Castle Nut 3774712

[Bill L.]

The nut is used in two places. Trailing arm bolts and Differential mounting bracket.

Could they originally have been two different finishes, natural and/or zinc?


Thanks, Bill

[Joe L.]

Re: Castle Nut 3774712

The nut is used in two places. Trailing arm bolts and Differential mounting bracket.

Could they originally have been two different finishes, natural and/or zinc?


Thanks, Bill

Bill------

The vast majority of slotted nuts used on Corvettes were plain (i.e. natural) finish. However, the 3774712 was an exception. It was zinc plated. However, there were actually two finishes. The older examples were ordinary zinc plated. Later examples were zinc plated with a chromate (i.e. "goldish") overplate. When did the change occur? That I don't know.

By the way, no castle nuts were used on 1963-82 Corvettes; only slotted nuts were used. Castle nuts and slotted nuts have a different configuration.

[Bill L.]

Re: Castle Nut 3774712

Bill------

The vast majority of slotted nuts used on Corvettes were plain (i.e. natural) finish. However, the 3774712 was an exception. It was zinc plated. However, there were actually two finishes. The older examples were ordinary zinc plated. Later examples were zinc plated with a chromate (i.e. "goldish") overplate. When did the change occur? That I don't know.

By the way, no castle nuts were used on 1963-82 Corvettes; only slotted nuts were used. Castle nuts and slotted nuts have a different configuration.

Thanks Joe.

I think the nuts on the lower shock mount to spindle support were zinc too.

I remember you mentioning the difference between castle and slotted nuts before.

Thank you for all your help and Happy New Year!

Bill

[Joe L.]

Re: Castle Nut 3774712

Thanks Joe.

I think the nuts on the lower shock mount to spindle support were zinc too.

Bill

Bill------


Yes, the shock mount slotted nut was the only other slotted nut used on the suspension of 63-82 Corvettes which was plated (zinc). All others (except the 3774712) were "plain" finish.

By the way, be very careful when purchasing replacement slotted nuts for Corvette suspension. Most slotted nuts originally used were GM-300-M (SAE grade 8) while a few were GM 280-M (SAE grade 5). However, most of the slotted nuts on the market today are zinc plated and of SAE grade 2 or UNGRADED. Not suitable for suspensions with critical safety-related implications.

[Bill L.]

Re: Castle Nut 3774712

Bill------


Yes, the shock mount slotted nut was the only other slotted nut used on the suspension of 63-82 Corvettes which was plated (zinc). All others (except the 3774712) were "plain" finish.

Thank Joe,

That makes it easy to remember.

Bill