So how do you set the pinion bearing preload properly? I am on the fence about if I should get the new flange or an adapter. If changing the adapter is as easy as the writeup I would have no problem but I've never torn down an entire diff on my own.

 

Not speaking for Brian or Shaftmasters, but I believe torqueing the pinion nut to 140 lbs-ft sets the preload.

 

I've been reading that you need a new crush sleeve to know how far to tighten.

 

To do it by the book, you're probably right.
Others who swapped pinion flanges (only) have to chime in with their input.

 

I'll wait for some more input but I'm feeling like I may go the way you did.

 

Here's how my 82 GMC service manual changes a pinion flange, dust deflector and/or oil seal.
Remove brake drums (old book) and wheels. (Remove rear disc brake pads or at least make sure they're not dragging on the axle rotors). Remove drive-shaft from yoke. Measure the torque required to rotate the pinion with a beam or dial torque wrench.
Scribe a line down pinion stem, pinion nut, and flange to aid on reinstallation. Count the number of exposed threads on pinion stem. Remove flange.
If you're not reinstalling the original flange I guess the thread counts taken earlier won't be accurate unless the new flange has the same exact depth measurement. However what they want in the end is to retighten the flange nut so you have the same flange rotation torque as measured previously. Then tighten the nut in small increments until the torque necessary to rotate the pinion exceeds the original figure by 1-5 in.lbs. Do not exceed the original torque by more than 5 in.lbs.

I know, I didn't use a Ford service manual... Hope this helps

 

[quote=Lime GT;5528242]Here's how my 82 GMC service manual changes a pinion flange, dust deflector and/or oil seal.
Remove brake drums (old book) and wheels. (Remove rear disc brake pads or at least make sure they're not dragging on the axle rotors). Remove drive-shaft from yoke. Measure the torque required to rotate the pinion with a beam or dial torque wrench.
Scribe a line down pinion stem, pinion nut, and flange to aid on reinstallation. Count the number of exposed threads on pinion stem. Remove flange.
If you're not reinstalling the original flange I guess the thread counts taken earlier won't be accurate unless the new flange has the same exact depth measurement. However what they want in the end is to retighten the flange nut so you have the same flange rotation torque as measured previously. Then tighten the nut in small increments until the torque necessary to rotate the pinion exceeds the original figure by 1-5 in.lbs. Do not exceed the original torque by more than 5 in.lbs.

I know, I didn't use a Ford service manual... Hope this helps[/quote
Good information. I have measured the length thru hole(depth) on both the OEM flange and the replacement flange, they measure the same. So counting threads should work as a good point of reference.

 

Counting threads and realigning the scribe marks should bring you back to original torque as long as the flange depths are exact. What I normally do when changing pinion seals ,using same pinion flange, is to retighten nut to original scribe marks and then tighten the nut just enough so it's scribe line is slightly past the flange's scribe line by the width of the scribe (about 1/64th inch).

 

I just looked this up in the Ford manual and it say pretty much the same thing.

 

What was the part number for that flange and where did u get it

 

Available from Ford.