C2 A/C Evap Housing...Correct Finish for Screws

[James W.]

Can someone tell me what the correct finish is for the small self-tapping screws that hold the two sections of the a/c evaporator housing together on a 1965 Corvette? Also were the large nuts with the the built in shoulder supposed to be natural or were they blacked out after installation? These are the nuts that hold the blower motor housing and a/c evaporator box to the fire wall.

Thanks,

James West

[Chuck S.]

Re: C2 A/C Evap Housing...Correct Finish for Screw

You know, James, if none of these C2 gurus are going to step up and help you here, I can give you a best guess based on the C3 AC/heater box...use at your own discretion. Maybe I can shame them into telling me how wrong I am.

I would say that any small screws will be black phosphate, and for the firewall nuts, natural steel is a good bet. But, it's really irrelevant on any firewal fasteners...by the time it's blacked out, and that sealant gunk dribbled all over, I doubt you'll be able to tell what finish is on them.

[James W.]

Re: C2 A/C Evap Housing...Correct Finish for Screw

Chuck,

Thanks for your response. The car I'm working on is an original, unrestored '65, I'm doing a good cleaning in preparation for flight judging. I took all the screws off and soaked them in Ridrust solution and they do seem to be coated. It does look like black phoshate. The larger nuts were in fact a natural finish when they came out of the Ridrust soak.

Thanks again,

James West

[Chuck S.]

Re: C2 A/C Evap Housing...Correct Finish for Screw

James, you may already know this, but I want to make sure my comments above didn't mislead you.

Actually, in the C3s, and I'm pretty sure the C2s as well, I believe(?) the firewall was already blacked out when fasteners were used to assemble the AC evaporator/heater box to the firewall. That black sealing gunk would have later been dribbled over the top of the evaporator/heater box firewall interface, grommets, fuse block, and other penetrations.

Any fasteners visible on the bottom of the evaporator will need to have the correct finish...since the dribbling was powered by gravity, you won't see the sealing gunk running "uphill"