pfrederi 21,103 #1 Posted 3 hours ago Working on my neighbors 856 with 36 inch deck. They bought this machine new and it has mowed their summer property ever since. It is an old farm and the "yard" is rough and they use it to mow trails. The old girl is tired and the deck has been patched and patched up...but it still works after 60 years...But ever pivot or moving part on the deck is a bit, shall we say, worn. The current issue is the twin 3L 370 deck belts (37") (WH 1578). He got new belts but after i got them on they aren't very tight even at max adjustment. I was wondering if anyone every tried a 3L365 belt (36.5"). As you know replacing the twin belts is a bit of a PITA so before I get him to order some and I try to put them would like to know if anyone has done it. Share this post Link to post Share on other sites
ri702bill 12,937 #2 Posted 2 hours ago I for one have changed the belts on a couple of 36" gear drive decks, but used 3L370 cogged belts. And, yes, mine too were close to the end of the slotted adjustment. The center distance using the 36.50 belts would only be 1/4" shorter (1/4 off the top & bottom is the 1/2".) Should work. And yes, the captured belts are a PITA to change... Perhaps @Handy Don can shed light on this - he has had his deck apart a few times... 1 Share this post Link to post Share on other sites
Handy Don 17,399 #3 Posted 1 hour ago 10 minutes ago, ri702bill said: Perhaps @Handy Don can shed light on this - he has had his deck apart a few too many times... Fixed it 🙂 First time--general refurb and new spindle bearings (thought the original belts looked ok so I reused them) Second time--shimmed a face gear to remove gear lash (not enough) Third time--Goldilocks shims Fourth time--while mowing (at last!) one of the “looked ok” belts chunked off some rubber, so new belts. I got quite adept at this and did wonder several times why there wasn’t a stamped dimple in the deck to permit the belt to be slipped over the lower sheaves without disassembly! As I recall, the 37” belt landed in the middle of the adjustment range. Be sure to use the “why is this here” hole in the shaft that spans the mid-hitch to insert a lever rod to apply belt tension when ready to tighten the adjusting both. I did this with the deck mounted on the tractor. From my research, I learned that at one time it was possible to order “matched” belts, but that is now NLA. So I ordered four belts from a supplier that would take returns. Used the two that were closest and returned the others. BTW, the “3L” part is critical--be very sure they are ⅜”x37 so they fit properly in the lower sheaves. 3 Share this post Link to post Share on other sites
squonk 48,013 #4 Posted 1 hour ago Can you make the adjustment slot longer? Be sure to stock up on rags! Share this post Link to post Share on other sites
squonk 48,013 #5 Posted 1 hour ago (edited) Belt manufacturing has come a long way. Gates allegedly guarantees their belt to be within thousandths of an inch. So no more matched sets. You could try Napa/Gates 25-7355 which is 3/8 X 36 1/4" or a 25-7360 which is 36 5/8" Edited 1 hour ago by squonk 3 Share this post Link to post Share on other sites
ri702bill 12,937 #6 Posted 1 hour ago 28 minutes ago, squonk said: Can you make the adjustment slot longer? Be sure to stock up on rags! I recall massaging the end of the slot on one of them to be a whisker longer... 1 Share this post Link to post Share on other sites
