I was asked by a member of this forum about the U-Bolts used to attach the drive shaft to the differential for 64-66 V8 Mustangs. I admitted I did not know too much so I asked around, other Mustang owners, MCA judges, Mustang shop owners, etc, and it turns out I was not the only one who didn’t know that much. What complicates matters is that of the almost a dozen Mustangs I looked at, none were absolute 100 percent guaranteed original, including mine.
What I am seeking is verification of what I have listed, plus additional types, to establish guideline for use.
In any case this is what I determined:
Service part numbers (from May 75 edition Ford Car Parts):
C0DD-4529-A; used for 1964-1966 I-6 Mustangs; 1/4-28 threads (not included below).
C1AZ-4529-A; used for 1964-1966 V-8 Mustangs, 1967-1972 (to 5/1/72) all Mustangs; 5/16-24 thread, replaced by D3AZ-4529-A.
D3AZ-4529-A; used for 1972-on (from 5/1/72) all Mustangs.
From my collection, I looked at several key features and sorted them based on that. This by no means is a determination that these are the only types used, but to indicate certain differences. The collection came from 1964 thru 1973 Mustangs and from all three assembly plants, with a majority of the cars around here built in San Jose. There may be original Ford factory, Ford service and aftermarket types included.
Some definitions (mine), some obvious, some descriptive, all dimensions are in inches, no tolerances are included or implied:
Threaded legs, or shafts: the two parallel threaded portions of the “U”.
Thread size: should all be 5/16-24.
Thread length: to last full thread (approximate)
Shaft: (the portion above the threads to the top strap).
Shaft diameter: above threads.
Height: distance from end of threads to inside of strap.
Taper: (a diameter of the shaft larger than the thread size).
Taper height: start of taper if present (approximate).
Strap: top of U-Bolt that grips the bearing of the universal joint.
Strap width: maximum
Strap thickness: measured as close to but away from center if ID at top of strap is used.
Identification marking: my term, I don’t know if this is 100 percent accurate.
There are a couple of other items that cannot be measured with any accuracy, where the shaft meets the strap, the inside bend at that junction, the angle at that junction, or the inside diameter of the strap for the bearing (should be 1 1/8 inch), or the center to center of the two legs.
The pictures are of the seven types that I found with measurable differences. They are arbitrarily numbered 1 thru 7 in all pictures, from left to right, and top row to second with a piece of numbered tape for my reference. The last two have been phosphate and oil treated. Number “1” is indicated.
1 Front view: note thread length, taper, arch, and strap.
2 Top view: note marking, shaft to strap transition.
3 Side view: note thread length, taper, shaft to strap transition.
4 Measurements.
Some additional information. I found and measured a Moog U-bolt, which is a current replacement (part number 534-10) at a local Mustang shop. There was a raised “P” in a circle on the top of the strap stamped sideways as an ID.
Here are some measurements: Thread – 5/16-24; thread length – 0.809; shaft dia – 0.285; taper – none; strap width – 0.390; strap thickness – 0.265; height – 1.863. I don’t know if Moog was an original supplier and that this was their design then but this is what the current Moog U-bolt numbers are so if it is seen on your car, you know it is a Moog part.
