throwing belts on 1966 cub low boy

S

Scott 1234

Active member
ok. ive seen some old posts on this. topic.. i am not sure i have the same mower and deck. [il put in lots of pics] have a 1966 cub lo boy. ran OK last year but started thowing belts [sorry i do not know all the terms of each part- so bear with me] . i 'think this is a C3 deck [no name plate on it] had 3 belts, but the spindles have 1 bolt each which im told is not normal for a IH] the left idler pully is older and has yellpw paint - and right one looks new. left is a deep V, and the right is not. left has wider opening than the left - one shop said the mismatch is the issue, another shop said nope. whos right? also these are 5 inch diameter, and one shop says the the c 3 was a 4 inch size? which is right? also- cant seem to get the belts to level [im told the belts right behind the pulleys heading to deck should be level with each other, but with this size pulleys i cant get them level. problem arises pretty quickly- just engage the pto, real slow and youcan see the right pullng pully flip the belt, and stays flipped into main and then left. also. honestly not sure what size belt this takes. i measured the old one that came with this unit seemed liek maybe 115? can that be right? a B115.? i see othr folks on forum talk of a B112 [regardles i keep it pretty tight on the pullys. ill see how many pics i can get in. of the back. of the left old pully and the right new pully. anyhelp apprecaited. i need to get back in to the field on the farm. :0) thanks.
 

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Scott, If you move this to the farmallcub forum you'll get more attention since this forum is for the Number Series LoBoy tractors. I will guess that your right idler pulley needs to have a deeper groove like the left one to help keep from rolling the belt. Sometimes an old belt will take a "set" and no matter what you do or try it will not behave the way it should. My experience with this situation is I'm running a B belt on a Bush Hog 412 midmount mower on my 57 LoBoy. It's very similar to what your pics show. JMHO Stan
EDIT: are you running a single belt or 3 belts? and what do you mean about the spindles have 1 bolt each? Maybe a picture of that part? TKS.
 
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staninlowerAL said:
........I will guess that your right idler pulley needs to have a deeper groove like the left one to help keep from rolling the belt........
Click to expand...
JMHO, the idler sheave that turns the belt to horizontal direction as it leaves the pto sheave should have the "deeper" vee. This might help keep the belt from rolling as well. Consider placing these 2 sheaves in that position on your mule drive if you cannot find/replace the shallow vee sheave with a deep vee type. And yeah, replace the belt also. Kevlar belts cost more but provide better, longer lasting service. Best price is on line, there's several sellers available. Stan
 
On my c3 it’s one belt so that the adjusting the pulleys will tighten the whole thing up. And I’ve run them on belts in much worse shape than that. I tightened the bolts for the pull until they start to tighten, then take a heavy hammer and gently tap the pulley down to tighten the belt and when snug I tightened the bolt down tight. But again, that’s for the single belt. Can you tell what is rubbing on the one side of the belt that shows wear?
 
I don’t remember which mower it was, but one of them has a very specific way to twist and route the belt. Be sure you are doing it the way you are supposed to or it will probably keep throwing the belt off.
 
You might also look at changing your pto pulley to the proper 6.5 inch one that is standard for the 59 inch mowers. The 8-1/4 one you have is standard for the 42 inch mowers. That will better align your pulleys.
I know….lots of folks run the big pulley, but the tractor bogs way less in heavy grass with the smaller pulley.
 
IMO the std factory supplied pulley for the C3 is 8 inches. That's what mine came with and the spare I bought also had an 8 pulley with it. Can you show me a book/manual that says otherwise.
 
from the factory it came with a 8 " rear pulley ,many run the woods type 6.5 inch pulley so the cub does not work as hard, mows fine with it, if you climb hills the smaller pulley helps, yes that belt is toast and is a B112 as long as the idler pullies are 4 " some had bigger idlers
 
Good rainy evening folks. thanks for all that info! couple points/questions: FIRSTLY 1.QUALITY OF EXISTING BELTS; i have 2 belts, orig was reg and newer Kevler. the Kevler is only about 1.5 years at best, and yeh it got chewed up fast for some reason last year [i then tried to smooth off any rough with emery on the older left one to see if tht helped] SECONDLY-LENGTH OF BELT - dang but i measured them 6 times and always came up with a different number :0) i'd say the Outside was a bit over 115 inches but maybe an inch [ could that just be stretching ?. or so.] so PETER you say a B112 is, right? i looked at the old one. hard to read [but it is made in Mexico is clear :0)]- but lookslike B111 50 but really hard to say.. But. , on the newer Kevler it looks like ; 5/8 inch X 115 B112K 50115K-- . Note; right now the left idler is Up all the way it can be [without hitting the tractor frame] .... THIRDLY -WHAT DECK IS IT; CHARACTERISTICS; Stan asked what i meant about the single bolt for blades.- so since there is no name plate on the old deck i have been told to look for IH characteristics to see if it is a IH deck and what type. - im 'told' an I H deck with 3 blades and 59 inch deck will have 3 belts AND each blade spindle will have 2 not 1 bolt holding the blade on. im told that if it has [as mine does] 1 bolt holding the blade on then that means someone over the years has chaned out the orginal IH '2 bolt' holding blade spindles with something else. true? i dont know. Finally, Stan suggested I move this chat all over to another forum here. ok. ill try - but dont want to loose you guys and your insights :0). have a good night guys. Scott in NJ
 
Scott, this is now on the Farmall Cub forum (mod must have moved it). I understand now that the blade is attached by one bolt not 2. Can't comment on what was OEM, I owned an IH 59 once but too long ago to remember the details. Also a B belt would be 5/8 inch with on top. Stan
 
It’s possible the woods supplied pulley is different than the C3 stock pulley. Woods calls out the 6.5 inch in their books.
I also run my mule drive vertical, not tilted. (Works and too lazy to change)
Level your pullies…left one is too high. Look at changing to the cast pullies from the stamped ones. (4116 iirc).
The mismatch between the 8 inch and the idlers tends to climb the idlers as the belt twists.
Once a belt rolls and jumps, best to just throw it out. My cheap belts on my woods 59s do just fine. (They have a 3/4 twist on the return).
Is your belt tight enough? Should be banjo string tight with the deck up, and it will get tighter when you drop it to mowing position.
 
In the first post of this thread, picture 7041 shows the mule drive on this LoBoy sits at an angle rather than vertical to the pto. Some of the advice about adjusting the idlers height seem maybe to be directed to a mule drive that sits vertical to the pto (maybe a FCub?).............so I'm wondering if this particular mower might be different? So much can (and does) get changed over time that it's hard to know what is correct!! On my 57 LoBoy with a FH, I'm using a Pennington mule drive (vertical to the pto) with a Bush Hog 412 42 inch cut mower and it fits and works very well. So the question is, what is the correct OEM mule drive for this particular mower?
 

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I recommend Hamilton Bob’s for C3 belts…..yes you will need 3 belts and I also recommend downloading the Danco C-3 mower manual from the server for an accurate setup. The C-3 is a great mower but it does need to be set up properly.

Note: I know for a fact that mounted on a Standard Cub the idler pulley are not exactly the same height….one is slightly higher than the other but I don’t have the information in front of me presenting that is why I highly recommend reading the manual.

NJ Farmer
 
Hi,
Below is the IH C-3 Mower operator's manual, made in 1965, it says. It has lots of info. I would read it and see if you find something that needs correction on your mower.
The manual is for use for putting C-3 mowers on 3 different models of IH tractors.
The setting up instructions for use on the LoBoy go to page 9.
You have to download the manual to see it. The download button is at the upper right of the page in the link. :)
 
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Thanks folks. ; first thing monday ill call Junior at Hamilton and see about getting a new B 112 Kevler belt. for it.. and also look in to the manual for the C-3 deck. [side note; yes, the Mule is at an angle-was made that way i think- and no the belts are not all that tight inthe photo. but I will make them banjo tight as You suggested-- and also. im glad you {NJ Farmer] said the idlers are not to be teh same hight when on angle main pulley- there really is no way to do it- you cant raise the left one up anymore due to the tractor block.and the right one really cant budge too much down as the belt gets tight-the result with uneven idlers is teh belts come in and leave and different leverls but that seems to be the way it is. ] OH , washer!- did imention - to get it going the other day - before the rain- i swithed it to 5 washers on the left pushing the left idler out far, and only 2 onthe right -keeping that idler hugging the hanger.- that seems to have helped the alignement- ony thing is i have to watch theleft nut. making sure it has enough threads to hold on :0) thanks .. off to Hamilton Bobs in monday morning. Scott G
 
I don't have experience with that model mower. But I think I would go with the belt much looser than has been suggested. It should stay on without being excessively tight if the pulleys are properly aligned. The pulleys need to be set so the belt runs straight onto and off of each pulley. However, alignment is much more critical as the belt goes onto each pulley than as it comes off the pulley. Leave some misalignment as the belt comes off the pulley if you need to in order to have perfect alignment going on. Do this adjustment with the deck down in the mowing position.

Measure the center-to-center distance between the 2 mule drive pulleys, measured along a line perpendicular to the pulleys. That measurement will probably be the diameter of the PTO pulley that will work best for keeping the belt on.
 
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