Does anyone have any experience with the oil-canning affect of this huge hood going down the road? I have adjust the rubber hood adjusters, they seem to be fine, however, the left and right sections of the hood seem to quiver going down the road. No rotational vibration from drive train, just hood quivering along. I thought it might be a lack of support when it was designed but assumed GM would have solved that with extra bracing, I cannot see the structure on mine because of the hood pad. Is this just typical for the vintage of GM Caddy's? Also...the small Tri-angular rubber grommets (4) that are attached to the fencer where the hood ride are reducedto to age, I did try adding Addie too Al spacing there but no real result. Would like to replace those grommets if anyone has a source. Thanks-Dan
If possible, padding like under insulation, between the bracing might lessen the effect, don't remember this being an issue back when I worked for Cadillac.
Its not something I have noticed but I will have to look for it next drive. I wonder if yours is maybe too tight? I have missing bumpers and insulation so my whole hood will move and rattle.
Or was 74 unique? Did they have some new idea to shave 3 pounds of metal out of the hood structure?
It sure...my Eldo is black so I see everything going down the road staring at this long long hood...it's as if there is insufficient branching from the factory on the hood
Dan,
between the hood "skin" and the cross bracing below the factory inserted a mastic type filler to provide the strength of the bracing without the noise and vibration. If in fact you are getting a rippling effect of the hood skin you might assume that the mastic has dried out and separated from the structure, allowing the hood skion to vibrate freely. you should be able to check this wothout removing the hood (insulation) pad.
Greg Surfas
Thanks Greg, so can the mastic be replaced with destroying the hood? Or use another material?
If it has dried out and/or "disappeared" it can be replaced. If this is your case, check back and I'll try and find the remnants of the material I used.
Greg Surfas
Thanks Greg, will do...btw, have you had any experience with converting the divorced choke with a electric
Quote from: danjarrett1 on April 15, 2024, 10:42:08 AMDoes anyone have any experience with the oil-canning affect of this huge hood going down the road? I have adjust the rubber hood adjusters, they seem to be fine, however, the left and right sections of the hood seem to quiver going down the road. No rotational vibration from drive train, just hood quivering along. I thought it might be a lack of support when it was designed but assumed GM would have solved that with extra bracing, I cannot see the structure on mine because of the hood pad. Is this just typical for the vintage of GM Caddy's? Also...the small Tri-angular rubber grommets (4) that are attached to the fencer where the hood ride are reducedto to age, I did try adding Addie too Al spacing there but no real result. Would like to replace those grommets if anyone has a source. Thanks-Dan
It is not a problem with all, but just some. My theory is that many people like to pose beautiful babes on the hood of their cars. If on one of those photo sessions the position is wrong, or the weight estimate off, that initial indent is prone to come back.
That could have happened, who knows. The sheet metal that makes up this monster hood is not deformed in any way that I can tell, no indentations or warping, just long spans of sheet metal that tend to flex and quiver at highway speeds. One fellow did indicate that there was a foam like material between the gusset structure and the sheet metal of the hood. Over time, heat and wear, the foam-like material breaks down leaving a gap that can cause that to happen. I'm going to undo the hood insulation this weekend and take a peek at what is there. Thank you for your input.
I had this with my 61. The rubber pads on top of he fender under the hood were missing when I bought the car. I got new ones from rubber the right way and that fixed it.
Proper adjustment of all 4 hood resting pads will fix the problem. Start with new stem pads and go from there. Steele or Rubber the Right Way has them. Spray them with a little bit of silicone spray and they slip right on. Loosen the jamb nut and raise or lower as needed.
I have adjusted the hood stops at the front of the hood, I even enhanced the 4 triangle-like rubber bumpers in the sides, still not enough. The hood just needs to be stiffened up a bit, but I will continue up to tweak. Also, anyone has]ce a source for the side rubber cushions?
Check with two that I mentioned above. I think that they have on-line catalogs.
Is the hood pulling itself down at the back by the cowl/windshield?
No, the hood is not pulling back for force rear hood alignment problem. Did or some hood rubbers from caddy daddy. Will let you know if that resolves the issue. I do think that there is some material missing that was installed between the structure of the hood and the skin. Have offered a new hood insulation pad as well, will remove old one to gain access and go from there
Mine does do it. Never noticed before. Now I wonder if its going to bother me. I got home late so no time to investigate. I don't currently have hood insulation so it should be easy for me to see if that glue stuff is still sticking between the bits.
While wiping down the hood this morning I noticed that I could depress the hood on either side of the center stop at it would "oil can" where there is no bracing. One of the members suggested that a "mastic" type material was installed at the factory to deal with this. My car was repainted several years ago, they did a good job but they did not address this issue. I'm trying to identify what seaalent/glue/filler I can use to add solid structure. The simplest way to diagnose this issue is to gently press down on the hood panels at various location to see if the flex. Not sure how I'll fix it but driving down the road with the long shinny black hood flexing makes me crazy
One question. When the car was repainted, was the hood dipped in a solution to remove all the paint, inside and out?
If so, it could be that the solution also removed the factory sealer that was placed between the frame and hood panel whilst it was being assembled?
Bruce. >:D
I believe that is what happened. Hiw can I resolve this? Would expanding can foam for insulation work to fill in the gaps?
Quote from: danjarrett1 on April 25, 2024, 08:06:00 AMI believe that is what happened. Hiw can I resolve this? Would expanding can foam for insulation work to fill in the gaps?
The problem with the expanding foam is number one, it doesn't "grip" or bond to the steel like it should and will eventually come loose. Number two, is because it expands it can possibly push the hood away from the reinforcement structure distorting the skin to where you can see waves in it.
The correct product to use would be a panel bonding agent of some sort that doesn't expand, but bonds to the steel.
Your local paint and body supply store or a body shop can recommend the best one for this. I haven't done anything of this nature for decades, so my knowledge of what is available now is limited.
Rick
Thank you Rick...I did speak to a body shop today about that. I might let them just do it
I wouldn't use any expanding foam in case the expansion accidentally raised the hood skin higher in one spot, more than in others. This would really show up in the surface undulations.
I would have a look at mine, but seeing as I have a new insulation pad, I would rather not attempt to remove it.
Surely someone out there could measure theirs to see what it is? Plus, the trunk lid should also have the same material between the skins.
Many makers simply use a tarred felt layer between the panels, as when they get old, the parts not supported simply sag down and look awful.
Bruce. >:D
Dan,
There's probably about 20 different types of bonding agents or epoxies for the various body materials used in modern vehicles.
I remember that there was one that was recommended for the Pontiac Transport, Oldsmobile Silhouette,and the Chevrolet whatever it was, because they have a plastic skin over the metal framework of the body. The Pontiac Fiero was the same way.
On the hoods of the real cars from the 60's and 70's, the bonding agent is applied in small patches about half an inch to an inch in diameter depending upon where exactly it was used.
The one brand that comes to mind is 3M, they make all kinds of bonding agents. Steel to steel, aluminum, plastic, fiberglass, glass too I think.
The technology has changed so much since I was involved with a body shop back in the late 80's early 90's that if I need something like this now I'll have to ask the guys at the local paint supplier.
But like was mentioned earlier, the hood might have had someone sitting on it, which could have bent the reinforcement underneath the skin.
You would be money ahead to have a shop look at it for you before you do anything to it.
If you bond it yourself and you don't catch possible damage, you will cause yourself more headaches to fix that.
I'm not saying don't do it yourself, but just be aware of the possible problems you may encounter.
Good luck with your car.
Rick
Thank you Rick. The sub gusset structure now not appear to be compromised by anyone sitting on the hood. There's just a consistent gap that I believe, if filled with the right sealant, would stop the hood vibrations in cruise. 3M is the best product I know of for bonding material together for sure
Do you see places where the structure is touching the main panel? I will have to go look but I was thinking most places its touching.
Anyone have a parts manual what years were the hoods the same? I suppose that doesn't help since they could interchange even if they were trying some weight reduction design one year.
I will try to attach a pic for your review. Several places where there is a gap between structure and the hood skin