Farmall Cub

my cub just started throwing belts, I had no problems last year. I have a c3 rotary mower, using b112 belts. This year I cannot keep a belt on for more than 5 minutes. Looking a the rear idler pulleys, they don't even line up straight with the center pulley on the mower. Idlers are fixed (can go up and down) but they really need to angle left or right. As I watch the belt when the PTO is engaged, it looks like the left idler rolls the belt and the center pulley throws it off. Any suggestions to fix this, last year no problems, this year-frustrated..

G'day to you. Sorry to hear you have problems keeping the belts on your C-3. Here is the manual for it - C-3 Rotary Mower 12-20-63

Will this help?



We have a lot of resources for our members and I would suggest that you might want to spend a little time following the links below.

to Farmallcub.com Forum Family. And you have come to the right place for all things Cub related. If you click on the Site Rules, Regulations, & Important Information, it will point you to the Welcome Wagon wherein you will find links to many useful sites and topics. One of the most important resources are Owner's Manuals, Parts Catalogs and Service Manuals. The Cub Manual Server is the home of the jpg versions and the [url=http://www.farmallcub.com/[ Sorry, direct links to manual section is not allowed. ]/index.php]PDF Manuals[/url] -- well the pdf's of course Enjoy!.

Welcome to the forum from Arkansas. Use my C-2 very little, but I know it has to have the right belt and a good quality belt and be adjust right. There are some folks on here that know them inside out, but welcome.

Once the belt breaks the cord on the inside they will not stay on.

Have you tried a new belt?

Did you remove the mower for the winter, then reinstall it? Perhaps you reinstalled something incorrectly?

Does this look familiar?

Thanks for the quick replies. New belt being used, B112
haven't taken the mower off.
The rear end has the pto, and two idler pulleys below , fixed, can go up and down, but off set at an angle.
I haven't had any problems changing a belt before and this us now my third belt

Are the pulleys rusty or scored? What brand belt? Same as last year or different?

Okay, if you have a new belt you should have had to move the pulleys to install it. More than likely, you just have an alignment problem. Take a piece of string or a straight edge long enough to reach the idler from the drive pulley. Pull it flat down the face or side of the drive pulley and it should fall into the sheave of the idler. If the pulleys are not aligned all the new belts in the county won't stay on.

Thanks for the replies. I put on an older belt and have the best luck so far. Today it finally is done. None of the new B112 belts stay on. I only had to move the idler pulley up to get the belt off. Attached photo on the back/pto. The idler pulley go down the left of the tractor but the mower pulley is in the middle. Last year, no issues with belts staying on, this year can't mow. Any help appreciated. Thanks.

Check a few alignments. From drive pulley on PTO to idler pulleys, belt should be perfectly vertical. If not, adjust drive pulley on PTO shaft to make it vertical. From idler pulleys on mule drive to canter pulley on deck, belts should be as close to horizontal as possible, and as close to in one plane (together) as possible. Don't let one pulley run much lower than the other. If alignment is correct, then be sure all pulleys turn free with no wobble. Also be sure none of the pulley lips (sheaves) are broken or worn. After that, the only problem remaining is the belt.

Had the same problem awhile back.....The PO had a notched belt as a main belt and when it broke I replaced it with a b112....Off they came ( I tried several)....Then I looked at the manual and noticed the main belt went to the top notch on the pulley on the mower(at least in the manual , I looked at) and not the center notch as the PO had put it on....Put a Kelvar b112 and ran it to the top notch and ....problem solved....Been a year now with no problems.....That just my experience...Worked for me....Dave

What condition are the bearings and hubs on the deck, particularly the center one? Not that it matters but is that an A you're working on? The draw bar set up looks different than a Cub.