a "clutch assembly" in the PTO engage mechanism-- but it ain't much, and there's no way to engage it gradually. It's called a "clutch pack" IIRC. It sounds like it's slamming in, but that's the way it is....

You can see it below, #12. Kinda like a motorcycle clutch.

 

[jpm1]

I buy CHEAP low grade bolts by the pound and if i'm real ambitious I put each one in the drill press and with the bolt spinning take a hacksaw and put ever-so-small a cut in the bolt shank. This gives you a bolt just like the dealers "shear-bolt" BUT. . . a whole lot cheaper. A shear-bolt is just a cheap "SLIP" clutch that doesn't reset it self. Oh by the way. . .snow blowers should have been renamed "Rock Chuckers"

 

[lungdoc]

I broke my first one the other day backing into a large hidden rock - worked like a charm. Interestingly what the Agro-trend manual describes as shear pins and what dealer supplied (10mm x 50mm gr 8.8) aren't shown on diagram and wasn't what broke. I presume these are related to shaft/gearbox, what broke is a bolt/pin (5/16 x 1 1/2 gr 2) connecting two greased surfaces in the cross shaft - obviously designed to break and allow cross shaft to spin freely.

I now have both types, still not sure where the first type goes as part isn't shown on owner's manual diagram, just listed in the accompanying parts list! Fairly sure it's at the blower end of PTO shaft but it isn't really clear!

 

[DMW]

I haven't broken the cross shaft shear pin yet, but have sheared the one on the tractor end of the PTO shaft several times. The shear pin is number 14 in the PTO shaft diagram.

*edit* if the PTO shaft wasn't replaced .

 

[lungdoc]

Thanks - I think I found it later. I have a different PTO shaft I believe as unit came with a separate manual (Comer Industries Driveshaft manual) but the principle looks exactly the same. What had me confused was that part #32 on blower exploded parts diagram is the same shear pin but isn't labelled in the diagram - nothing above part 31 has a label!

 

[MEhorseFarm]

I live off a dirt road and this morning the snowplow driver left me a 4" oval shaped surprise in the pile of snow at the end of my 500-foot driveway. I broke the PTO shear pin so I had to head back to the garage to replace it. It only took about 5 minutes to replace but like someone said earlier, you will always seem be the farthest away from your pins and tools when it happens.