67 Coronet driveline vibrations fixed

[Hibbing_Coronet_500]

Just to update some of you guys who might also have these issues.

I had a type beat frequency vibration at highway speeds. I messed with loose spring clamps to messing with ride height and new u joints. No cure.

I did vibration analysis on my car, because thats what I do for a living. I found that vibration to be 2X RPM of the driveshaft. Indicitive of misalignment.
I went out and bought a digital angle finder that goes to a tenth of a degree. I measured the face angle of the transmission output shaft. Then I measured the face angle of the pinion yoke. The transmission was 86.8 and the rear end was 88.7 a difference of 2.1 degrees.

I also was tired of the air shocks and ordered a new set of leaf springs. I replaced them and I noticed no pinion shims under the the spring perches. I secured all nuts and bolts. Cycled the rear suspension and rechecked my angles. I had 86.8 at the tranny and 88.8 at the rear.

I bought a set of 2 degree pinion shims. I installed them and remeasured. Both angles are the same. I test drove it and the noise is gone and I also corrected the ride height with new springs and no more air shocks.

[67r/t4speeder]

2 degree shim seems like allot, I wonder if the spring pads were relocated at some time in its life.
What spring pack did you buy ?
Glad you located problem.

[Hibbing_Coronet_500]

I bought springs from Michigan Truck Spring. http://Www.truckspring.com.
Not sure if I will like them over the long haul. The sticker had the same part number as the ones that came off and said made in Mexico.
Part number 78-539 plus 8 bushings.