Snow Model 551 CC Snow Blower

[kruss77]

Model 551 CC Snow Blower Drive Belt Problem

I just burned through my second drive belt on my model 551 snow blower. The first belt lasted 7 years, then snapped last week (it looked old). I bought a CC brand replacement belt and it snapped in 1 hour. While installing the new belt this morning I made sure that everything was moving freely in case the first failure was triggered by something getting bound up. Everything moved freely and the new belt (other than being a little stiff -as I would expect a brand new belt to be) went on fine. However, after only about an hour this morning, bang! It snapped in half and was separating in two other spots. This particular application requires the belt to twist 90* in a span of about 9" on either side the blower housing as the belt transistions from the blower drive pulley onto two idler pulleys as it twists 90* again again as it transitions on up to the main drive pulley on the front of the motor. That seems pretty severe for a stiff belt like this, but the last belt lasted a long time with no trouble traveling that route. I wonder if the new belt was TOO stiff.

Anyone got any ideas? Is there a superior brand of belt I should be using or did I do something wrong?

Also, anyone ever hear of a steel or kevlar reinforced drive belt?

 

[rcbe]

Re: Model 551 CC Snow Blower Drive Belt Problem

yeah, CC uses belts made from kevlar in a number of apps on their products. Dunno if yers is supposed to be such or not

Looking at CC's current parts list for your blower, you should have gotten a "754-0341 V-Belt, 5/8 X 89 Lg", right ?

 

[kruss77]

Yeah, that's the part number I ordered, except when I picked it up the package was labeled 954-0341. I was told that '954' was the correct number.

 

[rcbe]

I would question yer belt source closely on thet p/n difference - the number I referenced wus right out of the current cub parts list for thet blower. You may have gotten a substitute belt w/o the kevlar construction.
Did the pkging on the belt you just picked up have cub cadet or MTD logo labeling on the box/wrapper ?

 

[kruss77]

I questioned the number when they (the CC dealer) told me there was a replacement number, but they claimed it was the "new" number for this part. Is there a way to determine if this belt is actually Kevlar reinforced? If it is, I'm in trouble since I've now broken two of them.

Do belts need to be 'broken-in' or seasoned somehow? Perhaps I went at it too hard right out of the gate. The temperature outside yesterday was right at 32* and the snow was somewhat heavy and wet. It broke while I was attempting to clear a particularly deep section of snow at the road where the plows heap snow into the end of the driveway (with all the slush from the road mixed in with the snow). I've cleared that section plenty of times without any problems, but this is the same spot I lost both belts. Also, I'm wondering if the spring that tensions one of the idler pulleys is too weak. It doesn't seem to place much tension on the belt. After re-inspecting both belts last night I noticed that both had a 'burn' mark on half of the back side of the belt all the way around. I wonder if the belts rolled over and lost their grip until they finally snapped.

Attached is the sleeve and label for this belt.

 

[rcbe]

Ken - get the phone number to CC corp service dept anf have them to confirm correct part number and if belt construction is/should be kevlar. phone Number should be in your manuals. If you can't find, try this number: 1-877-282- 8684

Make SURE your belt path is working good - idler pullys, brgs, pivot points dry lubed, etc. Your comment about failed belts being burned on back is a tip that all is not right with your belt path. Consult yer manual for any help on routing correct side of belt around "90 degree" idler pulleys - or ask CC serv tech during phone call.

When belt is installed and depressed at middle of belt span between 2 pulleys (mebbe 6-8 inches) with yer index finger - belt should not easily depress more than 1/4 inch, IMHO. If more, would suspect idle brkt spring is installed wrong or too weak.

I don't think any "special" belt break-in is needed outside of engaging blower drive and running for a minnit or so to get belt warm, flexible and fully seated before sugjecting it to heavy loads.

 

[kruss77]

I'm going to pick up a Kevlar v-belt from Tractor Supply this week and try it as an experiment. TC claims their Kelvar belts are for heavy duty applications so I'm going to see what happens (it'll be easier to ruin a $25 belt vs. the $40 CC belt). I'm also going to pick up some HEAVY DUTY tensioning springs to try on the idler pulley lever. There was definately more than 1/4" of play in the belt with the tensioning arm set. I'd guess that it was more like 1.25". It did seem intuitively looser than it should have been, but I didn't consciously think about increaseing the tension since it'd been fine up until now (well, maybe not 'fine' since I've lost two belts within a week!). It seems to me that that might actually be the problem since both belts failed in the exact same way and both had the exact same 'burn' marks on the backside of the belt suggesting that they rolled over on the pulley. I do recall the belt rolling over two seasons ago (I smelled the belt burning and immedaitely stopped and inspected -only to find it on its edge). However, it worked fine the rest of the season and up-until last week. Perhaps the tensioning spring has 'relaxed' over time and is in need to replacement (it is 15 years old now).

 

[7254t]

99 percent of belts that started with 754 are now 954. Same belt last numbers are the same.

 

[MUD&GRASS]

the one thing about generic belts, kevlar included is that a lot of times they don't have the reinforcement for back side idlers and don't last.
the comment of burnt areas tell me that something isn't moving.
my experince is that a broken or burnt belt is a symptom of a problem, not the problem itself

 

[kruss77]

Well, I was able to confirm that the CC replacement belt I ordered/ruined was indeed a Kevlar reinforced belt. CrapDamnit! That explains the cost ($40.00). I'm still going to buy a no-name Kevlar belt to use for experimenting with the idler pulley tension. At least if I ruin it it'll only cost me half as much! Once I get the idler pulley tension dialed in, I'll order another CC Kevlar reinforced belt. We'll see how it goes!

 

[VinceSMTA]

I think Mud&Grass has some good advice. If there are burn marks on the belt it probably means that something is freezing during operation while the belt continues to turn. From my experience, sometimes it takes a fresh set of eyes to look at it to make sure all is fine...so go buy some beer and invite a mechanically inclined friend over.

 

[rcbe]

Ken - just another thought... that gearbox - is it properly lubed? ck yer manual for any specs on that and then the box's lube condition. If it's poorly lubed, may wanna seize up when under heavy load and heating up... such could quickly burn a belt and then cool right back down before you got the tractor back in the garage... long shot, mebbe - but worth a look.

 

[kruss77]

If there are burn marks on the belt it probably means that something is freezing during operation.

I suspected that too. But everything moves freely and is in correct alignment. The "burn" mark is really just a discoloration of half the backside (non 'V' side) of the belt running the entire outside diameter of the belt. I saw this same thing before when my original belt rolled over on edge a couple of years back. (In that instance, I stopped the blower before the belt was damaged.) My suspicion is that the tensioning spring on the idler pulley has relaxed over time and does not maintain proper belt tension under heavy loads anymore (I lost both belts during heavy snow removal). With such a stiff belt, this could allow the belt to roll over as it tries to twist 90* from one pulley to the next. If that is true, the discoloration on the back of the belt would be caused by friction (as the belt is now riding on edge and not gripping properly) as the backside surface is dragged against the pulley groove. This would also result in a loss of power on the blower without a corresponding loss of engine power (which is what I experienced) as the belt loses its grip on the drive pulley as a result of riding on edge. That makes the most sense to me based upon the evidence. I'll know for sure after I re-tension the idler pulley with a replacement spring and run it again.

... that gearbox - is it properly lubed? ck yer manual for any specs on that and then the box's lube condition.

Suspected that too, but it is permanently sealed and can not be lubricated by the user. Now, that doesn't beam it's not the problem, but it wasn't even warm to the touch when I lost the belt (I had initially thought I hit something with the auger and lost a shear pin, so while inspecting the blades I touched the gearbox and it was cool).

I'll know more after my idler pulley tensioning experiment (which I suspect is the real culprit).

 

[kruss77]

OK, I picked up both an aftermarket Kevlar belt and another CC OEM Kevlar belt. The aftermarket belt (from Tractor Supply) is shown in the photo below. This is the belt I'll be using to test the improved idler pully spring tension rather than risking the more expensive OEM belt. If the aftermarket belt works with the new idler pully spring, I might just keep using it instead of swapping-out for CC belt. In the other photo attached below, the new spring for the idler pulley is on the right . The original OEM spring is on the left.

I'll be installing everything later today and will post pictures once installed.

 

[rcbe]

lookin good - keep us posted.

 

[jimdiesel1]

I had a similar problem, found out why....check the bolt/strap in the auger housing that supports the auger and gearbox. Mine was missing, which allows the auger assembly to drop more under load, since the big pulley for that belt is on the same shaft it would misalign badly. In fact it broke the mounting ears off of the gearbox ahead of that large pulley! I looked for problems for awhile before I noticed, it is easy to overlook.

Since I replaced the supporting bolt through the strap that supports the auger unit (drops from the top of the auger housing to the auger gearbox) I have never had additional problems. It is a fine snowblower in my opinion.

 

[kruss77]

I had a similar problem, found out why....check the bolt/strap in the auger housing that supports the auger and gearbox. Mine was missing, which allows the auger assembly to drop more under load, since the big pulley for that belt is on the same shaft it would misalign badly. In fact it broke the mounting ears off of the gearbox ahead of that large pulley! I looked for problems for awhile before I noticed, it is easy to overlook.

Since I replaced the supporting bolt through the strap that supports the auger unit (drops from the top of the auger housing to the auger gearbox) I have never had additional problems. It is a fine snowblower in my opinion.

Thanks. I'll check that out when I get back to it. It's been over 50* for the last two weeks here in south-eastern Michigan and all of our snow is gone, so there's been little urgency for me to get this wrapped-up. I had to use the tractor for something else yesterday and took the blower off it to make that task easier, so it'll be easier to inspect for those things you've mentioned with the blower off the tractor. I might be able to get back to it this weekend. I'll inspect it thoroughly and report back what I find.

Thanks.

 

[kruss77]

Well, I found part of the problem: sometime this season (probably when the first belt let go) the moveable idler pulley arm got bent -meaning that the pulley itself is no longer aligned with the main drive pulley on the blower. This is particularly important because there is only a short distance between It's bent about 1.25" board making it impossible for the belt to remain on the idler pulley with the PTO engaged. I couldn't see the misalignment with the blower on the tractor (which explains why I lost the second belt so quickly after replacing it -the blower was still on the tractor when I replaced the belt) and it only became apparent what the problem was after glancing at the blower from this perspective. This idler pulley swivels freely around its pivot bolt and can contact the ground without a belt on it. I remember the pulley getting pinched under the tractor when I lost the belt earlier this season and that's probably when the idler arm got bent (shame on me for not assuming an 800lb tractor MIGHT bend a 3/16" thick piece of metal -and conducting a more thorough inspection at that time). Regardless, this may make my theory about the idler pulley spring baseless, but I'll probably go ahead and install the heavier spring anyway. I guess it can't hurt at this point!

 

[kruss77]

This was my 'fix' for this problem:

The root cause of my problem was indeed the bent idler pulley bracket. Knowing that this type of failure was likely to happen again over time, I welded a small length of angle iron to the idler pully arm to prevent it from bending again (even under the weight of the blower). That solved my problem.