`69 Half-Shaft Bolt Head Markings

[Michael I.]

I'm replacing the U-joints in our recently acquired `69 big block. In taking things apart I found that all of the bolts securing the U-joints to the differential yokes are 9/16" head with an "A" marking and three radial lines, which I assume to be correct. At the outer U-joints, I found a mixed bag. On one side, all the bolts are 5/8" with a head marking "BIS" where the I is taller and the B and S are nestled into the I, plus grade markings around the perimeter. On the other side I found three bolts with 5/8" heads with a head marking that looks like two elipses laid at 90 degrees to one another with the letters "B" and "P" in one elipse. The other bolt has a 3/4" head which I'm sure is wrong. In any case, if anyone can tell me what the correct bolt head sizes and markings should be and where they might be obtained I would very much appreciate it.

[Joe L.]

Re: `69 Half-Shaft Bolt Head Markings

I'm replacing the U-joints in our recently acquired `69 big block. In taking things apart I found that all of the bolts securing the U-joints to the differential yokes are 9/16" head with an "A" marking and three radial lines, which I assume to be correct. At the outer U-joints, I found a mixed bag. On one side, all the bolts are 5/8" with a head marking "BIS" where the I is taller and the B and S are nestled into the I, plus grade markings around the perimeter. On the other side I found three bolts with 5/8" heads with a head marking that looks like two elipses laid at 90 degrees to one another with the letters "B" and "P" in one elipse. The other bolt has a 3/4" head which I'm sure is wrong. In any case, if anyone can tell me what the correct bolt head sizes and markings should be and where they might be obtained I would very much appreciate it.

Michael------

As far as the differential yoke u-joint cap bolts are concerned, the ones you have are common for that application (but not necessarily the only headmarking used).

The outer u-joint flange bolts are SAE grade 8 (6 radial lines), 7/16-20 X 1-1/8". These have a 5/8" across-the-flats head. They are phosphate-organic finished. The most common ones I've seen have an "O" in the center as a headmarking. However, this is not necessarily the only headmarking used. The Paragon reproductions are exactly identical to the original bolts installed on my original owner 1969.

[Michael I.]

Re: `69 Half-Shaft Bolt Head Markings

Thanks Joe