62 Inch MMM Constantly Breaking Belts - New Pulleys?

[KennyG]

Wow. Given how heavy the deck is I almost wonder if there was a manufacturing error that cracked the deck when they punched the hole. You should certainly be good now.

 

[tslbogger]

When you put washers on both sides of a plate, use different size on each side to prevent the shearing action around the washer.

 

[Captain Dirty]

You found a plausible cause and effected a working (for now) solution. mini14 suggested the solution to another possible cause--worn out sheaves. I have a 30 year old JD F510 front mower. The oem belts are kevlar "A" belts and expensive from JD. When the deck belts began to fail frequently, I measured the sheave width at the outside, thought "B" belts would be a better (and cheaper) fit, and have had reasonable success. This past season the primary (oem) belts began failing in less than 2 hours--twisted and shredded like you described. After an experienced tech rep told me the sheaves were worn out I examined mine. V-belt sheaves should have a pronounced, straight sided "V" shaped profile; mine had a "C" shaped profile that allowed the loose "A" belt to rotate (twist) and self-destruct. "B" belts work because the extra width can ride on the flanges, but the real solution will be new sheaves.

 

[daryelcorran]

How is the idler? Perpendicular to Speed Test deck, or angled so the bottom of belt is being driven towards deck? Spring tension on idler ok (no slippage when you hold blade & try to move belt)? How about the main gear box alignment?