1966 AC Ducting Mount Screws

[Mike B.]

Hey all,

Does anyone know the correct size, plating and headmark of 1966 AC plastic ducting mount screws? These are the ones that screw from under the left and right hand duct assemblies. Also, if anyone knows the same stats on the "D" clamp screw that joins the right AC duct to the inner pan outlet, it would be most appreciated.

Thanks, Mike

[Wayne M.]

Re: 1966 AC Ducting Mount Screws

Hey all,

Does anyone know the correct size, plating and headmark of 1966 AC plastic ducting mount screws? These are the ones that screw from under the left and right hand duct assemblies. Also, if anyone knows the same stats on the "D" clamp screw that joins the right AC duct to the inner pan outlet, it would be most appreciated. ...

Mike -- closest I can offer is off my early '65 (believe ducting and brackets are the same as '66). AIM UPC C60, Shts. A4 & A5 show seven sets of screw 9417226 and plain washer 3769610; six of these go on the driver side (outer bracket & inner bracket) and one goes to the passenger side, on the birdcage just above the kickpad vent/carpet.

In the pic, the two on the right are supposed to be the same. The duct "D" bracket screw is shown installed; the one in the middle is what was holding the passenger duct to the birdcage; the right screw and washer was one that held the plastic duct to the inboard driver bracket. All other screws are obviously wrong; ie. my driver outboard bracket has slotted hex head screws. So maybe one or more of these is correct. They're all 5/16" recessed hex, you can see two have integral flanges. The one with the "L" headmark has some reddish-orange coloring, so obviously this is wrong. I'd bet the washers are wrong as well .

[Chris W.]

Re: 1966 AC Ducting Mount Screws

Hey all,

Does anyone know the correct size, plating and headmark of 1966 AC plastic ducting mount screws? These are the ones that screw from under the left and right hand duct assemblies. Also, if anyone knows the same stats on the "D" clamp screw that joins the right AC duct to the inner pan outlet, it would be most appreciated.

Thanks, Mike

I believe the screws that attact the outer ends of the ducts to the duct mounting brackets are Black phosphate 5/16 "High Hat" sheet metal screws. The screw has a tall hex head which makes it easier to align the screw when it is being installed. There is no washer involved, just this special screw.

I am not sure but this same screw may also have been used for the "D" clamp on the R/H duct and the two other mounting screws on the L/H Duct.

I am going from memory which is not always the best and I do not have my '65 A/C Coupe here to look at (which I believe is the same).

I do know screws with a hex head and a slot are not correct.

Chris

[Rich P.]

Re: 1966 AC Ducting Mount Screws

I have seen at least 3different configurations and 10 different headmarkings.

First the High Hat screws they have a 1/4" recessed hex head with a built in flange. They also were used for 64-65 Fuel Injection S-Tube to radiator supports as well as the heater-A/C bowden cable to heater boxes. They have several different headmarkings, Anchor, double Anchor, A in 2 circles and blank.

Second 5/16" recessed hex head with a built in flange. This has the most headmarkings of all the screws. D, Anchor, double Anchor, GL, A, 3 dots, M, and several others.

Third 5/16" recessed hex head no flange with L for it's headmarking. (Wayne this is the one in your picture that has a red hue to it. That is 100% original they came black/grey phosphate and sometimes turned reddish brown when weathering)

Mike 99% of the time they were all black phosphate. And anyone of the above mentioned bolts could have been used in these positions.

If you want I can try to dig some up to take pictures of as I know I have tons of each.

Rich

[Chris W.]

Re: 1966 AC Ducting Mount Screws

I believe the screws that attact the outer ends of the ducts to the duct mounting brackets are Black phosphate 5/16 "High Hat" sheet metal screws. The screw has a tall hex head which makes it easier to align the screw when it is being installed. There is no washer involved, just this special screw.

I am not sure but this same screw may also have been used for the "D" clamp on the R/H duct and the two other mounting screws on the L/H Duct.

I am going from memory which is not always the best and I do not have my '65 A/C Coupe here to look at (which I believe is the same).

I do know screws with a hex head and a slot are not correct.

Chris

CORRECTION,

I should have said that the "High Hat" screws were 1/4 in Hex, and NOT 5/16 in. Hex head. There were 5/16 regular hex head screws used in other areas of the underdash. I am not sure the "High Hat" screws were used on all Mid Year A/C Ducts, but I know I have seen them on '65s and I think also some '66s.

Chris

[Mike B.]

Re: 1966 AC Ducting Mount Screws

Mike -- closest I can offer is off my early '65 (believe ducting and brackets are the same as '66). AIM UPC C60, Shts. A4 & A5 show seven sets of screw 9417226 and plain washer 3769610; six of these go on the driver side (outer bracket & inner bracket) and one goes to the passenger side, on the birdcage just above the kickpad vent/carpet.

In the pic, the two on the right are supposed to be the same. The duct "D" bracket screw is shown installed; the one in the middle is what was holding the passenger duct to the birdcage; the right screw and washer was one that held the plastic duct to the inboard driver bracket. All other screws are obviously wrong; ie. my driver outboard bracket has slotted hex head screws. So maybe one or more of these is correct. They're all 5/16" recessed hex, you can see two have integral flanges. The one with the "L" headmark has some reddish-orange coloring, so obviously this is wrong. I'd bet the washers are wrong as well .

Hey Wayne - Thanks for the quick response and shot of the screws! The ones on the left look like the ones I suspect are correct. Any side shots? How long are they? Dimensions? All my originals are gone. Thanks, Mike

[Mike B.]

Re: 1966 AC Ducting Mount Screws

I believe the screws that attact the outer ends of the ducts to the duct mounting brackets are Black phosphate 5/16 "High Hat" sheet metal screws. The screw has a tall hex head which makes it easier to align the screw when it is being installed. There is no washer involved, just this special screw.

I am not sure but this same screw may also have been used for the "D" clamp on the R/H duct and the two other mounting screws on the L/H Duct.

I am going from memory which is not always the best and I do not have my '65 A/C Coupe here to look at (which I believe is the same).

I do know screws with a hex head and a slot are not correct.

Chris

Hey Chris - Thanks for the response. Yep, they were definately unslotted hex head with washer lip/black phosphate. Any memory of overall dimension/headmark? Thanks, Mike

[Mike B.]

Re: 1966 AC Ducting Mount Screws

I have seen at least 3different configurations and 10 different headmarkings.

First the High Hat screws they have a 1/4" recessed hex head with a built in flange. They also were used for 64-65 Fuel Injection S-Tube to radiator supports as well as the heater-A/C bowden cable to heater boxes. They have several different headmarkings, Anchor, double Anchor, A in 2 circles and blank.

Second 5/16" recessed hex head with a built in flange. This has the most headmarkings of all the screws. D, Anchor, double Anchor, GL, A, 3 dots, M, and several others.

Third 5/16" recessed hex head no flange with L for it's headmarking. (Wayne this is the one in your picture that has a red hue to it. That is 100% original they came black/grey phosphate and sometimes turned reddish brown when weathering)

Mike 99% of the time they were all black phosphate. And anyone of the above mentioned bolts could have been used in these positions.

If you want I can try to dig some up to take pictures of as I know I have tons of each.

Rich

Rich - You are the man! Figured you would know. And thanks to all the other responses from everyone. Yes Rich, I'd really like some pics/application/dimensions and headmarks. Did the D-duct clamp use the same size as the end ducts? The repros are way off. Thanks, Mike

[Wayne M.]

Re: 1966 AC Ducting Mount Screws

Rich - ..... Did the D-duct clamp use the same size as the end ducts? The repros are way off.....

Mike -- I doubt that the D-clamp screw would be the same size; mine is longer than the other two in the pic (and seven in total, per '65 AIM). And the D clamp has a different part # than the seven.

Rich --- 'WoW' is all I can say about your explanation of the L headmark with the orangey-red.

Would be nice if a few others reported headmarks -- after all, these are not difficult to see.

[Rich P.]

Re: 1966 AC Ducting Mount Screws

Yes Rich, I'd really like some pics/application/dimensions and headmarks. Thanks, Mike

First picture is of different Anchor headmarkings single and double.

Second picture is of 4 D bolts with different headmarkings

Third oicture is a mix of other know markings used at this time period. Left to ight isGL, P, E w/dot, IM, Double Dash and NL.

Rich

[Rich P.]

Re: 1966 AC Ducting Mount Screws

Did the D-duct clamp use the same size as the end ducts? The repros are way off. Thanks, Mike

Mike,

I have a set all wrapped up ready to go on a 65 A/C car. I will try to dig them out later. But the AIM calls for the D clamp screw as pt # 3776999 while the duct mounting bolts are pt # 9417226. So it is a different bolt. It will be a week or so before I can dig out the bolts for the 65 (it was an original untouched car).

Rich

[Rich P.]

Re: 1966 AC Ducting Mount Screws

Rich --- 'WoW' is all I can say about your explanation of the L headmark with the orangey-red.

Wayne,

here are a few pics of 2 different L bolts like in your picture.

First is a shot of 2 bolts with a integral washer. It's hard to tell from the picture but one of them is getting the reddish brown color you mentioned.

Secod is of one of the bolts with the integral washer and one with out. The one with out is a little longer and has a larger more agressive thread (This is an original 63 FI S-Tube to radiator support bolt)

The third picture is the head of the 2 from the second picture.

Rich