5 Ton Alternator pulley shaft sheared.

[hardimpact]

the belt I used is an auto belt 6pk1270 I would say it was 1/2 inch too long. the picture shows the belt and the duct tape around the pulley to tighten belt.

It would be a GOOD idea for EVERYBODY that has a serpentine belt engine to carry on the truck, the "short" water pump drive belt just in case the alt. shaft decides to break. Can you give the size of the short belt. ??

 

[Andyrv6av8r]

Being as I've been in your shoes with an alternator failure and my truck running hot, I just ordered 2 Dayco brands for $18 shipped for my trucks. Thanks for the information.

 

[mkupka]

I am guessing that the oe alt. is the same one used forever by the military but with a serpentine belt, the older uses had a dedicated drive belt/belts, the serpentine belt puts a LOT more load on the shaft with it driving everything, the smaller dia. shaft was fine for the dedicated drive belt BUT is to small (to much flex) to handle the load of driving everything with a single belt.

It appears that I already had separate belts for the alternator and water pump. The other belts are all intact and running just fine. There were just two small belts from the main pulley to the alternator pulley. Did the army change from a serpentine belt in one of the mid life upgrades?

 

[74M35A2]

From the pic, the short belt trick is spinning the water pump backwards. But, that is probably better than not spinning it at all. Multiple V belts were used on the Cummins NHC-250 engine. A single 8 rib serpentine belt is used on the Cummins 8.3L engine.

 

[Ford Mechanic]

the belt I used is an auto belt 6pk1270 I would say it was 1/2 inch too long. the picture shows the belt and the duct tape around the pulley to tighten belt. View attachment 607154

I would say that's one heck of a emergency fix. Good thinking in a stressful situation.

 

[hardimpact]

The belt goes around the stationary pulley(with duct tape) backwards, everything else spins in the normal direction.

From the pic, the short belt trick is spinning the water pump backwards. But, that is probably better than not spinning it at all. Multiple V belts were used on the Cummins NHC-250 engine. A single 8 rib serpentine belt is used on the Cummins 8.3L engine.