Wednesday, February 16, 2022

Making a Hood Lockpin Alignment Tool


Locking yourself out of your engine bay is one of the most frustrating experiences a C3 Corvette owner can have.

The 1969 through 1976 Corvette hood-locking system is ingenious, but the fact that it can be adjusted opens the door to the chance for the misalignment of components that, otherwise, should not be adjustable.

But since C3 Corvette panel fit is not great, adjustability is required. Unfortunately, adjustability opens the chance for misalignment that will keep you from being able to fully open the hood.

The culprits, in this case, are the hood lockpins (driver's side lock pin shown above). A tiny fraction of an inch is all it takes for the pin flange to get caught by the latch edge as illustrated below. From there it's all downhill as your Corvette's hood gets stuck in the closed position.

However, this article is not about how to open a stuck hood. This article is about preventing that from happening.

If you are unable to open a stuck hood, there are several YouTube videos on the subject. 

Above: Image shows problem area.
I recently had to align the lockpins since I had the hood off to install a new aluminum radiator, and as careful as I was, I still ended up with a stuck hood.

The drawing helps illustrate how these components interact and cause the hood to get stuck in the locked position.

You can pull the Hood Release lever all you want, but that won't solve the issue, and you will have to manhandle the hood and hope that will work without causing damage.

I was able to pop my Vette's hood open the next day after figuring out where the latch was caught.

This headache could've been completely avoided had I used the simple alignment tool I describe here.

I did not come up with the idea, or at least not completely.

Geoff, one of my YouTube subscribers watched the video where I share I had locked myself out of the engine bay and he suggested a simple yet effective solution: Use a lawnmower spark plug socket for pin alignment.

For a system that offers adjustability, there's little if any room for error.

I experimented with a couple of spark plug sockets but their outside diameter was too thin, and you need an alignment tool that will be perfectly centered in the latch opening (with the lock tab out of the way).

Above: Right-Hand Side Hood Latch.

Above: Left-Hand Side Hood Latch.

After trying different sockets, a 13/16-inch impact socket fits over the lockpin perfectly, even though it was still too thin to be centered in the latch. And that's when I had an idea: Make a sleeve!

Since one of my neighbors recently gave me a bunch of PVC pipes he no longer needed, I had a variety of sizes available, and by sheer luck, one fit the socket and the latch opening like a glove. So I cut a small piece about 1-1/4-inches tall as a sleeve.



And believe it or not, these are all the items you need to make your hood lockpin alignment tool. And since you have to align one pin at a time, you only need one.

These are the dimensions:

  • PVC Pipe: 1-5/16" (33 mm) outside diameter.
    1-3/16" (29 mm) inside diameter.
  • Cut the pipe to 1 1/4" (32 mm) tall.

You can make the sleeve out of a metal pipe, if necessary, or print one if you have a 3D printer.

There are machined aluminum hood lockpin alignment tools available, which I am sure work great, but at around $20 to $40 plus shipping depending on the vendor, why spend that kind of money if you can make one just as good for close to nothing?

Anyway, that's what I did and this is the finished product.


The sleeve fits over the socket and you want to align the latch with the lockpin by lining up the hex side of the socket precisely over the pin's head.



The PVC sleeve also fits snuggly inside the latch opening. You have to manually retract the locking tab and then push the sleeve and socket in as shown in the photo below. 

The procedure applies to both latches.



You will need to loosen the bracket that secures the lockpin in place. There are a couple per side.

Loosen the nuts enough so you can position the lockpin assembly in place as you lower the hood carefully and the alignment tool is perfectly seated over the lockpin.


Adjust manually as needed ensuring the adjusting tool remains perfectly centered over the lock pin. Fully open the hood and carefully tighten the nuts so the bracket stays in the exact position. 

Then lower the hood again with the alignment tool in place to ensure the latch and lockpin are perfectly aligned  (photo below).

When you're satisfied with the alignment, tighten the nuts one final time and repeat the procedure for the other side.


And that's all there is to it!

If you use the right tool, whether it is a DIY tool like this example or a machined aluminum tool, you will be able to align the hood locking pins properly and precisely, and you will avoid the stuck C3 Corvette hood syndrome.

I also posted a video of how to make an alignment tool to my YouTube channel. Click the video below to watch it.

From what I've read, this DIY tool will work on C3 Corvettes from late 1969 through 1976 but I have not confirmed this. However, it works perfectly on my 1976 Stingray.

Good luck with your project!


Thank you for following my 76vette Blog!




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