Topic: 1966 Convertible floor pan support bolt

[Twilight65]

Here's a picture of one of the 6 bolts I removed when dismantling the convertible floor pan support on my 66 Dearborn convertible. Is this the original? and if it is, why the hex shape on the one end?

Thanks,
Dave

[bryancobb]

I am awful with names and I apologize for not being able to address you buy name.  I just remember you have helped me several times and ways in the past 3 years.

I know a good bit about fasteners since I design structural steel sometimes.  Just bear with me. I hope I don't bore you.
This is an A325 Structural bolt.


 It is used in steel erection and these bolts MUST be tightened to a certain TENSION in the shank of the bolt, to achieve their strength rating.  This is NOT done with a torque wrench.  It is not accurate enough.  A special power tool is placed on the nut end that holds the TORX end stationary and turns the nut until the correct tension is obtained.  Then it slips to avoid over-tensioning.

The pressed-in captive nuts on the seat pans, where the brace plate bolts, were probably put in with a similar power tool.  I would guess that these bolts like the one in your picture, are "INSTALLATION BOLTS" were not suppose to be used to install the brace plate, since they would have been very costly.  On your car, they are probably the one that were installed at the factory, but not the correct ones.

[jwc66k]

All true about the A325 grade hareware except, the six bolts that hold the plate go to nutserts that have no access to the tip of the bolt. The special "tipped" bolt was probably installed after the car was built, in an auto shop that "lost" the originals.
Jim

[Twilight65]

Thanks for the information. The funny part is that in the Osborn Mustang Body Assembly manual the bolt in the drawing looks like the bolts I have. But as mentioned there is no access to the bolt end when installed.

Dave

[J_Speegle]

Thanks for the information. The funny part is that in the Osborn Mustang Body Assembly manual the bolt in the drawing looks like the bolts I have.

Well sort of - your bolt lacks the intergrated washer shown in the drawing - not that illustrations in these manuals are never wrong

[Bob Gaines]

Well sort of - your bolt lacks the intergrated washer shown in the drawing - not that illustrations in these manuals are never wrong

Just to elaborate on Jeff's post -a spinning washer with serrated edges.

[CharlesTurner]

The picture of the bolt above makes me think maybe it was a manufacturing miscue.

But, as mentioned, the original bolt has a thick captured washer with serrated edge on the bottom.  There are a few variances of head markings.  Some with an anchor insignia, some with a wavy flag.

[bryancobb]

Thanks for the information. The funny part is that in the Osborn Mustang Body Assembly manual the bolt in the drawing looks like the bolts I have. But as mentioned there is no access to the bolt end when installed.

Dave

Dave, the captive nuts were most likely installed on a jig, before the pan was welded in....

[Pete Bush]

Dave,

I crawled up under my May/June Metuchen Sprint and removed one of the 3/8" x 16 screws in question. Attached are pictures.
The captive serrated washer has a diameter of about 1.25". The length from against the washer is about 1". And there's an anchor design on the head.

Pete

[Twilight65]

Thanks Pete, I could see from the original teeth marks that the washer was 1.25 in diameter,  now I can get what I need.

Dave

[jwc66k]

The Ford p/n is 378044-S2, 3/8-16X1 1/8 HH bolt, disc lkw 1 1/4od. It is not in AMK catalog. Other head markings include: "flag", B & H.
Give me a PM.
Jim

[bryancobb]

Thanks Pete, I could see from the original teeth marks that the washer was 1.25 in diameter,  now I can get what I need.

Dave

Oh Dave,
If you can see the teeth marks, that changes the story I was trying to figure out about how the other type got in there.

[NEFaurora]

Dave, Just curious, Any type of marking on the top of the bolt that you removed? How were the other five bolts? Maybe someone removed the original bolt(s) to work on the tranny at one time.. ?

Tony K.