Installation instructions for door sills for Corvette C3

Allow between 1 and 2 hours for assembly.
All you need is a Phillips screwdriver, a 3mm drill bit, a screwdriver, a ruler, a cutter, and possibly a file.

Please note: if you have finished the car with body paint, with or without clearcoat, wait 15 days for everything to fully harden. The clearcoat dries quickly to the touch, but its maximum strength is reached after 2 weeks. If you install it too early, you will quickly have marks when getting in and out of the car, and you will have to start the finishing process again.

Upon unpacking, you will find a bag with the screws and quick connectors.


The sills have a direction; there's a left and right side; the small notch goes toward the front on the outside of the car.
The same goes for the light sections; the wire should exit toward the front, hence the notch.

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If you opted for models with primer only, you'll need to remove the lighted part to paint the sill.
It's simply clipped on; simply press the letters at one end to unclip it, then pull it back:


For reassembly, simply clip them back on from the back (pay attention to the correspondence between the right and left sides, the wire towards the notch)
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We start by removing the old threshold, there are just 4 Phillips screws to remove.


Next, you need to remove the plate on the side of the birdcage.
Remove the screw on the side and pull the plate toward the rear of the car.


On the passenger side, the footwell light is clipped onto the license plate; you have to remove it to remove the license plate.


Then, you may need to cut the carpet, the end must be 6cm from the edge of the threshold:



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The entire sill at the chassis level is very flat, except on the front towards the outside where there is a small bump.

The sill has a notch that usually fits, but our Corvettes are handcrafted, and there can be slight differences from one car to another (there are even some between the right and left sides 😉 ).
It may therefore be necessary to file the notch slightly to enlarge it. The sill is made of plastic; a wire file works very well.
It must be adjusted so that the sill sits flat. File from below at a 45° angle to avoid damaging the visible top of the sill:

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So let's move on to drilling the fasteners.
Start with the hole toward the front.
Position the door sill correctly, flat, with a 3 to 4 mm offset from the edge of the car.
Mark the hole position with a 3 mm drill bit.


Remove the sill, drill the frame with the 3mm drill bit, opening into the void underneath.
Insert the screw without the sill to create the thread. The screw has a diameter of 3.5mm, so you need to press firmly to create the thread in the frame.
Some screws may break at this point, which is why the kit includes a few extra screws.


Once the thread is formed, replace the threshold and secure the screw.
The other end should be flush with the riveted plate.


Some plates are not fixed quite straight, it may be necessary to adjust the edge at the end of the threshold:

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Now that the threshold is well held at the end, you can point the other 4 holes with the 3mm drill bit

Then remove the screw at the end and the threshold. You can drill the four holes and form the four threads.
A quick vacuum to remove the filings, and you can finally secure the threshold.
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The wire must pass under the carpet, so you must pass the carpet between the wire and the threshold:

Run the wire underneath and position the threshold.
You can now secure it permanently with the 5 screws. Start with the screwdriver, but don't screw it all the way in. Finish with the screwdriver to avoid damaging the threshold. The threshold must be firmly seated without overtightening; the screws should be flush with the threshold.


Now all you have to do is connect the wire to the footwell light bulb.
Open the connector by lifting the transparent part (there's a clip on the side).
Position the orange wire down so that it matches the positive side of the red sill wire.
Position the white wire up, matching the negative side of the black and red sill wires.
Close the connector securely with pliers so that the clip holds it in place. The wires will push into the small connections inside and make contact.

Test the lights before reinstalling the cover.
To reinstall the license plate, position it and push it toward the front of the car so that it snaps into place.

And replace the retaining screw.
The problem is often finding the hole for the screw: 2. Move the plate slightly apart and place a small drill bit or a point into the hole in the plate and aim for the hole in the frame.
Once the plate is in position, the point will give you the location to insert the screw.

It's now finished, repeat the operation on the other side and enjoy 😉