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Minding my P's & Q's
2,039 Posts
Discussion Starter #1
It really got messed up this time.

Frame under the tractor bent and cracked. Eccentric Bearing on power transfer shaft broke (Locking part broke away). Bearing carrier Power transfer shaft needs fixing. Lower 15T sprocket worn and needs to be replaced. Upper impeller 45T sprocket wore out and needed to be replaced.

Some of this narrative is out of order. Should have started the post to begin with and added to it as I went.

Have a Craftsman GT # 917.251522 and Snowblower attachment 842.242560.
Snow blower has a long wide C channel frame that fits under tractor. And bolts to the blower housing.


PTO has belt to a pulley at rear of frame, with a spring tensioned idler. That pulley is mounted to the input shaft on a right angle 1:1 gear box on bottom of frame.

Gear box out put to a 7/8”, 33” long, drive shaft.

There is a union (6” collar) that connects gear box out put shaft to the drive shaft. Has wood ruff keys and 1/4” through bolts at each end.

Drive shaft has a pillow bearing in a carrier mounted just before shaft terminates in a 15 tooth chain sprocket.
#40 Chain transfers power to a 45 tooth upper sprocket mounted on impeller shaft.
Chain has a spring tensioned idler sprocket that mounts in a bracket.

Last Spring (2019) the chain was pretty noisy. Put snowblower away figuring I would look at it over the summer. Did not happen.

Fall 2019 gave snowblower a good look over. Found several bolts were loose on frame. Removed them, cleaned and used blue loctite, reinstalled. Installed blower on tractor.
Took it out for a couple of 2 to 4” dry powder snows. Still had a lot of chain noise. Brought it in garage about Dec 10.
Kept thinking it was the idler sprocket. (Had my blinders on) Did what I could to fix it up. Realign. New sprocket, oil with bar oil. Nothing worked. Stayed noisy.



Idler sprocket rides on the bottom of a swing arm. Arm has a 1/2” shaft on the top that runs through 2 holes in the bracket. Both holes were badly wallowed out.
Added solid 1/2” ID pipe to the place the shaft goes through the idler bracket.
Drilled out center of pipe to fit 1/2” shaft on swinging idler arm. Used a 33/64” bit.


Put pipe in line with holes, put shaft through the pipe and both holes on bracket from back side and had the flat swing arm clamped to back side of bracket to keep shaft perpendicular to bracket. Tapped all as far up ward as it all could go. Clamped in place.

Welded pipe to bracket at both ends. Drilled hole in top of pipe to oil it. Figured this would give the shaft more surface to ride on instead of just the 2 holes in bracket. And there would be far less slop.

Worked OK, but did not fix the problem Spent 2 weeks messing with this off and on. Before I found the real problem.

Dec 24 took blower off the tractor. Stood it up on it's nose. Looking at bottom of frame, I could now see the problem. Top of C channel frame where idler bracket and carrier bearing bolted on was cracked. Idler bracket and carrier bearing bolt to the frame with the same 2 bolts. Idler bracket on top, bearing under the frame.

And there were cracks running out towards rear of frame.
Under the idler bracket the frame was cracked and broken out in a rectangle around the bottom of the bracket.


Highlighted cracks with white.

I had checked alignment of sprockets and all looked good. Adjusted position of the idler 3 or 4 times. But that was w/o power to the blower. Even made a video of the chain and sprockets running so I could view in slow motion. Did not see a problem.

Too much oil on the top of the frame from oiling the chain to see cracks when looking from above.

Something at some time made the chain taunt, pulled up on drive shaft sprocket, Bent and broke the frame. I did pop 2 or 3 impeller shear pins this fall. Was out in 4” of powder at the time. Did not pick up any rocks I was aware of. May have happened last winter and did not realize it.

After frame broke when power was on, shaft was riding high and allowed lower sprocket to be way out of alignment. Chain ate up the front of the 45T sprocket.

Front Power shaft bearing is broken. Clamping/locking part broke away from the bearing. Will need new bearing.

Jan 2 Found the carrier for the bearing has spread apart and will not hold bearing tight. Bearing was blue from heat from spinning in the carrier.

Shaft was wore down from spinning in the bearing. Will need to be built back up in that area.

Rear end of Power shaft loose in the collar, and worn badly. Bolt through the power shaft and collar was bent. Bolt hole through power shaft is elongated. Will need to be weld filled and re drilled. End of shaft will need to be scatter welded and machined down to 7/8”.

Large upper sprocket is worn out. Needs a new one. 45T x #40 chain.

Sprocket on power shaft is 15 tooth, 7/8 bore. Welded to end of shaft.
It is also worn and needs to be replaced.

Hit my 10 attachment limit. More tomorrow


Minding my P's & Q's
2,039 Posts
Discussion Starter #2
Front of frame where the idler bracket and front bearing are, frame edge was bent up for the first 1-1/2” Used 2 pipe wrenches to grip and bend it back in place.





Have plate of 1/8” steel to weld on the top of the frame. 7” X 2-1/2”
Going to put another plate behind that one. Bump against the first one, and weld in place.
Going to drill 2 new 3/8” holes in second plate, 5/16” from front edge.
Might hang the front bearing there so it will be a second set of bolts.




Found another crack along the side. Welded and patched that one too.


Old shaft stuck out 1-1/4” from front edge of bearing to face of sprocket.
In the new position the shaft will stick out another 1-1/4” farther than it did.
Total will be 2-1/2” from face of sprocket to front edge of bearing. Not sure the 7/8” shaft can support that distance.
With front bearing moved back 1-1/4”, there may be room to put a piece of steel on the underside where idler bracket bolts on. That will strengthen the steel frame.

12/30 Almost done with top of frame.
Jan 2 finished welding and painted all the metal.

Finally figured out how to work my new auto darkening mask. Had to keep switching back to my old helmet. Was going to return it but figured it out.
Found battery was not making good connection. Fixed it. Bent out the outer contacts for the ring.

Once I had battery making good contact, I could figure out the switch settings.

Intuition said to push the switch down to WELD when I want to weld.
Was wrong. You push switch up to GRIND, exposing the word ON next to the WELD marker.
Means WELD setting is ON. Other way means GRIND setting is ON. Owners manual was clear as mud.


Rats, hit my 10 picture limit again.

Will see if I can do another reply right away.

Minding my P's & Q's
2,039 Posts
Discussion Starter #3 (Edited)
Other image of mask switch
On edit, put the correct image here showing WELD ON

Must be limit of 10 per reply. Not per day.

Jan 2 Found the carrier for the bearing has spread apart and will not hold bearing tight. Bearing was blue from heat from spinning in the carrier.

Jan 3 Bent it down a little bit in the vise. Holds tight now. (Later I just went with a new carrier.)


Could also see the shaft had been spinning in the bearing. Shaft wore down there. Locking collar of bearing had broken away. Surprisingly it would still lock to the shaft, but I replaced it anyway.

Need new 45 T upper sprocket. And hub.
Decide it was a good time to speed up the impeller. Ordered new 42T sprocket and hub from NAPA. Also ordered new locking collar bearing. Figured 42T instead of 45T will speed up impeller just a little bit. If not enough can put on a 40T later.

They could not get the 42T sprocket. NLA.
Did get the hub, but was wrong one. Was too deep I found out later.
They got the bearing in, called me, but they lost it inside the store over the weekend. Refunded my money.

All I ended up with was the hub for the upper sprocket.

But not all was lost. Worked out better I got my parts else where. Just took more time.

Ordered a 15T sprocket From Big Bearing Co on line. With no hub. Sprocket was suppose to have a 7/8” hole that would fit over drive shaft, no hub, and weld on.

Also ordered 2 bearings, with carriers. Together they were half the cost auto parts place wanted. And these came with new bolt on carriers.

Got the bearings, with new carriers, but they sent me a 17T sprocket with a hub built in, rather than the 15T sprocket I ordered. Sent them an email.


Checked with the brain trust on MTF.

17T instead of a 15T on the drive shaft should increase the impeller speed about 130 to 150 rpm. If I go with a 45T sprocket on top.
That should be about right. So decided to use the 17T sprocket to speed up the impeller.

Thread about that here:
15T to 17T Sprocket

Bought a 45T sprocket at Fleet Farm for half the cost of other place. And it fit the hub I already had.


Was surprised at how much chain drive items they keep stock on.
They had the bearing and carrier in stock. But no 42T sprocket.
Did have the right 15T lower sprocket, but by now was committed to the 17T.
Will just drive there next time I need parts.

Old 45T on top of new 45T.
Notice all the wear on the side of the old sprocket. And teeth have gotten sharp.
That happened recently, like last spring and this fall, when lower sprocket, and idler sprocket were lifted and chain was running off kilter.

When I removed the chain this time it was pretty beat up. Was new last spring. Only ran a few hours.
Could tell it had gotten hot. Had kinks in it. Streached about 3/8". Tossed it out.

Minding my P's & Q's
2,039 Posts
Discussion Starter #4
Drive shaft needed a lot of work.

New machine shop I found looked it over and said a whole new shaft would be cheaper.
So he built one for me. Took a week.
Only charged me $31.50 for materials and labor. Was expecting more.

Got the stuff from the machine shop. Then I finally get a return call from the place that shipped me the wrong 17T sprocket. Told him it was too late to return it. Was forced to use it in order to get my snowblower working again in a timely manner.
Made sure he understood I will not be buying anything else from them in the future.

He machined off the hub on the 17T sprocket, and welded sprocket to the shaft.
This is old shaft and sprocket, and the new sprocket before he machined it off.

Cut a key way into the shaft instead of a wood ruff key slot. He told me he was going to do that. And that was OK, I had key stock at home.



Was going to make a new union (Collar), but he checked out the old one and it was OK.
Fit tight on the new shaft, not wallowed out inside at all. Wear was on the old shaft only.



He welded the hub to the 45T sprocket. But forgot to machine down the hub to be flush with the sprocket on the back. I had to grind that extra 3/8” of hub off later with the grinder so it would fit. Was not a big job.
If I left it as is, that hub sticking out would hit the bearing for the impeller shaft and not go on the shaft far enough.

He also drilled the 1/4” through hole in the hub off a little on the far side. Went through the set screw hole on the side to start, but hole was not drilled straight. Had to file out the newly drilled hole a little to get the bolt through. That sucked. Took a long time filing with short strokes.

I did not compare new shaft to old shaft when I brought them home. I should have.

Had a hard time getting sprockets to align. Found he had made the shaft over all a 1/4” too long. And he drilled the 1/4” through hole in the rear of new shaft off about a 1/8” from where it was located on the old shaft.

Center of new hole was exactly where the edge of the hole was on the old shaft. So off by an 1/8” there.



After I hung the old shaft back in place to see how that sprocket lined up, I found that hole was off almost an 1/8” from where it needs to be. Might have come from the factory that way. May be why chain has always been noisy since I owned it.

His mistake compounded the problem so now hole was off by almost 1/4” from where it really should be.

Back face of sprocket to center of 1/4” hole needs to be 31-3/4” to fit right.

The through bolt holds the shaft from moving forward or back. So 17T sprocket on new shaft was about a 1/4” too far forward and would not line up with 45T sprocket. Found it was 0.225” off and needed to be moved more towards the rear of the shaft.

Was using a thick flat aluminum bar held against the face of the 45T sprocket. Then slide it down to see where edge of 17T sprocket should be. Could measure between bar and sprocket face with stacked feeler gauges.



More to come.

Minding my P's & Q's
2,039 Posts
Discussion Starter #5
I ground off the weld on the 17T sprocket and shaft down to flush with the face of the sprocket.
That took off the weld and allowed sprocket to be moved on the shaft. (No picture of it ground off.)

This is from before I ground it down. Getting ready to grind it off.

Tapped the sprocket farther down on the shaft until I had moved it 0.225 closer to the rear end.

Went to weld it and found with the bad catarcy in left eye my depth perception was way off. Even with welder turned off I could not put the stick where I aimed it. Was a half inch off from where I aimed it. I did manage to tack it on by feel. Then took in down to a neighbor to have him weld it on.
Can see a weld dimple in cut face of shaft. That is one place I hit it with stick trying to weld. Tack welds are on the back side in this picture.
In picture it is 0.225 down from where it was. Ready to weld.

All in all not too impressed with the work this new guy did. But I still managed to get it done.

Took a week to get the shaft back from the machine shop. So while I waited for that, I tried to straighten the bends in the frame, weld up the cracks, and reinforce the frame.

Drilled a 1/8“ hole at the end of every crack. Used a Dremel tool with a cut off wheel to clean and bevel the metal along each crack. Both top and bottom of frame. Grind flat, clean it up. Then weld again. Then grind it down again.







Minding my P's & Q's
2,039 Posts
Discussion Starter #6
Added a 1/8” thick piece of metal to the top of frame where the idler bracket bolts.

Wanted to cover the cracks and reinforce the frame. Figured it would not be a problem to raise the idler bracket a little bit.



Could not extend metal over the full width of the frame. Would have to go under the the 2 upright brackets where they mount to top of frame. Did not want to re do or adjust bolt holes on the front of the bracket where it bolts to blower housing. With hindsight I am thinking I should have. Would have been stronger.

Drilled 2 new 3/8” holes 1-1/4” back from original mounting holes. Was thinking I would mount the bearing there. Then have just the idler bracket mounted in the 2 front holes. Later I decided against it. Worried an additional 1-1/4” of the drive shaft hanging out past the bearing at the drive sprocket end might cause vibration, and put more stress there. Can move it later if I need to.

Did not put additional steel on bottom of frame thinking it would put the shaft bearing out of line too much. Left the bottom pretty rough thinking I only need to mount the bearing there.

Turned out the front lip of the frame still had a bend in it from L to R. Curved upward.
Everything on top all welded. Did not want to try and hammer that out.

Used a piece of aluminum bar laid on the frame and under the shaft to measure with. Could use a stacked feeler gauge between bar and drive shaft to find if shaft was in line up and down with frame. First measured next to gear box at rear of frame. Then measure up front close to bearing. Back from bearing where frame was still straight.




Minding my P's & Q's
2,039 Posts
Discussion Starter #7
First found I needed to put an 1/8” thick piece of steel between frame and bearing mount to bring the bearing in line with the gear box.



Ground down welds and surface of frame. Checked again. Welded steel in place. Had to grind down steel plate 0.018” after I welded it in place. Mounted bearing. Checked again. Did this several times. Finally got it so shaft was in line, up and down, when bearing bolted in place. Was still off 0.004” but figured that would be OK.

Then worked on left to right alignment. Found gear box is mounted a little off center. Closer to left side of frame. Used a divider to measure close to the gear box, then measure at bearing always using left side of frame to measure off of.

Had to file left side of mounting hole a little bit to get it there.

Grew weary of using dividers to measure. Plus I knew once I had the blower mounted on tractor I would not have the room to use them. So I cut and filed a piece of steel to use as a feeler gauge between the shaft and the inner left frame. Much easier to use.



Ended up having to remove and remount the idler sprocket bracket many, many times during the repair.

Idler bracket had slotted holes on the bottom to allow for movement forward and backwards to adjust it. With carriage bolts holding it on. Square part of carriage bolt head fit in the slots. They were a pain to tighten. Had to use a dowel rod and push down on the bolts when I needed to tighten or loosen. Had to do this blind when frame was mounted to tractor. So always needed a 3rd or 4th hand.

Came up with a fix. Found 2 metal pieces I could bolt to the bottom of the bracket to hold the bolts down in place. Drilled holes and tapped for 8-32 machine bolts. Screwed them on.



Flipped it over, cut off bolts, filed flush with bottom of bracket. Worked like a charm.
Could remove bracket with bolts in place, and reinstall with bolts in place. Much easier to
to start locking nuts, lock washers, and tighten them.

But still needed a 3rd hand to hold drive shaft in place as I tighten the bearing carrier down. Got a long 3/8” eye bolt and bent the eye into a hook. Would have liked to use a 1/4” eye bolt, but 3/8” was what I had on hand.

Drilled a hole in the left side of frame near the bearing for the hook bolt to go through. Put hook over shaft, lightly tightened the bolt until feeler gauge fit right. Then tighten the bolts that held it in place.

Now I could use one hand to tighten the nuts with a socket wrench, and the other to hold idler sprocket bracket in place. That was a huge help once I had blower mounted and was trying to align idler sprocket with the other 2 sprockets.

Minding my P's & Q's
2,039 Posts
Discussion Starter #8
Put chain on sprockets. Tried a new 32 link chain that I had pre cut for old set up.
Came around and I could have put a master link in to hold it.
Thought I would add a half link.
Ended up with a full link. Which makes sense. Added 2 teeth to lower sprocket so a full link would fill those 2 teeth. So now I have to cut replacement chain at 33 links.

Post about that is here.
Adding a half link. Then a full link.

The post there also is end of the ordeal. Finally got the tractor and blower fixed and out of the garage and back in the barn. Took about 7 weeks after I first started this repair.

This really is a simple machine and the fix should have been simple. But seemed to run into one problem after another.

Had I noticed earlier that the sprockets were that worn and replaced them, the frame probably would not have gotten cracked.

I was checking the sprockets, but was watching for the teeth to get much more pointed before replacing them.
That sure happened fast this fall.
Live and learn.

02/09/2020 Was out with it today blowing about 3" of dry snow. Just before I put it away I popped the impeller shear pin. So problems may not be over.

Minding my P's & Q's
2,039 Posts
Discussion Starter #9 (Edited)
Got it inside and let it dry off over night. Took the chain cover off, found idler sprocket was running on top of outer edge of chain.


Only way I can really see the alignment of the idler sprocket is to jack up the snow blower housing and tractor about 20" and support it with jack stands, and crawl under it.

Looking up I could see idler sprocket was out of alignment. Eyes still wonky from cataract in left eye. Really hard to focus on things that close.


Loosen the 2 bolts that hold the idler bracket. Stand up and tap the bracket forward with a hammer, or use a crow bar to pry it rearward, to move it where I guessed it needed to be.

Hook is to hold drive shaft in place when I loosen and tighten the nuts.

Climb back under and eye ball it. Tighten bolts, get back up and rotate impeller by hand. See if it was quieter, or made noise. Then crawl back under and eye ball where the teeth of the idler sprocket were riding on the chain.
Found when I tighten the bolts the idler bracket was moving. So I had to move it more than I needed to so when I tightened the bolts it would move to where I wanted it to be.
Also found if I laid on my back on the floor and reached an arm up and around the scraper bar I could turn impeller from underneath and watch how the sprocket rode on the chain.

Turned out the idler sprocket was at an angle. Had to move right side of the bracket about a 3/8" farther towards rear of machine than the left side to get the sprocket to be straight.
Finally able to get sprocket straight and riding in center of chain. Should have included a picture of that.

Still concerned the 45T upper sprocket was wobbling I set up a dial indicator that would show if top of sprocket was running in and out. Put it on a real solid mount this rime. Result showed it was running - 0.045" out and +0.005" in. Total movement 0.050". Off about 3/64".

Have to leave it for now.
Took tractor outside and ran the blower. Watching the chain movement and sprocket wobble is not really visible to me. But at least Idler sprocket no longer hopping around.
Idler arm and shaft only has slight movement forward and rear ward as sprocket moves.

Having cataract surgery today on left eye. Won't be able to lift anything for awhile, which includes getting down on the ground then lifting myself back up to standing.
So will leave it for a week or 2, then maybe with my sight better I can come back to it and see what I need to do. Either that 45T sprocket is welded to the hub a little off, or the impeller shaft is slightly bent.

Minding my P's & Q's
2,039 Posts
Discussion Starter #10
Had the cataract surgery today. Could not have gone better. That eye still blurry tonight. But after a good nights sleep should be fine tomorrow. Just can't lift anything.

Super Moderator
30,854 Posts
JP you fixed a bunch of issues you were having, a lot of reinforcing so hopefully no future issues with that snowblower and frame. Also hope that your eye heals fully!

Minding my P's & Q's
2,039 Posts
Discussion Starter #12
JP you fixed a bunch of issues you were having, a lot of reinforcing so hopefully no future issues with that snowblower and frame. Also hope that your eye heals fully!
Eye turned out great. Could not have gone better. So good to have my depth perception back again. It was pretty tough doing anything with it off so much.
And to see distance so clearly with out glasses is amazing.

Took me a while to get the blower fixed. Ran into many unexpected problems.
But I think I finally have it right.

Had 5" of wet snow yesterday. Snowed until after dark. Left it over night so it was frozen this morning.
Took the tractor and snowblower out. Chain was a little noisy at first.
After a half hour of working the chain noise went away. It really got quiet.
I assume there were a few light burrs and sharp edges on the sprockets. Took a bit to wear the chain in.

Blower is very quiet now. Quieter than it has ever been since I owned it. Hard to hear any chain noise at all now.

I think that little bit the sprocket was too far forward on the original drive shaft (1/8") must have been rubbing too much on the chain all along. Never checked alignment of the sprockets before. Always assumed they were right from the factory.
And being this was the first chain drive snow blower I have ever operated, I was thinking the chain drives just make that much noise when running that hard.

Now with the 2 sprockets so well aligned, the sprockets are riding in the center of the chain. And so is the idler sprocket. Everything is just humming along.

Snow blowing today was enjoyable again. Not worrying if some thing was going to fly apart.
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