C2 A/C battery tray bolts

[Larry M.]

Re: C2 A/C battery tray bolts

Thanks Jim, I appreciate your checking your original. The short 1/2" version I have. Now if only I could find a half dozen of the apparently rare longer 3/4 or 7/8 bolts I'd be all set.

Call Richard Fortier............advertises in the Driveline.

Larry

[David B.]

Re: C2 A/C battery tray bolts

[QUOTE=Edward Dupere (60605);849144]Seems to be some dissent in the specs for the 9422606. David B calls it an 18 thread. In the archives there are a few posts calling it a 24 thread that is 7/8 long. The picture Stewart kindly provided shows a 24 thread. So, whats right? is it a 24 or an 18? I'm thinking that 24 is correct as the frame thickness is not reinforced in this area (for left hand battery tray) and the 24 might provide an extra thread in the metal over the 18. Also, the similar marked ((D)) spare tire tub bolts that also thread directly into the frame, are 24s. Too bad they are only 1/2" long otherwise I'd use them for this since they would look right and are available.[/QUOTE


The dimensions quoted for #9422606 is CORRECT per GM Engineering Standards. If you are convinced your fastener is correct, check for a different part number.

[Edward D.]

Re: C2 A/C battery tray bolts

David,
Could you possibly post a copy or pic of the page of "GM Engineering Standards" you refer to? I'd sure like to see the tech doc where the 9422606 is specified as an 18 thread bolt. Every original bolt I have seen to date has been a 24 thread.


[QUOTE=David Bartush (3288);849165]

Seems to be some dissent in the specs for the 9422606. David B calls it an 18 thread. In the archives there are a few posts calling it a 24 thread that is 7/8 long. The picture Stewart kindly provided shows a 24 thread. So, whats right? is it a 24 or an 18? I'm thinking that 24 is correct as the frame thickness is not reinforced in this area (for left hand battery tray) and the 24 might provide an extra thread in the metal over the 18. Also, the similar marked ((D)) spare tire tub bolts that also thread directly into the frame, are 24s. Too bad they are only 1/2" long otherwise I'd use them for this since they would look right and are available.[/QUOTE


The dimensions quoted for #9422606 is CORRECT per GM Engineering Standards. If you are convinced your fastener is correct, check for a different part number.

[Edward J.]

Re: C2 A/C battery tray bolts

Ed, Every bolt that the holds anything to the frame, fuel and brake lines, battery tray etc. is a 24 count thread, not to say a 18 thread count will not work.

[David B.]

Re: C2 A/C battery tray bolts

Ed, Every bolt that the holds anything to the frame, fuel and brake lines, battery tray etc. is a 24 count thread, not to say a 18 thread count will not work.

Do not disagree re: use of 24 count thread screws. If you can provide the part number for each individual usage it sure makes things a lot easier to verify it's dimensions etc.. Per request will attempt to post 9422606 specs.. Repeat: it is not a 24 thread screw.

[Jim D.]

Re: C2 A/C battery tray bolts

Okay, here's what we know:
1. 1965 A.I.M states the bolt used is 9422606
2. GM Engineering Standards, according to David, state that 9422606 is a 5/16 X 18
3. The bolt that was ACTUALLY used in production is a 5/16 X 24

Conclusion, either 1 or 2 is incorrect.

[Gene M.]

Re: C2 A/C battery tray bolts

As installed here on earth the screw will not be visable to discern which thread it is be it fine or course thread. There is so little thread interface engagement in all honestly it will not make any difference, the world will still rotate.

[Edward D.]

Re: C2 A/C battery tray bolts

Well, since I was unable to locate 3/4 or 7/8 long bolts with correct head markings what I finally ended up doing is what Ed Johnson initially suggested. I used the 5/16-24 X 1/2 "double circle D" indented hex head bolts w/black phosphate finish, same as used for the spare tire tub. Turned out that they were just long enough to get thru the thick washers, tray flange, and into the frame. Had to do a little work to a couple holes wallowed out by incorrect bolts, but it all worked out well in the end. In sum its now tight and correct appearing. Thanks to all for your help.

[Mike B.]

Re: C2 A/C battery tray bolts

Hi Guys,

When I removed my battery tray, thick washers, and recessed hex head bolts from my '66 AC L36 just after I bought it in 1988 I could tell that none of it had been removed before. The screws measure 5/16 - 18 x 3/4" black phosphate, grade 2 with no head marks. I've since bought a real set of double circle "D" fine thread screws to use since that's what's commonly reported on 396 and AC cars. I thought maybe my car was a fluke?

Well, I've since met a good Corvette buddy David Harris who also owns an L36 AC '67. He's been carefully documenting his '67's disassembly down to each nut and screw. He just removed his tray, thick washers, and recessed hex head bolts. The screws measure 5/16 - 18 x 3/4" black phosphate, grade 2 with "E" head marks. David wanted me to post these 3 shots of his AC battery tray bolts for you all to see. He's having too much fun taking his Vette apart!

Thank you David Bartush for posting your GM Specs for screw #9422606. This screw number is listed in the '65, '66, '67 AIM C60 section Sheet E2. We have confirmed your specifications by referencing GM Engineering Standards, Section D. Probably the source you used. Most probably the fine thread screws were used en masse. But here's a couple of guys who had the coarse thread screws installed on their Vettes. Mike

GM Spec. for #9422606 is Hexagon Head Tapping Screw 5/16 - 18 x 3/4 phosphate coated type C

[Edward D.]

Re: C2 A/C battery tray bolts

All, Thanks for all the checking! I posted the original inquiry for the 1965 I'm assembling. Seems like there is a lot of variation and opinion out there. I also checked a what I believe to be an original car, a 1967 L71 with a/c, a benchmark never restored original car. With owners permission, I pulled one battery tray bolt and it is a 5/16- 24 thread cutting bolt. I could not make out any head mark and would have had to remove blackout/undercoating to see the head mark which the owner did not want me to do. Bottom line, a 24 thread bolt for sure.

[Edward D.]

Re: C2 A/C battery tray bolts

Mike,
i have asked this question before, but here it is again. Where can I find a copy of these "GM Engineering Standards" section D or any other section for that matter? Care to post a screen shot of a page? I have a number of GM Standard Parts catalogs and other GM documents, and have checked GM Wiki which has a lot of GM publications but cannot find what you and David quote. Please backup what you say with documents. I should be most interested in seeing a GM document that says a p/n 9422606 is an 18 thread bolt.

Hi Guys,

When I removed my battery tray, thick washers, and recessed hex head bolts from my '66 AC L36 just after I bought it in 1988 I could tell that none of it had been removed before. The screws measure 5/16 - 18 x 3/4" black phosphate, grade 2 with no head marks. I've since bought a real set of double circle "D" fine thread screws to use since that's what's commonly reported on 396 and AC cars. I thought maybe my car was a fluke?

Well, I've since met a good Corvette buddy David Harris who also owns an L36 AC '67. He's been carefully documenting his '67's disassembly down to each nut and screw. He just removed his tray, thick washers, and recessed hex head bolts. The screws measure 5/16 - 18 x 3/4" black phosphate, grade 2 with "E" head marks. David wanted me to post these 3 shots of his AC battery tray bolts for you all to see. He's having too much fun taking his Vette apart!

Thank you David Bartush for posting your GM Specs for screw #9422606. This screw number is listed in the '65, '66, '67 AIM C60 section Sheet E2. We have confirmed your specifications by referencing GM Engineering Standards, Section D. Probably the source you used. Most probably the fine thread screws were used en masse. But here's a couple of guys who had the coarse thread screws installed on their Vettes. Mike

[David L.]

Re: C2 A/C battery tray bolts

The photos of the 5/16"-18 bolts with the letter "E" reminded me of the fuel line and brake line clip "E" bolts that I removed from my 1966 back in 1980 when I first started my frame up restoration. Attached is a photo of 4 GM bolts, # 9420825 , 5/16"-18 X 9/16", a bit too short for the AC battery box bolts ( GM # 9422606). Back in 1980 I sprayed them with some silver paint to prevent further rusting. They have been stored away for the last 39 years in a box marked 5/16" Corvette bolts. The effective lengths of my original 9420825 "E" bolts measure 0.56" to 0.58" so they are 9/16" nominal whereas Paragon Corvette sells reproduction 9420825 "E" bolts as 5/16"-18 X 1/2" .

BTW, As I remember the fuel line bolts on my 1963 Split Window Coupe were 5/16"-24, GM # 171109.

Dave

[Rich P.]

Re: C2 A/C battery tray bolts

63 through 65 battery tray bolts with a c and 396 were all 5/16 24 fine thread with a tapered tip to cut the threads. 66 through 67 AC battery tray bolts or 5/16 18 with the same type of taper tip. Most common head marking 4 65 was D in circles followed by IM and then blank.