1956 1957 Hood Pop Ups and Hinge Adustments

[Richard M.]

Having trouble getting hood to stay down in front when latched. Will tightening the pop ups help or worsen?

[Scott S.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

Richard, If you screw them down I will asssit, but be careful when you open the hood, lift it from the center at the rear.
Scott

[Tom A.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

I find that normally aftermarket springs are too strong. Reuse originals and it should sit at correct height.
Tom

[Richard M.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

Yes, agreed, we have all original hinges and popups and male/female latches. I'll post some photos when I get back on the computer.

[Richard M.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

I did this a few years ago on a '56 and had to re-familiarize myself with this design today. It brought back bad memories..

The hinges articulate. There is a "overcenter" sweet spot when the hinge is lowered which then brings the hood edge straight down on to the popups. When the hood is latched at the rear, this must also, by design, put pressure downward on the front of the hood against the popups.

We spent many hours trying to get the hood adjusted in all directions with reasonable gaps and finally attained that. However, the driver side of the hood front edge remains raised, and no matter whatever we tried to adjust.....failed.

After looking at the popup construction, it cannot be lowered. The shoulder bolt has a defined length and cannot be adjusted. It holds the spring and cup in a set position. The popup bracket mounts to a fixed non-adjustable pair of holes in the core support, so it cannot move vertically up or down.

We removed the male latch assemblies, lower the hood, and still same fault. We gave up for today and will attempt another time.

In the past I've heard of folks cutting coils of the springs to aid in this issue, but I don't know if I want to risk cutting original springs. I also heard that shims between the bottom of the spring and the bracket, to compress the coils, shortening the unsprung length of the coil while keeping the top height the same, is a way to overcome the problem. We may try that, a job for "tomorrow-man".

The "Vent".......This is by far one of the worst ever mechanical designs I have ever encountered. Very frustrating, even for me, the patient one.

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[Richard M.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

Answer, from Roy Braatz..........HERE back in 2009. Also input from John Hinckley confirming same on his own 1957 restoration. Thank You Roy and John.

Basically Roy says to add shim(s) to the rearward/top bolt of the hood hinge(where it mounts to the hood itself) to gain more "overcenter" of the hinge coming down to compress the popup. I believe this is our solution and will attempt this next.

Also similar info quoted from the CF from Roy HERE.

I see hood hinges and pop-ups where the holes are extra elongated trying to fit the hood on 53 to 57 Corvettes all the time. That's because few know how to adjust or know what to do to make the hood fit and open CORRECTLY .
1. The pop-ups are there to only lift the hood front line UP when you release the rear latch's pulling the hood cable so as to NOT chip the paint on the body.
2. The hood HINGES are moveable (only a little to AID in pulling the hood FRONT area DOWN ) in the last few inch's of closing.
3. The two fiberglass stoppers holes are elongated so that you can move them UP or Down to meet the thickness of the HOOD when closed.
4.Now if the front hood line sits too high , adding shims ONLY at the hinge top bolt on both sides will canter the angle pulling the hood line down.
5." Repro" pop-up AND rear male hood pins's springs {suck} because the wire is too thick making the front pop-ups to strong and cause the rear hood male pins to open when driving. ( if you cut a coil off to where the spring just put a little tension on the cup , your problem will be solved .
6. Number 5 is why you see the hood male latch and female latch holes elongated also.
7. A good looking working hood is when the hood front line pops-up at the same time the rear latch's pop-up, that's HOW it works PEROID .

PS the reason you see some one using both hands to lift the hood if adjusted correct is because the hood bracing BOND has come loose from the hood skin.

PS again the front hood hinges are designed to go OVER CENTER to pull the hood down compressing the pop-ups. That's WHY it has TWO arms!!!!!!

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[Chris S.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

I take original latch springs and transfer them to the repro latches. Makes a huge difference in the rear latch operation. The repro spring is too thick and stiff.
I attach the rear male latches to the hood loosely - the latches should hit the female latches dead center - you can move the hood latches to hit correctly - also you can move the female latches so they male latches hit dead center.
Check your gaps - front to rear and side to side.
They are a pain - but patience......

[Dan D.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

On my 57 the pop-ups were missing, so I bought repos. Sure enough, the front of the hood was high. So I just took them back off. The hood seems to fit good and the rear still pops up when opened. Not knowing these details at the time, well, I could not figure it out so I just figured the heck with it. I have always lifted the hood from the center to prevent the fiberglass from being torn loose at the hinges.

So now I will try cutting a coil off the repros and see if that fixes it. And yes, the mounting holes in the hinges are slotted.

These old C1s sure have a lot of secrets that are slowly coming to light. I had the same problem with the door release rod springs that have just been discussed here on another thread. I figured out how to solve that on my own - just like Rich and others have done. Interesting though, when I took my right door apart, the release rod spring and washer was installed per the AIM and had dropped down on the rod. I don't believe that door had ever been apart. There was no evidence of it.

-Dan-

[Richard M.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

Thanks Gents, We haven't been back to the hood but we will do that soon. I'll update after we fix it.......We WILL fix it.

Rich

[Richard M.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

We DID fix it.

After closing the front gap a tad more by loosening the hinges at the core support and tilting both forward a bit(there's a small amount of play in the holes), we then added one shim(apx 1/16" thick) on the DS upper/rearward hinge(to hood).

That slight thickness of the shim at that position causes the articulating hinge to go"overcenter". Before it must not have made it to that point and needed the shim to get it there. This pulls the hood front edge down onto the popups with more "pull".....just like it's designed to do. Now that I understand how this works, I feel compelled to apologize to the designers. In fact, I looked in the AIM again yesterday after we fixed it. It does in fact show "Shim (As Required), at that hinge location.

Rich
PS One caveat. The DS male latch is having a tough time catching the female latch and staying closed. We have a plan to solve that by readjusting the male mount plate holes for more adjustment, or shimming the female latch to firewall for more grab angle, or replacing the male latch with NOS(we have several to choose from, with "ridges"). If we have to, we may have to divert to the "cut-the-notch-in-the-side-of the-pin" method, albeit not our preferred solution.
PPS You have to really do this yourself to experience how much fun it is. We probably have a man-day or more into this hood "adjustment".

[Chris S.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

fits great !!!!!

[Barry H.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

Rich, You are right the "shim" under the rearmost hood bolt gives you just a little overcenter action. I saw many of the original 56/57's that used this trick, many time more than one shim was used. Sometimes the shims were lost or discarded whenever the hood was later removed. I believe the hood was installed & fitted in the body shop & the shims were installed before prime or painting. Later in production the rear hood pin with "ridges" was used due to complaints about hoods popping up on their own. Try to look at "Bowtie" or "Survivor " 56/57's to see that the shims were installed before painting & engine compartment blackout. I worked on some original low mileage 56/57's back in the late 60's & 70's. Barry Holmes

[Richard M.]

Re: 1956 1957 Hood Pop Ups and Hinge Adustments

Rich, You are right the "shim" under the rearmost hood bolt gives you just a little overcenter action. I saw many of the original 56/57's that used this trick, many time more than one shim was used. Sometimes the shims were lost or discarded whenever the hood was later removed. I believe the hood was installed & fitted in the body shop & the shims were installed before prime or painting. Later in production the rear hood pin with "ridges" was used due to complaints about hoods popping up on their own. Try to look at "Bowtie" or "Survivor " 56/57's to see that the shims were installed before painting & engine compartment blackout. I worked on some original low mileage 56/57's back in the late 60's & 70's. Barry Holmes

Thanks Barry. This helps confirm what we went through.

After going through this adventure, I was thinking also that since the hood was mounted before paint that if shims were already there from previous fitting, at blackout they would then have been painted at their exposed edges. I can imagine now over the years when the hood got removed and reinstalled, many times the shim would be forgotten and wouldn't close at the front.

The hood was removed from this car many years ago, and probably had some shims installed but got lost and forgotten.

Rich