Land Pride snow blower SB1574 shearbolt sprocket hub question.

[mcmxi]

I'm getting the SB1574 snow blower ready that I bought a few months ago through Craigslist, and one of the issues I noticed is that the two flanges for the shearbolt sprocket hub won't align (see red arrow). The shearbolt is missing and I figured it would be easy to rotate the sprocket so that that holes in the flanges line up. The sprocket should turn easily without the shearbolt installed right? I removed the driveshaft and am trying to get the sprocket off but it's really hard to remove.

If anyone has this snowblower or equivalent, am I missing something? Surely the sprocket should turn fairly easily once the shearbolt is removed. I get the impression that maintenance was optional for the original owner. There's a zirk fitting on the sprocket body and I squirted grease in there when I bought the blower, but I'm not sure why it's so hard to get the sprocket off the driveshaft.

 

[RCW]

Don't have that blower, but they should be relatively free to turn.

That's what shears the pin, after all....

Is there enough clearance to allow the 2 flanges to spin independently....i.e., they're not jammed together?

You greased it, but still bound up..I'm wondering if it'll will take some penetrating oil, or more disassembly to get everything lubed and freed up?

I'm obviously just speculating...maybe first pull the zerk out and spray a bunch of PB Blaster down there, or whatever penetrant you like? Let it soak in and try again? Bunch of old dried out grease in there? Or no grease at all, and it's seized to the center shaft?

 

[UpNorthMI]

Sounds like good advice from RCW, I would recommend going the full way and disassembling things fully so you can clean both the shaft and sprocket where the shear pin connects them. Then I would reassemble and grease things well.
I would mount the blower to your tractor and run it with no shear pin to make sure that there is no drive to the auger, then fit a correct shear pin.

At the end of the season grease the shaft / sprocket, remove shear pin and run on tractor, next season re grease run on tractor check for shaft slippage, fit shear pin.

I recommend a similar procedure with all shear pin protected attachments, it is so easy for things to bind up, rust up etc. that will stop the shear pin working and something much more expensive will get damaged.

 

[Dave_eng]

Not an uncommon event. You at least have a grease fitting, many shear bolt areas do not.

I would not spend a lot of time trying to disassemble it.

In the first snow you will suddenly find the auger not working which will be your clue to install a new shear bolt.

The torque your tractor pto will exert on the two flanges is far greater than anything you can do with tools.

I am assuming that the auger is rotating now without the shear bolt.

It may even break free just by accelerating and slowing down the pto speed quickly so that the inertia of the auger is working for you.

Dave

 

[mcmxi]

Not an uncommon event. You at least have a grease fitting, many shear bolt areas do not.

I would not spend a lot of time trying to disassemble it.

In the first snow you will suddenly find the auger not working which will be your clue to install a new shear bolt.

The torque your tractor pto will exert on the two flanges is far greater than anything you can do with tools.

I am assuming that the auger is rotating now without the shear bolt.

It may even break free just by accelerating and slowing down the pto speed quickly so that the inertia of the auger is working for you.

Dave

Well, between doing other projects today I managed to remove the sprocket and bearing from the driveshaft and this is what I found. I'm pleased that I got everything off so that I can clean up the driveshaft, make sure the sprocket is free to spin, get everything greased and get it back together.

I can only speculate but I think it's possible that the sprocket was hammered on with the zirk fitting protruding into the inner sleeve diameter, or a piece of zirk fitting sheared off and was trapped between the sprocket sleeve and driveshaft. That could explain the axial gouge that runs all the way from the end of the driveshaft. The deep scoring must have been caused by the driveshaft rotating inside the sprocket once the shearbolt broke. I'm wondering if a zirk fitting would be hard enough to do that but I can't think of any other plausible explanation. There appeared to be plenty of grease inside the sprocket sleeve with no corrosion of any significance.

I wouldn't be surprised if the original owner was running the snow blower without a shearbolt on the driveshaft coming out of the gear box. There's a shearbolt on the input driveshaft too but I haven' t got to that yet.

 

[Tim Horton]

Three summers ago now we got a gently used Buhler 3pt snow blower.. As prep for winter I took out every bolt, one at a time, on bearing mounts and lubed them with copper anti seize compound..

Also pulled off the sprocket you show in the diagram.. There was not any damage to the sprocket or shaft like shown in the next picture..

Again I cleaned shaft and sprocket hub with abrasive cloth and assembled with anti seize.... Also the pto shaft shear bolt got the same clean and lube treatment... Knock on wood, I have had no problems yet..

 

[mcmxi]

After moving a few trailers around with the MX this morning I spent 30 minutes on the sprocket and driveshaft. The inner sprocket sleeve was in bad shape so I cleaned it up (removed high spots) and did the same to the driveshaft. The sprocket now slides back on easily and spins easily too whereas before I couldn't get it off without using a big hammer. I removed the zirk fitting and applied some 200 grit polishing compound and will shine up the mating surfaces a bit. Any grooves will now act as a grease holding feature.

The advice to not address this issue and figure out what's going on could have been disastrous for the gear box if an auger obstruction would have broken the shearbolt. Gear boxes are expensive so I'm going to drain the oil and look for any signs of damage. Hopefully the original owner didn't have an auger obstruction once the sprocket seized up. If he did, there's a chance the gear box is damaged. It doesn't feel like it is when I spin the auger or driveshaft but it's possible.

 

[mcmxi]

As I was cleaning up the parts above for reassembly I "threaded" a paper towel through the tapped zirk fitting hole to remove any dirt or polishing compound and look what came out! It's really hard so when it was covered in grease I thought it was made of steel. After cleaning it in solvent I realized it was a rock chip of some sort.

So I have a new theory. I'm speculating that the original owner removed the zirk fitting at some point and somehow managed to get a small rock chip approximately .100" x .200" into the threaded hole before reinstalling the zirk fitting and crushing the chip into the driveshaft. Pure speculation but it seems reasonable. The zigzag axial gouge that I thought was caused installing the sprocket was most likely caused by me (and the chip) as I hammered the sprocket off the driveshaft.

Unless any other issues crop up I'll consider this case closed. Thanks for the helpful feedback.

 

[mcmxi]

I got everything back on the blower yesterday afternoon without incident. I greased the spline on the outboard side of the gear box and adjusted the chain idler sprocket to get proper chain tension. I checked the gear box oil and it was full and looked to be brand new, and based on rotating both the auger and the pto driveshaft the gear box seems to be fine. I also checked the input shaft shearbolt which was present and looked ok. I greased every bearing and u-joint, disconnected and drained all four hydraulic hoses, applied anti seize to a bunch of bolts and started to straighten out a piece of sheet metal that was damaged by a rock or similar. It's snowing a little at the moment but I feel that I'm just about ready to go if I need to push or blow snow. I'm hoping for lots of snow this year so that I can put this monster of a blower to the test. Next year I'll take care of priming and painting a bunch of spots where the paint had decided to head south for the winter.

 

[Toivo]

I don't mean to hijack this thread, but wondered if i could ask a follow up question. I'm using my SB1574 for my first winter. Prior breaks of the drive shaft shearbolt has left the two flanges spinning freely for easy bolt replacement. However, broke the shearbolt the other day and now the flanges are jammed with the holes out of alignment. I ran it thinking it would break itself loose so i could replace the shearbolt. No luck after running it for about 45 min. Question is, am i at risk of damaging the gearbox if i continue to run it, or is it time to start tearing it apart? Happy to start a new thread if that's more appropriate. Thanks for any feedback.

 

[kubotasam]

I don't mean to hijack this thread, but wondered if i could ask a follow up question. I'm using my SB1574 for my first winter. Prior breaks of the drive shaft shearbolt has left the two flanges spinning freely for easy bolt replacement. However, broke the shearbolt the other day and now the flanges are jammed with the holes out of alignment. I ran it thinking it would break itself loose so i could replace the shearbolt. No luck after running it for about 45 min. Question is, am i at risk of damaging the gearbox if i continue to run it, or is it time to start tearing it apart? Happy to start a new thread if that's more appropriate. Thanks for any feedback.

The shearbolt is there for a reason. You really need to address the problem and fix it correctly. If you do not correct this something expensive is going to break when you are least able to deal with it. Think in the middle of a big snow storm!!

 

[mcmxi]

Prior breaks of the drive shaft shearbolt has left the two flanges spinning freely for easy bolt replacement. However, broke the shearbolt the other day and now the flanges are jammed with the holes out of alignment.

This sounds EXACTLY like the situation I discovered with the blower I bought.

 

[Toivo]

This sounds EXACTLY like the situation I discovered with the blower I bought.

Certainly sound advice Kubotasam. I don't want to be dead in the water during a big storm.

That's what i thought Mcmxl! However, i was hopeful that maybe it's likely or even common for the bolt not to break cleanly and a piece of it to get stuck between the flanges causing the hang up. It's a new machine, so there shouldn't be a rock in there. I guess tearing into it is the only way to find out, unless warranty??

 

[DustyRusty]

It isn't a warranty claim if you broke a shear bolt. I have found that sometimes when a shear bolt breaks, the holes no longer align, and tapping on one side of the blower or the other will help to align the holes. The only problem that I can see, or technically can't see is that the broken piece is still in the shaft, and the grease makes it difficult to find the hole. Once you find it, drive the broken piece out with a thin punch and a gentle tap of a small hammer. Once it is out, install the new shear bolt, and then mark the shaft as to where the hole in the shaft it. It will make the next broken shear bolt a lot easier to locate the hole.

 

[mcmxi]

That's what i thought Mcmxl! However, i was hopeful that maybe it's likely or even common for the bolt not to break cleanly and a piece of it to get stuck between the flanges causing the hang up. It's a new machine, so there shouldn't be a rock in there. I guess tearing into it is the only way to find out, unless warranty??

I don't know if the rock chip I found was responsible for the galling both on the driveshaft and inside the sprocket hub but I'll be very interested to see what you discover if you decide to disassemble the driveshaft. On the bright side, it's an easy job to remove the driveshaft and sprocket from the blower. It may or may not be easy to get the sprocket off if you have galling like I did. Please give us an update when you have a chance. That sprocket needs to spin freely if the shear bolt breaks to avoid the possibility of expensive damage to the gear box.