Caulking on BB hood ornament screws/nuts

[Michael J.]

I was dinged for not having caulking on my '67 BB hood underside where the "427" and trim screws/nuts protrude. My question is, does the caulking go in a strip (the way it comes in the 3M box) along the screws/nuts, or a dollop on each individual srew/nut? Thanks for any help.

[Joe L.]

Re: Caulking on BB hood ornament screws/nuts

I was dinged for not having caulking on my '67 BB hood underside where the "427" and trim screws/nuts protrude. My question is, does the caulking go in a strip (the way it comes in the 3M box) along the screws/nuts, or a dollop on each individual srew/nut? Thanks for any help.

Michael------


It was more like a small "dollop". Curiously, though, no sealer was specified in the AIM for this fastener system. It was used, though.

[Terry M.]

Re: Caulking on BB hood ornament screws/nuts

Joe,
There is no separate sealer called out in the early C3 AIMs either, yet it is there on original cars.

Just a guess on my part, but I believe the nuts came with a dollop (I'm glad you used that term. I love it. So precise and scientific. ) of sealant already applied to them.

[Michael J.]

Re: Caulking on BB hood ornament screws/nuts

Thanks for the info guys, I appreciate it as usual, especially since this info seems to be hidden from the AIM. But now that I bought a big box of this 3M caulking, know of any other places where I should look for it missing and replace it? I am assuming this stuff was used wherever it was needed to block outside moisture from getting inside something in the car.

[Wayne M.]

Re: Caulking on BB hood ornament screws/nuts

....Just a guess on my part, but I believe the nuts came with a dollop of sealant already applied to them.

Here's two small nuts I had in my bin. The color didn't come out right in the pics; the sealant is really more dark gray than **** brown .

[Terry M.]

Re: Caulking on BB hood ornament screws/nuts

Here's two small nuts I had in my bin. The color didn't come out right in the pics; the sealant is really more dark gray than **** brown .

Damn, every once in a while even the blind squirrel gets the nut. Thanks Wayne. Even though that looks a little more precise than a dollop.

[Joe L.]

Re: Caulking on BB hood ornament screws/nuts

Joe,
There is no separate sealer called out in the early C3 AIMs either, yet it is there on original cars.

Just a guess on my part, but I believe the nuts came with a dollop (I'm glad you used that term. I love it. So precise and scientific. ) of sealant already applied to them.

Terry------

That's what I thought, too. However, if the part number shown in the AIM for the nuts was the part number actually used, I can't find that it was supposed to have integral sealer. It may have but not from what I've been able to find so far.

[Ronald L.]

Re: Caulking on BB hood ornament screws/nuts

PM me when you want to endow your secret hoard of old parts

Palnut Division - TRW Mountainside NJ, I just happened to find a packet of old ones 10023709 mechanical zinc, etc on the package. What was the screw size?

[Terry M.]

Re: Caulking on BB hood ornament screws/nuts

It is a stud with no threads that is part of the emblem. The nut cuts the threads.

We will have to depend on some of the folks of the large motor persuasion for the stud size. I only know about decals and stripes on the hood.

[Joe L.]

Re: Caulking on BB hood ornament screws/nuts

It is a stud with no threads that is part of the emblem. The nut cuts the threads.

We will have to depend on some of the folks of the large motor persuasion for the stud size. I only know about decals and stripes on the hood.

Terry------


The studs for the molding are 0.166" OD and nut GM #9420272 was used for retention. As you mentioned, the nuts cut the threads in the soft, zinc-diecast studs.

The studs for the numerals were 0.133" and nut GM #9419753 was used.

All of the nuts I removed from all of the studs appeared to have some sort of sealer or caulk on them. However, it was "irregular" enough that I don't think it was a seal integral with the nut. Such a seal would have appeared very uniform.

Attached are photos of the various studs and nuts. Note that some of the nuts appear to have no sealer, at all, as what was present was "left behind" when the nut was removed. Others appear to have some remnants of sealer, but it could very well be some applied sealer that remained affixed to the nut after its removal. The nuts in Wayne's photo could be the same sort of thing.

[Terry M.]

Re: Caulking on BB hood ornament screws/nuts

Nice pictures Joe. I forgot about the molding. I could have measured that, but it is harder to see those nuts. And I would have had to take them off for the first time.

[David B.]

Re: Caulking on BB hood ornament screws/nuts

This is conjecture on my part, but I think the reason for the putty is not for weatherproofing, but was that the studs are easily broken if tightened to a point of "stretching" (it has very little tensile strength in my personal experience ). Normally, bolts are held in place by bolt friction and stretch. So, I think that the assembly line probably provided a spot fix for the problem by using putty to hold the fasteners without over-tightening and breaking the studs. Some of the assembly guys who frequent the board can probably advise if this is correct.

[Paul J.]

Re: Caulking on BB hood ornament screws/nuts

Thanks for the info guys, I appreciate it as usual, especially since this info seems to be hidden from the AIM. But now that I bought a big box of this 3M caulking, know of any other places where I should look for it missing and replace it? I am assuming this stuff was used wherever it was needed to block outside moisture from getting inside something in the car.

As I recall, most of the screws inside the door had it on them. I also found it under the windshield trim, although my windshield had been replaced.

[John H.]

Re: Caulking on BB hood ornament screws/nuts

Guys -

I spent my entire career in assembly plants, and have seen thousands of those stamped sealing Pal nuts - the sealer disc of dum-dum came as an integral part of the nut.

[Joe L.]

Re: Caulking on BB hood ornament screws/nuts

Guys -

I spent my entire career in assembly plants, and have seen thousands of those stamped sealing Pal nuts - the sealer disc of dum-dum came as an integral part of the nut.

John------


These must have been a PRODUCTION-only sort of piece. I cannot find where any Pal nuts were ever available in SERVICE from GM with this sort of sealer or caulk on them.

I have seen Pal-type nuts in the aftermarket that had an integral rubber seal. However, when installed with the seal compressed, they don't look anything like the nuts in question. With these, when the nut is installed and the seal compressed, the seal is barely visible and what is visible is very round and regular in appearance.