Keith,The published rule of thumb for drive shaft angles are;
Leaf spring 4 to 6 degrees
Ladder Bar 3 to 4 degrees
4 Link Bars 2 to 3 degrees
The thought process is that the leaf spring will windup more causing the drive
shaft to go upward. You stated that your car has an opposite the normal
condition, as it is very low and the rear is higher than the transmission
tailshaft. I believe your leaf springs ( under course loads) are flexing a lot,
giving you extreme angles. An alignment will not keep the driveshaft in the
car... controlling the flexing will. I think a ladder bar or 4 link setup is
what you need unless you car stiffen up those leafs. Bruce and John are
right...you need to keep the trans and pinion parallel at all costs !
>>> "B. Whiting" <110420.3466@compuserve.com> 06/01 4:15 PM >>>
-------------------- Begin Original Message --------------------
Message text written by John Beckett
"Keeping the transmissions and the pinion parallel to each
other.
Your adjustable suspension may need some geometry checks.
John Beckett
"
-------------------- End Original Message --------------------
John is correct on this. The angles must be the same on both the trans
output shaft and the pinion shaft. The u-joints will split the difference
for you. In over 30 years of replace u joints, etc. I've always found the
grooving to be a result of poor lubrication and not a result of
installation angles. You do want to keep the u-joint angles as low as
possible. 4 degrees works well. It's a problem of shaft whipping. The
higher the angles the more the rotational speed of the various parts of the
shaft vary from each other. Causes destruction of the shaft! Same problem
that Big 4X4's have when jacked way up. If you do have to do this sort of
thing then you need constant velocity joints like what Cadillac uses in the
big limo cars. Two u-joints on each end of the shaft. They did it for ride
comfort to the Master in the back!
Bruce A. Whiting
|