Shear pin stuck in auger shaft

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  #1  
Old 11-21-17, 06:31 AM
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Angry Shear pin stuck in auger shaft

I own a Craftsman 24" snowblower, model 88957.
Last winter I caught a brick in the auger and snapped 2 of the shear pins on the right side. The inner shear pin was easy to fix, used a punch and a hammer and it popped out with ease.
The outer pin has refused to come out. I have used a bath of WD40, heat, a drill bit (only to loosen), a punch, a nail (to chip away) and screaming at it!

I finally had to take the entire auger out of the snow blower and take the blades off.
I an now left with the shear pin stuck in the shaft. It appears if the pin expanded in the hole. A couple of good whacks with a hammer and punch and this thing will not budge.

Any ideas???????
 
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  #2  
Old 11-21-17, 06:55 AM
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Drill it out. Have a good one. Geo
 
  #3  
Old 11-21-17, 09:22 AM
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WD-40 does little in this application. You need to use Liquid Wrench or PB Blaster rust dissolver.

The pin is softer than the shaft so it can be drilled out.
 
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Old 11-21-17, 11:28 AM
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If it is the correct shear pin, it is likely harder but more brittle and could be tuff drilling, but is the best option if possible.

Maybe find a press or make up a rig with a C-clamp and small sockets or pipe...
 
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Old 11-22-17, 02:13 AM
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If it is a shear pin it should be fairly soft.
File the side that is the least peaned and use a drift punch slightly smaller than the hole the pin passes through to knock it out.
A drift punch is one with a flat punch surface.
 
  #6  
Old 11-22-17, 03:55 AM
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I'd be curious as to whether PYG_42 has owned this machine since the beginning or if it's possible that a prior Owner crammed something into that shaft other than the appropriately sized Shear Pin ?

Some people get annoyed with the behavior of Shear Pins even though the Pins are just doing their jobs and sacrificing themselves to save more expensive components.
 
  #7  
Old 11-22-17, 05:14 AM
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All shear pins I have seen have two grooves located the shaft diameter apart. The 2 pictures attached don't show any indication of a groove so my guess is this is not a normal shear pin. If the OP doesn't know the history of this shear pin, the best approach is to drill it out because it could possibly be a threaded among other things. If the pin can't be drilled out because it is harder than the drill bit ( not an import), he will need to get a new shaft.
 
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Old 11-22-17, 06:11 AM
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Might try going by a garage or machine shop and see if they can get it out with a hydraulic press.
 
  #9  
Old 11-24-17, 07:44 AM
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I purchased the snowblower straight from craftsman. It arrived it a box and required some light assembly.
I can not say that this machine had a previous owner, but I am almost certain it did not.
All the other shear pins were part number 738-04124A ShearPin,.25 x 1.50.
I dont know why this on is so different or difficult.
I am going to purchase a bottle of PB Blaster rust dissolver and give that a try along with filing and drilling.
( I almost bought a bottle of PB, but opted for the WD40 since It had a many more uses.
 
  #10  
Old 11-24-17, 09:43 AM
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Heat may be required to get that rusty hag out but i don't know if that shaft is hardened and/or what that kind of heat would do to it.
 
  #11  
Old 11-25-17, 05:21 AM
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The way that shaft looks it might be best to replace it,it appears to be quite worn around that pin.
Geo
 
  #12  
Old 11-27-17, 06:29 AM
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Angry

The shaft looks "worn around the pin" because I have been hammering at it for a month.

I ended up working with a friend to use a drill press to get the pin out. Unfortunately he did not drill straight through. I had to use a hand drill and a punch to pop the rest out.
Now the space below the pin is bigger than it should be.
I can get everything together and the pin does not slip or slide.
I was considering using some epoxy putty to fill in the space?
Thoughts?
Suggestions?
 
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  #13  
Old 11-27-17, 07:49 AM
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I can get everything together and the pin does not slip or slide.
I would think you'll be fine, the pins also goes through the auger so it'll stay all lined up.

Nice pictures
 
  #14  
Old 11-27-17, 08:45 AM
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If you find you need to fill the gap, wrap a shear pin with Teflon tape or plastic wrap and insert the pin then fill in the gap with JB weld after it has set you can easily remove the pin. Have a good one. Geo
 
  #15  
Old 11-28-17, 04:24 AM
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Your shear pin will work just fine the way it is.
If you use any type of adhesive to make it look pretty it will be knocked off in just a few min of snowblowing.
 
  #16  
Old 11-28-17, 12:23 PM
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The only way to repair that would be to have it welded shut, then re-drill it.
Probably overkill for what the shear pin actually does..

Basically, the gouge is not deep enough to weaken the drive shaft, and it's not going to prevent
the shear pin from working, so I wouldn't worry about it.
 
  #17  
Old 11-28-17, 12:50 PM
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Oh, quick FYI, about how to unstick a shear pin, bit late now, but might help somebody else-

First thing, mount the shaft so the shear pin is vertical.
Use a propane torch to heat up the shaft, just "hot" not red hot.
Flame goes against the shaft, not the pin, so that the heat expands the shaft, and breaks if free from the pin.
Then, once it's hot, hold ice cubes against the shear pin to cool it and shrink it.
You want the pin as the bottom of the shaft so the water drips down, and doesn't cool the shaft.
Turn 180 degrees and repeat on the other side of the shear pin.
Repeat 2 or 3 times If you're really lucky, you'll hear a "tink" as the pin and shaft separate.
Most of the time, you're just opening up microscopic cracks in the corrosion between the pin and shaft, which helps for penetrating oil.

Next a little chemistry, gloves & goggles are required to make a penetrating grease mix.
Take a tiny bit of battery acid from an old battery, (literally a few drops) into a glass jar.
mix1:1 with dishwashing soap. Mix WD40 and clean axle grease.1:1
Then, mix the acidified soap and penetrating grease 1:1.
Leave in an open glass container. Apply with the tip of a screwdriver.

Dab a bit of the mixture onto both exposed shear pins, let sit for a few hours.
You might see bubbles after 20 minutes or so, rather like hydrogen peroxide on a cut.

Soap works because one end likes oil, the other end likes water.
Soap dissloves oil by coating the oil to create tiny oil droplets can be washed away by water.
This mix is doing the opposite, soap lets tiny droplets of acid dissolve into the penetrating oil/grease. The acid can get down into the cracks and crevices in the corrosion between the pin and the shaft.
 
  #18  
Old 11-29-17, 07:13 AM
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Next a little chemistry, gloves & goggles are required to make a penetrating grease mix.

I know there are a lot of different opinions on this but have you ever tried 50/50 acetone and ATF? I tried this years ago changing the rear spring U bolts on my truck and it worked. Then again, maybe anything would have.
 
  #19  
Old 11-29-17, 05:52 PM
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Haven't tried that mixture.

Hmm, the lubrication and anti-oxidation properties of ATF would be helpful as penetrating oil, and iron rust does act as a catylst for acteone-alcohol redox reactions:

So, quick guess without doing the equations:
the low molecular weight acetone creeps deep into into narrow crevices, reacts with and is catalyzed by rust to pull H2O molecules out of the rust resulting in propanol (rubbing alcohol). The propanol diffuses back out, anti-oxidants in ATF convert the propanol back to acetone, and the cycles repeats.

So, working theory, the acetone extends the reach of the bulky ATF antioxidants so that tiny molecules of acetone reach into tiny rust crevizes, and open them up. As the rust is dissolved, the ATF oils move in and lubricate the enlarged crevices.
 

Last edited by Hal_S; 11-29-17 at 06:51 PM.
  #20  
Old 11-29-17, 06:57 PM
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A good review for the 50/50 solution in the link below. Have a good one. Geo

https://www.garagejournal.com/forum/...ad.php?t=59511
 
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