Hood Shaking Remedy Suggestions

[Michael A.]

I did an initial shake down drive today in my 66 Roadster and noticed the hood "shaking" as I drove along at 70mph. The "outer skin" appears to vibrate with the air flow at speed. The attached pictures show the underside of the hood. It appears that the outer skin is not bonded in any way to the x-member support on the underside of the hood.

My questions:

1. Should the outer skin of the hood be bonded in some fashion to the x-member support on the underside of the hood?
2. If so, what should be used to bond it?
3. Is there a way to do this without removing the hood?

Thanks for the help.

[David C.]

Re: Hood Shaking Remedy Suggestions

Good questions. I am interested in responses as well. My '66 BB hood does the same thing. I believe that the inner and outer would have been bonded with the original bond material. I'd like to know if anyone has had any luck squeezing some resin in there?

[Michael A.]

Re: Hood Shaking Remedy Suggestions

David
I'm trying to figure out if I should do something ahead of a planned 50000 mile trip this summer with my son. The hood has shaken for years but I've never been too concerned, assuming I would do something with it when I start a restoration, at some unforeseen date. With the long trip in about a months time, I'm working through the list of real and anticipated problems. I hope to get some confirmation as to whether or not I should do something with this and if so, what.

Cheers

[Timothy B.]

Re: Hood Shaking Remedy Suggestions

Michael,
I do not believe the hood is bonded. Someone will correct me if I am wrong but I think DUM-DUM material is used at the spots shown in your picture. I could never figure out why it's not bonded except that the bonding material might somehow show up in the hood paint.

[Gerard F.]

Re: Hood Shaking Remedy Suggestions

Mike,

Easy fix, I had the same problem with my 67 hood, bounced all over the place at speed.

Take a look at this post in the archives:

https://www.forums.ncrs.org/showthre...939#post215939

I replaced the cracked out gumdrop adhesive with 50 yr polyurethane roofing sealant/adhesive. It's black, matches the blackout, and gets like hard rubber after a day or two.

Just cleanup the frame strip area where the old stuff fell out, and apply the roofing stuff. Trim it while it is still semi-wet.

Here's mine after a short afternoon of work:



In the picture I think you can see where I replaced the gumdrop adhesive.
BTW That's original blackout on the hood just cleaned off with simple green.

Say if you get near Sonora, CA (140mi E of San Fran in the foothills)on your "California or Bust" trip, look me up. Only one with my last name in these parts.

[Eric J.]

Re: Hood Shaking Remedy Suggestions

"a planned 50000 mile trip" Is that a typo? Better pack some oil for 10 oil changes if not....

[Michael A.]

Re: Hood Shaking Remedy Suggestions

Caught me

5000 mile trip, not 50,000 mile. Although it may feel like 50,000 at the end!

Cheers

[Michael A.]

Re: Hood Shaking Remedy Suggestions

Jerry
Great suggestion. I've just added it to the list of to-do's for this weekend. I'm out chipping out the old brown stuff tonight and thinking about the plan of attack to "squirt" the new black stuff into the void.

A few questions for you:

• Did you remove the hood to do this or did you leave it installed?
• I'm considering putting some shims in place to create the space to squirt the black stuff in. By my count there are 12 points to squirt. Do you recommend doing all of the spots at one time, do one side at a time or do them individually?
• Any tricks to the cleanup?

Thanks for the offer to look you up while in CA. I just may take you up on it. Current plans have us arriving in Santa Monica on June 12 and be up in San Francisco around June 17 or 18. I'll contact you through a private message on the board later. Maybe we could meet for breakfast on the morning we start the long haul back home on I80.

Thanks again for the suggestion. It sounds like a good one.

Cheers

[Gerard F.]

Re: Hood Shaking Remedy Suggestions

A few questions for you:

• Did you remove the hood to do this or did you leave it installed?
• I'm considering putting some shims in place to create the space to squirt the black stuff in. By my count there are 12 points to squirt. Do you recommend doing all of the spots at one time, do one side at a time or do them individually?
• Any tricks to the cleanup?

Mike,

To answer your questions above:

1. I didn't take the hood off, just did it with the hood up and a screwdriver in the brace. Of course, you could do a neater job by taking the hood off and working on a flat surface. Especially if you are going to paint the underside with blackout (but you need to wait until the stuff gets to be firm rubber in 24-48 hours prior to painting).

My underside cleaned up pretty well so I opted not to paint the original blackout. With the hood in place, it was a little awkward getting the joints on the lower side of the hood frame.

2. There are 12 points to do and I didn't use any shims. Just cleaned out all the loose stuff, and applied the new stuff like you would caulk around a window. Did one side then the other side as a matter of working convenience. I did go back to each one to touch it up a second time.

If you take a close-up photo of the brown stuff before you chip it out, you could probably trim the new stuff with a razor after it hardens to make it look the same, if you want exactness. I didn't and I think it came out pretty good by just cleaning up the edges with a lacquer thinner soaked paper towel or rag.
Don't rub too hard with lacquer thinner if you want to preserve the original blackout.

3. Cleanup is with lacquer thinner, paper towels or throwaway rags. The stuff sticks to anything so you might want to wear throwaway gloves.

Have fun,

PS I think it is a good thing to do before a long trip. With the hood bouncing up and down, you tend to get longitudinal paint cracks down the central portion of the hood (like I have ) and on a long trip you will always be wondering when the hood will be flying up against the windshield (only kidding, it really can't)

[Jeffrey S.]

Re: Hood Shaking Remedy Suggestions

When I did this repair on my 66 I used 3m 5200 marine sealant ,works great ,looks like the original material ,blackish color . Hardens to a rubber like consistency and it can be removed with 5200 remover if you ever need to. Did this 5 years ago no problems no bleed thru . Hope this helps Jeff