# How to reduce your MTD gearbox to shrapnel...



## brassmonkey (Nov 10, 2015)

Hi my blower brethren. Been awhile since posting as I had carted the semi-restored beast up to the woods for driveway clearing duties on the couple of weekends we venture into the bush. I was hoping to return triumphant with vids of it eating up long driveway drifts with ease. 

Here we are all loaded up like the Beverley Hillbillies....I think I need another strap on there...










Alas, a tragedy has befallen my machine which I'm not sure how to recover from. 

Yesterday we arrived at the lot in the bright sun to a beautifully snow covered landscape. I trudged over to the old girl, got the tarp off, and she started on the second pull, which I took as a good omen after the careful carb rebuild. 2nd pull after ten weeks in deep freeze outside. (There's no electricity at the garage for starting til I can get into the cabin and flip the breaker. Can't get to the breaker til I use the machine to get to the cabin door...Catch 22!). 

I cleared a nice path the rest of the way to the house and had a last drift to cut through which was made up of snow which had slid off the roof. It was however snow covered ice...so it wasn't til the machine insisted on climbing over it rather than through it that I realized something was amiss and this wasn't no fluffy drift. I levered away for awhile, back and forth til we gave up and got out the spades and picks and I reluctantly parked it. 

We got through and after a well earned lunch I went back out to clear the second most important trail of the weekend....to the outhouse! 

Again, started right up but when I put it in gear, it turned hard right and tried to head off into the bush. Wha?! Didn't take long to determine the pin holding the right wheel on was sheared. Dang - when did that happen? Had no spares (dumb) but found a bolt that would suffice. Installed that, fired up, engaged the drive and heard, after a brief shudder, a distinct snap. This was accompanied by cessation of all forward movement. Ho boy. 

Checked my newly installed wheel pin and it was fine. With growing dread I pulled the bottom pan and was confronted by the following horror show. 











Yep. Snapped chain, chewed gear sprocket deeply gouged friction wheel. If you look closely you can see the two gears are no longer even aligned. How can that be you ask?

Check out the axle...the bushing holding it fast in the chassis popped out, allowing the entire works to shift out of alignment. 










The metal links in the chain of course don't allow for lateral shifting so snapped like a popcorn necklace. 











Not before seriously damaging the drive sprockets however. Dang it! The levering stress I introduced tackling that ice hill before realizing it was hopeless was too much for that 30 year old bearing I guess. I should have realized the sheared wheel pin was an early warning something was amiss. It didn't break trying to dig in for traction. The wheels would just spin. It broke because the axle was being pulled out the other side of the gear box. Arrrrrgh. 

Finding consumable parts like tires and scraper blades for a machine this old is one thing. Drive chains and gears? Not so confident. :-(

Maybe I can repurpose some bicycle chain and sprockets or some such scheme. Perhaps the gears have enough material that a repaired chain will still bite. I dunno...

All thoughts welcome!


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## wil (Jan 1, 2014)

Wow! THAT takes a lot of power to break a chain!

The chain and sprocket, if not available via the OPE guys, you can visit your
Fastenal or Grainger for replacement. Chains and sprockets are considered 
"stock" replacement items.

I think a bicycle chain may be too small. Maybe a motorcycle chain!


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## bwright1818 (Dec 2, 2014)

I'm not into MTDs so I will be of no real help...but thank you for sharing your story of pain. I thought I was the only one who, despite his best efforts, went out and destroyed something just about every single time it snowed....Usually, with me, it's something small like a shear pin or I find something big is ABOUT to happen and stop.....but it's always SOMETHING. (This, of course, is why I NEED seven snow blowers. I mean, am I right here????) Your story made me feel better. Good luck getting that baby back to life. The battle of man against nature MUST go on!!!


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## brassmonkey (Nov 10, 2015)

Thanks guys - appreciate the support! Perhaps there might be some hope finding parts. 

And yes, bwright, you are definitely in good company when it comes to snowblower snafus. Seven machines, eh? I like that plan!

After pondering and poking around a bit more I noticed that when the axle is in the proper position there's about a gap of about an inch between the right wheel hub and chassis. Had there been some kind of collar there preventing the wheel and axle from trying to slide left, the problem may not have happened. Makes me wonder if there's a part missing. 

If I get this working again I will try to address this. Even a short piece of pipe over the axle down there should do it.


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## 94EG8 (Feb 13, 2014)

The little gear on that double sprocket is high wear item. You can still get them easily, both from MTD and in the aftermarket. When we had one of those machines we replaced them every 2 or 3 years. The sprocket on the axle may be harder to find. The machines we had had a differential so it was a little different and that sprocket was discontinued. I finally bought a generic sprocket with the correct number of teeth from princess auto, but I could only get it in #40 rather than #420 so I used the wider #40 chain. It always seemed to work fine.


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## bad69cat (Nov 30, 2015)

That should all be repairable.... just going to take time to locate parts. Clean the chain up and look for a number stamped in the links -- shoul dbe a 35 or 40 I would think. That can be bought in lengths and make your own at a farm store. The sprockets are probably availabe on ebay or parts sites. Take measurements and tooth counts so you can match that up. The bushing/bearings are available at many places. My favorite: McMaster-Carr


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## Shryp (Jan 1, 2011)

I wonder if your axle has 2 holes. The inner hole is for the wheel to be pinned to it and the outer hole is for just the pin so the wheel freewheels for easy steering. If you pinned it to the outer hole that might have allowed the bearing to slide out.


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## HCBPH (Mar 8, 2011)

Looking at your pictures, I can see why it broke.

First off, you've got some 'poor replacement' work done on it. The bearings on the axel look to be gone. I've attached a picture of what the bushing I think should be there, another machine showing how they look on the inside and a conversion to roller bearings I've done (there's a thread here on how I have done that). That should fix the axel issues, though you might need to add a collar on each side to keep the axel centered if you use bushings. The big thing is finding the outer part of the shell that holds them onto the frame. It probably be easier to convert to roller bearings.

Now the pulley is another issue. Unless you can find a parts machine or that pulley somewhere, all is not lost in all likelyhood. If you can find a new/replacement gear, a good machine shop should be able to turn off the old one, fit and weld a new one onto the pulley and have you back in business. Just make sure the 2 sprockets are aligned on reassembly.

On the issue of the chain itself, check out places that sell parts for farm equipment. Looks like a fairly common size and I've bought boxes of 10'-15' of chain before. You just need a chain breaker or way to seperate the length of chain you need.

Hope that helps.


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## brassmonkey (Nov 10, 2015)

Shryp said:


> I wonder if your axle has 2 holes. The inner hole is for the wheel to be pinned to it and the outer hole is for just the pin so the wheel freewheels for easy steering. If you pinned it to the outer hole that might have allowed the bearing to slide out.


Bingo! We have a winner! In my haste to get going again, combined with my inexperience on the machines, I pinned the wrong hole. My father-in-law pointed this out to me after consulting on the problem yesterday. I feel pretty silly. 

Thanks HBC for the roller bearing idea. Going to look into that since as you say the machine has been bodged together in the past. 

You too badcat for the chain info.


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## bad69cat (Nov 30, 2015)

I think that info should get you going..... it's worth the effort to fix her up. Good machines when they are running well. next year will be a different story!


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## 94EG8 (Feb 13, 2014)

HCBPH said:


> Looking at your pictures, I can see why it broke.
> 
> First off, you've got some 'poor replacement' work done on it. The bearings on the axel look to be gone. I've attached a picture of what the bushing I think should be there, another machine showing how they look on the inside


That machine doesn't use the bearings you've pictured. I owned a bunch of them, they just use a simple brass bushing.


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## HCBPH (Mar 8, 2011)

94EG8 said:


> That machine doesn't use the bearings you've pictured. I owned a bunch of them, they just use a simple brass bushing.


Yup - having a senior moment, said bearing and ment bushings like in the picture I posted. Sorry for the confusion.

Here's the thread on converting the large frame Craftsman's to flange bearings: http://www.snowblowerforum.com/foru...ance-forum/570-plastic-bushings-bearings.html
Same process just need to modify the dimensions of the adapter used to center the bearing over the hole for the axel when drilling the holes to mount them to the tractor unit. Big thing would be to find flange bearings that fit between the chassis and the wheel when the axel is aligned where it should be for the chain to run straight.

Paul


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## 94EG8 (Feb 13, 2014)

HCBPH said:


> Yup - having a senior moment, said bearing and ment bushings like in the picture I posted. Sorry for the confusion


They don't look like anything you've pictured though, they just have a flange on one side with flat sides to keep them from turning in the hole. 

OP: The double sprocket is MTD Part # 713-0194 expect to replace it every few years if you blow a lot of snow. The sprocket on the axle is part # 713-0320. The chain is #420 and 38 links, MTD part # 713-0215


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