72 half shaft u-bolt finish

[Patrick H.]

On the orange 72 I'm replacing the u-bolts that hold the half shafts to the differential. Were the originals natural (bare) steel, black phosphate or zinc? The replacements I just received are natural with a bit of mild surface rust, and I'm trying to figure out if I need to clean them and oil them, or treat them with black phosphate. I don't "think" they were originally zinc.

No notation in the JG, and the originals were just "rust" when I removed them.

Patrick

[Joe L.]

Re: 72 half shaft u-bolt finish

On the orange 72 I'm replacing the u-bolts that hold the half shafts to the differential. Were the originals natural (bare) steel, black phosphate or zinc? The replacements I just received are natural with a bit of mild surface rust, and I'm trying to figure out if I need to clean them and oil them, or treat them with black phosphate. I don't "think" they were originally zinc.

No notation in the JG, and the originals were just "rust" when I removed them.

Patrick

Patrick------


Originals were black phosphate.

By the way, you can still obtain the u-bolts under the original part number of GM #2066840 (for about 9 bucks, each, GM list).

[Patrick H.]

Re: 72 half shaft u-bolt finish

Patrick------


Originals were black phosphate.

By the way, you can still obtain the u-bolts under the original part number of GM #2066840 (for about 9 bucks, each, GM list).

$9 eh?
Ouch. ($5.15 + exhorbitant shipping cost at gmpartsdirect)

Easier to make these black phosphate, especially since I have other bolts to do.
Were the connecting nuts the same color?

Patrick

[Joe L.]

Re: 72 half shaft u-bolt finish

$9 eh?
Ouch. ($5.15 + exhorbitant shipping cost at gmpartsdirect)

Easier to make these black phosphate, especially since I have other bolts to do.
Were the connecting nuts the same color?

Patrick

Patrick------


The nuts had a "plain" finish. This does not necessarily mean a shiny metal. It just means that no surface finish was applied. Usually, they are sort of a gray to light brownish coloration. These nuts, GM #103026, were 3/8-24, 21/64" thick, and of GM 286M material grade (SAE grade 5).

The split lockwashers used were GM #103321. They were of 43/64" OD, 25/64" ID, and of plain finish.

Make sure you get the above just right. Future judging "trends" are going to focus on these pieces and they'll receive intense scrutiny.

[Patrick H.]

Re: 72 half shaft u-bolt finish

Patrick------


The nuts had a "plain" finish. This does not necessarily mean a shiny metal. It just means that no surface finish was applied. Usually, they are sort of a gray to light brownish coloration. These nuts, GM #103026, were 3/8-24, 21/64" thick, and of GM 286M material grade (SAE grade 5).

The split lockwashers used were GM #103321. They were of 43/64" OD, 25/64" ID, and of plain finish.

Make sure you get the above just right. Future judging "trends" are going to focus on these pieces and they'll receive intense scrutiny.

LOL!

Most of the time I'm a chassis judge, and I can't even tell what finish they're supposed to be! Often, "rust" is the correct answer just as in my case.

Thankfully this car is meant to be driven, though I suspect he may have it judged once.

Patrick