Quote:
Originally Posted by Eturnit3
Im trying to find any info on proper way to set pinion angle. Im swapping in a 14bff into a half ton 72 long box on about 4" lift running 350-sm326-205 if its relevent. I need to know:
What surface should my angle finder should be measuring from (the face of the yoke?)?
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Along the pinion centerline. You can approximate this by putting something in the u joint cup and setting your angle gage on that - or - by going perpendicular off the face of the pinion (where the u joint straps mount) - or - sometimes that casting flange on the case is a good approximation.
Quote:
Originally Posted by Eturnit3
What should the angle be relative to? the ground? the yoke at the transfer case? the driveline?
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Not the ground. You are interested in the working angle formed by the two components.
Quote:
Originally Posted by Eturnit3
Is the slope my truck is resting on, a problem in determining proper pinion angle? What do I need to take into consideration if so?
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Nope - the working angles would be the same if the truck was upside down or on it's side ( it would just be harder to measure) because you are going to subtract the angle of one thing (like the driveshaft) from the angle of the other (like the pinion).
Quote:
Originally Posted by Eturnit3
Is the a General ideal angle?
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For leaf springs I think it's like 3 - 7 degrees, so that as the pinion winds up during acceleration the angle tends to straighten out.
Quote:
Originally Posted by Eturnit3
Thats about all... oh, one more. Its my understanding this measurement is to be taken at ride height? does it matter?
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Yep. Do it at ride height.
See if any of this helps:
Quote:
Originally Posted by Keith Seymore
What you are really interested in is the "U joint working angle". You want to know the angle the U joint sees.
Therefore, it's the difference between the raw angle of the drive shaft and the raw angle rear axle pinion nose.
I've never said this publicly before but - ideally you would want that to be straight (ie, zero) EXCEPT then the u joint would brinnell the rollers into the cap and either make noise or cause a failure.
Fortunately, it's never going to end up straight anyway, because of the static angles required to make the connections and because of the dynamic changes in angle due to load under accel/decel.
Having said all that: for a "four link" car (ie, not leaf spring) I'd want the rear u joint working angle to be between one and three degrees, and ideally would want it to cancel out with the front (trans/prop) u joint working angle.
To answer your question specifically: assuming the drive shaft is angled 5 degrees down (as you follow it towards the axle), then the pinion nose of the rear axle should be 3 degrees up, giving a difference of 2 degrees.
My $.03.
K
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