Hey all,

I'm replacing the alternator on my '97 F-250, 7.5L (see signature). It is a manually-tensioned belt, as the auto-tensioner takes care of the other belt (the 7.5L has two belts, unlike the 4.9).

I am using my recently-acquired FoMoCo factory shop manual (from Helm--that purchase is a saga I will relate when I have time) and when I went to look up the spec for the alt. belt tension, I got this:
Except I don't have one of those--and I'm starting to hate the word "Rotunda," as it denotes all of these FoMoCo-only tools that I don't have.

What's worse is, they don't even list the lbs. of tension for this spec., so I could at least estimate it myself.

So, even though this is a serp belt, can I use the tried-and-true (for V-belts) method of 1/2" of belt deflection, when pressed "pretty hard" with a thumb, in the middle of the longest span? I actually set it to 5/8" deflection, using this method, and it still feels looser than the auto-tensioned belt which drives the power steering, AC, etc.... But I don't want it tighter than necessary, as I don't want premature accessory bearing failures.

Thanks.

Big Six

 

The method I use for serp belts is to tighten it until, at the longest point between pulleys, I can just twist the belt through 90 degrees with my fingers. Has worked for me (so far).