belt deflection

[towpainter3]

The a/c belt on my Scout 2[345 sv] Is deflecting or vibrating to the point its making contact with the fan blade. It doesnt do this all the time. But does do it frequently.
The belt runs from the water pump to the a/c compressor only. Im running an a50 dayco checkmate belt and its tight to the point I have no more adjustment.
According to the parts store the belt should be 53in long but I dont see how.
Anyone have any suggestions. I dont want this thing to catch real good and cause a major malfunction. The pulleys are in line and the compressor is new,and seems to operate smoothly.

 

[RobG]

I see it as one of two things, the belt is too loose or is the wrong cross section for the sheaves. If you cannot tighten the belt any more it sounds like it's too long. You should have some adjustment left once tightened. When you push on the belt you should get about 5/8 inch deflection.

Rob gimmel

 

[towpainter3]

Went with an ap49 belt, im using industrial type belts due to the heavy construction and the major thing they are free!!!! The pulleys on these things are deep and seem to be forgiving in some fashions and not in others.
So far the deflection has decreased and I still have over half of the adjustment left. I had to roll the belt on the pulley but thats the way these belts are designed according to the old man at the electric motor shop we use . He said that carlisle ,dayco and the other industrial belt mfg determined many years ago that service guys dont loosen bolts they just roll them back on. Lol, so they compensated. Maybe bullshit May not be but it worked