Thanks. I have the exact same tractor. Sounds like I should source the belt and hang onto it as backup if it’s unique enough which there would be no alternate readily available. May I inquire why it needs replacing?
I started it yesterday after a break in work... heard a brief funny noise but after it sounded fine, but 10 seconds later I realized the tach read 0 as did the temperature & gas gauge - and of course the battery light was on.
Drove it up to my shop (100' away) and started looking for loose wires etc and said huh what's this supposed to be connected to? ... oh that's a belt!
The belt is a cogged v-belt and cracked aF, not surprised that it came apart. Measuring the broken belt was a false herring because it became obvious after trying a similar length belt that I wasn't measuring *all* of the belt (an inch and half or so is missing).
Before going to the store this time, I put the old belt over the pulleys and wrapped a cloth measuring tape around and got "about 42 inches".
I bought "31/64 x 41⅞" and also "42⅜" belts from the local napa dealer.
The 42⅜ was snug to get onto the pulley, but it used all of the alternator's adjustment arc to tighten it - no room to tighten it after the belt settles.
The 41⅞ was really tight to get on, but once seated in the pulleys, the alternator is at a good mid-point in the adjustment arc.
I was charged $25+tax for the belt.
Tools: 12mm to loosen alternator adjustment bolt. 14mm to loosen alternator pivot bolt, 12mm to hold nut at the other end of said bolt. I was able to slip the belts through the fan blades as the fan is notched near the housing, else I would've had to remove the fan.
Note: The OEM belt said "LA40.5". Some reading on the net told me
the “A” series belts are the most common. The number following it is the inside length in inches. The outside length
is typically 2 inches more
Assuming the ".5" means "half inch width", the LA40 would be about 40+2 inches outside measurement, which appears correct.
This is the 41⅞ that I used:
I intend to buy a spare belt (in fact, I bought two of the 42⅜ expecting that to be the correct size and only one 41⅞ so of course it was that one, but either way I have to go back - on my next trip to town, which will be perhaps my 4th or 5th this year!) - I think the old one was in terrible condition for 380hr&4yrs but maybe that's normal? Like cracks everywhere.
I find it extremely likely that the OEM belt is precisely 42", but there's no tension on the 41⅞ belt with the alternator relaxed almost against the engine, so I'm confident that it will do.