Quote:
> Since you have some shafts, perhaps I could impose upon you to take some measurements. There would be no useful numbers on the joint itself. If I had measurements of the u-joint, I could ID them from that. These are best done with a set of vernier calipers, but if you have a finely graduated ruler, it could probably get me close enough to determine which u-joint. Here are the measurements I need.
1) Measure the u-joint cap diameter as closely as you can.
2) Measure the distance from cap to cap (directly across) as closely as you can.
3)If you happen to have a u-joint apart, measure the diameter of the u-joint trunnion.
Also, if you have time and the vernier calipers, could you measure a couple of other things on the axle shafts?
1) Does the inner shaft taper down to the 30-spline section, or is it fairly uniform in size. If it tapers, please measure the thicker part of the shaft (below that really thick part right below the yoke).
(my reply)
The inner shaft is 1.31 inch...that was verified by several members in the past. It is 30 spline. There is no taper other than the fairly quick reduction from the yoke.
(end reply)
2) Measure the outer axle diameter inside (at the bottom of) the splines.
This is the minor spline diameter and this will help me verify the number I have for 21 spline shafts (assuming it's 21 spline, that is.
(my reply)
Outer end number of splines=21
Diameter of outer shaft at outside of splines=1 23/64....1.359375 This
is the diameter of the splines themselves...they are wider than the shaft they are on.
Diameter of outer shaft away from splines 1 1/4 inch exactly...1.25. This is the diameter of the shaft between the joint yoke and the splines, no taper.
On the joint question...here are the measures I have:
Snap Ring Dimension aka outside of snap ring groove to outside of opposite snap ring groove: 3 inches even
Diameter of cap inside of snap ring 1 3/8...1.375 Outside of the yoke the cap has a tapered edge that seems to measure 1/32 of an inch smaller then the 1 3/8...dont know if that means something.
cap to cap, outside: 4 11/64...4.171875
Ujoint body, the large rough center part:: 2 inch even
Machined surface between bearing cap and rough finish center body: half way between 9/64 and 10/64 by eye....19/128ths best guess...0.1484375
Cap Length, end to end: 15/16ths inch
2 inch body + 2- 9.5/64th (19/64) sections between body and caps + 2-15/16ths (120/64) caps = 4 11/64
(end reply)
His Reply to all that:
Quote:
These measurements sinched the deal and I know what is what now. Thanks so much!
It's a very odd combination of parts. The inner axle is about the size of a common Dana 44 of today, though bigger than the Dana 44 of the era in which the axle was built (most D44s of that era were 19 spline). The outer shaft is the same as was used in the Dana 70 axles of that era. The U-joint measures out to be a beefy 1480 series u-joint, most likely a 5-88x Spicer. This is a common joint used in closed knuckle Dana 70s to the mid 1970s and similar to the 5-332x size used in the open knuckle Dana 60 fronts used from
the late '70s until today.
Internally, the M-715 axle is similar to the Dana 60s use the the front axles of some high GVW Ford F-250s and F-350s in the '74-76 Ford, though the Fords had much smaller u-joints and smaller outer shafts. In '77, the Dana 60 fronts went to the more familiar and much more beefy 1.5-inch, 35-spline inner axle and 1.31-inch, 30-spline outer shaft. The Ford units mentioned earlier are known as the "Wimpy-Sixties" because of their small axle shaft dimensions and small axle u-joints.
The way I see it, the inner axle is the main weakness of the M-715 D60, and I presume that's where they break most often. It might be possible to substitute a more modern 35-spline Dana 60 inner shaft, perhaps a blank axle cut to the right dimension and resplined. You'd have to then install a 35-spline carrier (perhaps a Powr-Lok) or at least 35-spline side gears. Without all the parts laying here to compare, it's hard to say just what could be done, but it's likely there are a number of other "mix-n-match" improvements that could be made internally without changing the exterior look.