Rear astro vent grills on c3's...

[Brandon T.]

Re: Rear astro vent grills on c3's...

Brandon, home depot had some black oxide pan head screws that I brought for my 72, they worked great and they were the right size heads. (3.00 for 8 of them) as for the j-nut? maybe its just slipped inside the recesses area there if you lucky, take a flash light and look in.

already did that! I just KNEW it would be there, but nope.

ah well.

[Edward J.]

Re: Rear astro vent grills on c3's...

Maybe lowes, do ya have one of those in your area. they also have a good supply of hardware.

[Brandon T.]

Re: Rear astro vent grills on c3's...

I'll look around..

anyway to get accress to where that drain hole is at the bottom of the vent area? I've bet anything that clip has fallen into that drain out and back up under there sometime or another when that grill has been taken off.

if goes back up udner there not sure how to get access to that area tho.

[Edward J.]

Re: Rear astro vent grills on c3's...

Take a magnet, when you remove the grills maybe you can reach in with magnet.or if you don't find it just throw alittle piece of strip chalk to hold the screw in place, its not like 5 other ones won't hold.

[Brandon T.]

Re: Rear astro vent grills on c3's...

Take a magnet, when you remove the grills maybe you can reach in with magnet.or if you don't find it just throw alittle piece of strip chalk to hold the screw in place, its not like 5 other ones won't hold.

I did, I put a magnet down in the drain hole and it couldn't reach anything close enough, it still might be down in there.

That hole goes back up under the rear of the car anything that went into that drain could have fallen back out of reach.

[Edward J.]

Re: Rear astro vent grills on c3's...

Brandon, I think the rubber drain hose can be accessed from inside the car, but after all these years those hoses maybe better off left alone.

[Chuck S.]

Re: Rear astro vent grills on c3's...

Brandon, home depot had some black oxide pan head screws that I brought for my 72, they worked great and they were the right size heads. (3.00 for 8 of them) as for the j-nut? maybe its just slipped inside the recesses area there if you lucky, take a flash light and look in.

Pan head??!! PAN HEAD??!!

Edward, pan head screws are about as different from the originals as possible. About three people in this thread have said that the screws are supposed to be flat head countersinking metal screws. You would be better off using #6 or #8 wood screws, 1/2" long, painted black.

I think there is confusion on the head descriptions. (The following exerpted from http://en.wikipedia.org/wiki/Screw which has other valuable information on fasteners)

Screw head shapes


(a) pan, (b) button, (c) round, (d) truss, (e) flat (countersunk), (f) oval



Pan head - A low disc with chamfered outer edge

Button or dome head - Cylindrical with a rounded top

Round head - Dome-shaped, commonly used for machine screws

Truss head - Lower-profile dome designed to prevent tampering

Flat head or countersunk - Conical, with flat outer face and tapering inner face allowing it to sink into the material

Oval or raised head - Countersunk with a rounded top

Bugle head - Similar to countersunk, but there is a smooth progression from the shank to the angle of the head, similar to the bell of a bugle

Cheese head - Disc with cylindrical outer edge, height approximately half the head diameter

Fillister head - Cylindrical, but with a slightly convex top surface. Height to diameter ratio is larger than cheese head.

Flanged - A flanged head can be any of the above head styles with the addition of an integrated flange at the base of the head. This eliminates the need for a flat washer.

Mirror screw head - Countersunk head with a tapped hole to receive a separate screw-in chrome-plated cover, used for attaching mirrors

Headless (set or grub screw) - Has either a socket or slot in one end for driving

[Jim T.]

Re: Rear astro vent grills on c3's...

What most people don't realize is that this is a very unique screw and this is it's only Corvette/GM application. It has a counter sunk head with a flat on the bottom that fits perfectly into the vent grill. and the flat head of the screw sits flush with the grill. the screws in the repro kit are more than twice as long as the originals and don't have the flat on the taper of the counter sunk portion. Look at the picture of the originals I posted compared to the originals.

Another thing is the U-nut is a pretty unique item as well but we can save that for another post.

Rich.

Rich the screws for the front grille are unique as well. I am glad I did the repaints my 68 and 70 and retained the original front and rear grille screws.

[Harmon C.]

Re: Rear astro vent grills on c3's...

If you have original drain hoses you better replace them or if you get caught in the rain you may fill the car with water.

[Edward J.]

Re: Rear astro vent grills on c3's...

Chuck , Thanks for that dia. I stand corrected, I knew the correct screw head, but did not use the correct term. I knew it was a flat head, should have just said that, because I recently went through this with my 72.

[Gene M.]

Re: Rear astro vent grills on c3's...

Guys:
The correct terminology for the screws this post has been referring to is oval head jackson screw. The simple difference from the hardware store variety is the head is a #6 with a #8 sheet metal thread body.

Jackson head screws are also offered with a machine thread.