MTD Cub Cadet 42 inch deck belt size

[Mower King]

Maybe we need to step back and look at it differently..........
Sorry about the crude graphics, but it was just easier for me...

View attachment 53382

I see someone went to the same Arts and Drafting Class I did!

 

[bertsmobile1]

OK.
Now that I have seen it fully tensioned , I am of two minds.
That belt looks quite tight and the spring looks like it has good tension on it so moving the spring is not going to shift the pulley position very far.
So it looks like I may have been wrong & Fish may have been right, your deck might need a longer belt
Most of the ones I service the hole you have the pen at is in the groove in the deck so the spring slips into it .
Only one has the anchor bolt like your deck & it has a shorter spring
This deck was in production for near 20 years so there were a few variations to the layout.
And because Cub was originally pat of International tractors, the decks are considered as a separate item to the mower so have their own individual parts lists.
So you might need the 66.9" 954-0645 belt that Fish suggested and then move the spring back.
Always a problem with old decks where lots or wrong parts will fit.
'For all we know the tension arm itself may be too long & from a different deck.
Usually the contact arc on a drive pulley would be 1/2 the circumference and in your shot it looks around 1/4 so would be highly prone to slip.
In the running position the tension pulley is just about in line with the drive pulley .
On the left side frame rail should be the ID tag for the mower & the deck should also have an ID tag with a number on it.
Unfortunately the tensioning lever usually rubs on it and wears through the number.
IF they are there then the numbers might help to sort things out better.

 

[StarTech]

It looks like you would be good once the deck is on the mower as the drive pulley will have more tension on it (moving toward the front of the deck) so it will cause the idler to move back toward the center of the deck a little then it is currently positioned.

 

[Homefield]

It looks like you would be good once the deck is on the mower as the drive pulley will have more tension on it (moving toward the front of the deck) so it will cause the idler to move back toward the center of the deck a little then it is currently positioned.

Unfortunately that is he problem when the deck is in position and the pto drive attached, there is slip when cutting, when I put all new belts on it was fine for a couple of cuts but as soon as the belts bedded in it now slips as soon as I'm cutting.

 

[Homefield]

OK.
Now that I have seen it fully tensioned , I am of two minds.
That belt looks quite tight and the spring looks like it has good tension on it so moving the spring is not going to shift the pulley position very far.
So it looks like I may have been wrong & Fish may have been right, your deck might need a longer belt
Most of the ones I service the hole you have the pen at is in the groove in the deck so the spring slips into it .
Only one has the anchor bolt like your deck & it has a shorter spring
This deck was in production for near 20 years so there were a few variations to the layout.
And because Cub was originally pat of International tractors, the decks are considered as a separate item to the mower so have their own individual parts lists.
So you might need the 66.9" 954-0645 belt that Fish suggested and then move the spring back.
Always a problem with old decks where lots or wrong parts will fit.
'For all we know the tension arm itself may be too long & from a different deck.
Usually the contact arc on a drive pulley would be 1/2 the circumference and in your shot it looks around 1/4 so would be highly prone to slip.
In the running position the tension pulley is just about in line with the drive pulley .
On the left side frame rail should be the ID tag for the mower & the deck should also have an ID tag with a number on it.
Unfortunately the tensioning lever usually rubs on it and wears through the number.
IF they are there then the numbers might help to sort things out better.

Unfortunately as you correctly said there is now no ID tag

 

[Homefield]

Update. I have relocated the spring anchor point to the point just in front of the deck suspension point (where the pen is pointing to, in one of my earlier posts). There was a hole in the top plate but not through the deck. So I drilled a through hole and installed a bolt. I spent about 1hr mowing and there was no slip and all worked well even in longish grass.
So thank you very much for all you time and opinions on the issue which seems to have cured the issue it seems the belt just required slightly more tension which is what relocating the spring achieved. I shall now continue to monitor this site to see if I can be of any assistance to other MTD Cub Cadet users. Thank you again