# Auger belt slipping - bad belt or something else?



## airlyss

Hi guys,

Great forum and first post here! I have a circa 1987 Toro 521 two-stage snowblower with a 5hp Tecumseh engine. I'm having a pretty bad belt slip problem - auger spins fine without load, but completely stops spinning when even a little snow is put in. Shear bolts are in tact - I pulled the belt cover and saw belt wasn't even moving under load.

I pulled the belt out and what has me scratching my head is that the belt still looks really good - no bad threads sticking out and teeth are in tact. The belt is a few years old, but the machine hasn't been used much since replacement. Do these belts go bad/stretch out even when they look practically brand new? Is there any way to isolate whether its the belt or a bad tensioner? Any help is appreciated, thanks!


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## Ingersoll444

Welcome to the snowblower forum!!

A belt will streach its most when new. Could it maybe have been too long to start with? Has it ever worked well with the new belt???


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## abumpa

airlyss said:


> - I pulled the belt cover and saw belt wasn't even moving under load.
> 
> no bad threads sticking out and teeth are in tact.


Not familiar with your particular unit, but are you saying the belt has teeth that mesh with corresponding teeth on the pulley?

If this is the case and the belt is not turning, and is not damaged, I would look for the drive pulley turning on the shaft under load, unless you can see that the belt is so loose it doesn’t contact either pulley.


Geared pulleys and belts are very tough and when they do slip the belt gets destroyed pretty fast. You say your belt is good so I suspect the pulley is turning on the shaft.


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## airlyss

abumpa said:


> Not familiar with your particular unit, but are you saying the belt has teeth that mesh with corresponding teeth on the pulley?
> 
> If this is the case and the belt is not turning, and is not damaged, I would look for the drive pulley turning on the shaft under load, unless you can see that the belt is so loose it doesn’t contact either pulley.
> 
> 
> Geared pulleys and belts are very tough and when they do slip the belt gets destroyed pretty fast. You say your belt is good so I suspect the pulley is turning on the shaft.


Hmm...very interesting point. Remind me again, which one is the drive pulley? The small upper one connected to the engine, or the large lower one connected to the auger assembly? 

The belt is definitely coming in contact with the pulley, since the auger does spin when its not under load - so I don't think its an overly loose belt.

I'll have to take a closer look at the pulleys to see if they are slipping on the shaft. I just pulled the belt, but didn't think to check the condition/functionality of the actual pulley. I've mainly worked with ribbed automotive belts, so haven't seen many of these geared belts.

Thanks to both of you for your help!


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## indypower

Can you post the actual model number? Looks like "38062".


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## abumpa

Drive pulley is on the engine. Driven pulley is on the auger drive shaft. At least that is the way my Ariens is. As I said I am not at all familiar with your unit. However if the auger turns when under power, but stops turning when a load is applied, then something is slipping and you should be able to see it. 

Are your sheer pins intact?


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## airlyss

indypower said:


> Can you post the actual model number? Looks like "38062".


Sure, it is model #38052.


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## airlyss

abumpa said:


> Drive pulley is on the engine. Driven pulley is on the auger drive shaft. At least that is the way my Ariens is. As I said I am not at all familiar with your unit. However if the auger turns when under power, but stops turning when a load is applied, then something is slipping and you should be able to see it.
> 
> Are your sheer pins intact?


Yes, the sheer pins are intact - auger blades don't move freely when I turn them by hand. If the drive pulley is turning on the shaft, what is the recommended fix - a new pulley or can I simply replace the bearing? I'm at work currently so can't look at it, but will check it out first thing when I get home tonight.

Thanks again!


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## abumpa

airlyss said:


> If the drive pulley is turning on the shaft, what is the recommended fix - a new pulley or can I simply replace the bearing?
> Thanks again!


Some pulleys I have seen use a set screw, some have a roll pin. There should not be any bearings associated with the auger drive pulleys, with the possible exception of the tentioner pulley. The drive pulleys need to be solid mounted to the shafts they turn or are turned by. 

As I said I am not at all familiar with your model machine. I have been making general suggestions based on my understanding of how my Ariens works. You will just have to work your way down the drive system until you find the problem. If the belts aren’t slipping on the pulleys, and the pulleys aren’t slipping on the shafts, then the next place to look is the auger gearbox, and then the sheer pins. That’s about all there is to it unless your machine is significantly different than the Ariens.


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## BOSMECH

Check if there is a woodriff key sheared and also if there is some allen screws that need tightening on the pulley


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## indypower

The drive pulley (the 1 that is on the auger) has a woodrift key and a set screw. Chances are the woodrift key is broken. To replace the key, you will have to remove the bucket from the tractor to remove the pulley. Yep, it is a lot of work for a 75 cent part.


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## airlyss

Hey guys, ok so I've uncovered the problem - its actually not the drive pulley slipping, that is on solidly on the driveshaft. The problem is that the belt tension is waaaay too loose - I mean barely any tension whatsoever. 

What has me stumped is that the belt does not appear stretched at all - I measured it and its almost exactly 29.5", the length of the standard belt according to the manual. So, the belt appears is the right length and in good condition, the drive pulley is working as it should....so the only other problem I could see is that the auger assembly and pulley is somehow positioned "too close" to the drive pulley - if I could "pull" the auger pulley further away from the drive pulley, this would lengthen the distance btw the two pullies and increase the tension. 

Does this make sense and can this be done?


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## indypower

Your problem is the idler pulley is not tensioning the belt. when you press the engagement lever, the idler pulley should tighten up the belts. Idler pulley is item #1 in "engine assembly" diagram.

https://lookup3.toro.com/partdex/back2lst.cfm?xCaller=Toro&o=2&x=2833


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## airlyss

indypower said:


> Your problem is the idler pulley is not tensioning the belt. when you press the engagement lever, the idler pulley should tighten up the belts. Idler pulley is item #1 in "engine assembly" diagram.
> 
> https://lookup3.toro.com/partdex/back2lst.cfm?xCaller=Toro&o=2&x=2833


Thanks indypower. The idler pulley is tensioning though and the belt is still loose. Even when I manually move the idler pulley as far in as possible to "engage" the auger, there is still about 1-inch of travel in the belt. Without it engaged, there is closer to 2-3 inches of travel.

Can a belt really stretch out an inch over time?


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## Wayne195

airlyss said:


> Can a belt really stretch out an inch over time?


 No, not that much; it is possible for an aged belt to stretch slightly, but not a whole inch.


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## BOSMECH

If everything is assembled right and all tight and the idler pulley is working then post a picture and then we can solve this real fast.


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## bwdbrn1

Yep, a picture, if you can post one, might be worth a thousand words.


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## indypower

A new belt will solve your problem. Even tho the belt measures the correct length, it is worn. Belts don't stretch even tho that is the term used. The sides of the belt are the important part as that is what is in contact with the pullies. The sides wear and slide further down in the pulley, thus making it appear to have stretched. If the belt is more than 3 years old, it needs replacing. And the best belt to buy is the original Toro belt.


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## airlyss

Ok guys - just took some pictures here. The first 2 are of the belt - as mentioned earlier, it looks ok and the teeth are intact, outside edges don't appear frayed. Just to note, none of the pulleys actually have teeth that correspond with the teeth on the belt - maybe the belt teeth are just to add traction.

The 2nd two pictures are of the belt installed - as you can see, even with the auger lever/tension pulley engaged, there is still a lot of play on the belt. I read the side of the belt and it is the same belt Toro specifies to use.

Thanks guys!


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## abumpa

Seems we chased this one all the way around the barn and ended up where we started. 

I would get a new belt. Make sure it is the belt recommended by the manufacture. If you are confident you can get the correct belt from a cheaper discount store go for it. If not it may cost a bit more going to the dealer but it could prevent getting the wrong one and having more problems. 

I did have a hard time with the geared pulley thing, but then I never worked on a Toro. Guess they could have used supercharger belts and pulleys on their 8000 HP models.


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## bwdbrn1

Well that definitely doesn't look right. There's no way there should be that much slack in that belt. The owner's manual describes how to adjust the tension on the auger belt.

If that doesn't do it, the another suggestion would be to take your belt to a Toro dealer, and compare it to a new one of the correct number to match your snowblower. Maybe yours got marked incorrectly.


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## bwdbrn1

Airlys, you seem to be doing a fine job of working on your snowblower, so if I can, let me use your thread to remind everyone, it's always recommended for your safety to review, and follow the owner's manual before doing any maintenance. 

Here's where to find Toro manuals.

https://lookup3.toro.com/request/request.cfm

...and refer to the parts diagrams. You can look up Toro parts by model number here.

https://lookup3.toro.com/partdex/index.cfm?xCaller=Toro&lang=us_en


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## BOSMECH

After looking at the picture with the idler pulley engaged there is no way that is the right belt. There should be tension on that belt and I see none. I presume that it is all adjusted right which it looks to be. Double check that is the right belt I would bet money it is not, also see how nice and tight your drive belt is that is how it should look when the idler pulley is engaged.


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## BOSMECH

After looking at the last picture with the idler pulley off the belt the belt should have sprung back a little bit, someone gave you the wrong belt, I don't think they are even suppose to be teethed I now my Bolens isn't but I could be wrong about the Toro.


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## airlyss

BOSMECH said:


> After looking at the picture with the idler pulley engaged there is no way that is the right belt. There should be tension on that belt and I see none. I presume that it is all adjusted right which it looks to be. Double check that is the right belt I would bet money it is not, also see how nice and tight your drive belt is that is how it should look when the idler pulley is engaged.


Thats exactly what I would have thought too - wrong belt. However, I did check the # on the side of the belt and it is 37-9080, the same one noted in the manual. I'm going to take it in right now and see what the shop says - wasn't able to do this before cause of work, but took the day off to fix this thing.

Will let you guys know the outcome - thanks again!


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## indypower

The belt is worn. Belts wear on the "V" part of the belt, where they ride in the pulley groove. The top of the belt should be even with the top of the pulley. Your pics show the belt sitting low in the pulley.


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## Ingersoll444

Well I think I see the problem. IMHO that should not have that style toothed belt on it. That is the kinda belt you find on vbelt drives on a car engine. Not for power equpiment. I would get the correct belt form the manufacturer. That will fix you up I bet.


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## airlyss

indypower said:


> The belt is worn. Belts wear on the "V" part of the belt, where they ride in the pulley groove. The top of the belt should be even with the top of the pulley. Your pics show the belt sitting low in the pulley.


indypower nailed it. Attached is a pic of the old belt on top and new belt on bottom. The old belt was worn to about 1/2 the size - it just wore so cleanly and evenly that I had no idea it was bad when looking at it.

Installed the new belt last night and the auger runs like new. Thanks guys!


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## dakota60

Glad you got it solved


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## BOSMECH

Great to hear it is fixed, because snow is coming.


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## bwdbrn1

Dang, who'd have guessed it would have worn that much! Glad to hear you've got it up and running again.


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## Ingersoll444

Great!!!!! Glad you got it up and working!!


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## rapscallion

Just a follow up to this thread. I have a similiar Toro to the OP, it's a 724 that I've had for over 25 yrs.

These blowers do not use sheer pins for protection. Even with a brand new belt, there is a certain amount of slack that will allow slipping if the auger becomes overloaded or jammed. (with tensioning pulley adjusted to it's limit)

Yet that slack still allows the machine to perform very well. Just cleared 12" of snow off our very large driveway on Monday. BTW, I've only had to change the belt once in all these years (last yr, in fact)


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