Topic: 67 taillight retaining nut differences

[67gta289]

Working with Bob M (19667Bob) on a side job and while doing research we ran across another potential 67 change.  I know, right?

Looking at the nuts that retain the taillight housings, I had made the claim that they were all pretty run of the mill hex nuts with captive star washers.

In looking through pictures of unrestored cars, like the one shown in picture T-4 here: http://www.concoursmustang.com/forum/index.php?topic=18570.0 I was confirming what I thought.

I probably have pictures of 100 cars like this.   Bob was asking me about the 377523 listed in the assembly manual and shown in the attached MPC.

Then I ran across 7R02C116xxx (picture attached) which is a good example of the hardware used on the rare lower back panel grille option.  But if you look closely at the driver's side taillight housing you will see the 377523 nuts.

I guess my next step is to comb through the files and see if this is an early/late thing.

I looked at 5 different 68's and they are all the hex/captive washer ones I would expect.

[67gta289]

Upon further review...it appears that the 377523 part number is in question.  If you compare the MPC installation diagrams, both the standard and lower back panel grill option reference 377523.

We know that the standard nut is a hex nut with captive star/tooth washer.

The MPC, as well as the picture of 7R02C116xxx show that the nut used on the lower back panel grill as a completely different type of nut, even though the part number is the same.

Other than the -S and -S100 suffix, which should only represent the finish.

[67gta289]

Referencing the attached fastener document pictures, as well as the MPC and assembly manual, the 377523 is the correct number for the nut used on the lower back panel grille for attaching the taillight housing.

The correct number for standard installation would be 34653-S36 (zinc dichromate).  The MPC has it wrong.  If you Google search 377523 the parts shown are the standard nut with star/tooth washer, and that part number is not correct.  I'll check the assembly manual later and provide an update.

[67gta289]

Jim, your spreadsheet is accurate in terms of part numbers, but I would suggest that two things need some work:

1. For the "TAILLIGHT HOUSING-BODY@TRUNK" nut, there are two line items. I've shown them in yellow in the attached picture.  I believe that the 34653 to be correct, and the 381747 to be incorrect.  If someone else will want to double check on my assessment that would be appreciated.

2. For the studs, shown in blue highlight, we are not sure of the part number for the standard bezel.  You have 381680 listed for the optional lower back panel grille, which I agree with.  Based on the Ford fastener manual, since there is only one type 35 stud listed, and therefore the only one with a thread size of #8-32, I think it is safe to start with the assumption that the lengths would not differ between the standard bezel and the optional panel.  I'll do a bit more research on this later today.

Thanks again for the work on the spreadsheet.  John

[jwc66k]

John,
I've listed both, with appropriate cross references, as 381747-S100 is what Ford Engineering specified, and 34653-S8 as being the one found (i use MEA to indicate "Measured").
The stud, 381680-S36, is used on an optional tail light panel for 67 Mustangs only (other Ford uses are not determined) but is shown as being in the Ford Service Parts system as WW129 (ref 75 MPC Exterior Molding Illustrated Section F PG 2).
Jim

[J_Speegle]

I guess my next step is to comb through the files and see if this is an early/late thing.

I did just that - keeping to just San Jose just to keep a focus on a single plant.

Found no variation on cars without the optional rear taillight panel except for one car on half of one sides taillight and that car had, some place in the past, damage done to that rear area which likely explains the difference in the nuts used
Test sample below spanning from early to late examples

7R1067xx
7R1107xx
7R1244xx
7R1330xx
7R1394xx
7R1547xx
7R1598xx
7R1650xx
7R1669xx
7R1680xx
7R1748xx
7R1824xx
7R1848xx
7R1849xx
7R1883xx
7R2072xx
7R1974xx
7R1977xx
7R2068xx
7R2139xx
7R2345xx

[67gta289]

Thanks Jeff, that was quick!

John,
I've listed both, with appropriate cross references, as 381747-S100 is what Ford Engineering specified, and 34653-S8 as being the one found (i use MEA to indicate "Measured").
The stud, 381680-S36, is used on an optional tail light panel for 67 Mustangs only (other Ford uses are not determined) but is shown as being in the Ford Service Parts system as WW129 (ref 75 MPC Exterior Molding Illustrated Section F PG 2).
Jim

Jim, I did a comparison of a standard bezel and the optional lower back panel grill.  The bosses are the same length.  Since the panel and housing is the same, I would think it is safe to assume that the studs are the same.

[jwc66k]

I did a comparison of a standard bezel and the optional lower back panel grill. 

John,
What are you calling "standard bezel"? I'm using the 67 Mustang Body Assembly Manual, AM0016 pg 36. 
Point of info, I found the full length for 381680-S36 of 2 1/4 in documented in "Ford Standard and Utility Parts Catalog, January 1969, pg 84" and have updated my spreadsheet master file.
Jim

[67gta289]

Jim,
The standard chrome bezel (6 total) is part 13489

The lower back panel grille option (2 total) replace the standard bezels and fill up most of the rear panel.

Pictures included.

John

[jwc66k]

The standard chrome bezel (6 total) is part 13489
The lower back panel grille option (2 total) replace the standard bezels and fill up most of the rear panel.

After seeing your source pictures it gets clearer. First, the stud, 381680-S36 is called out on the Mustang Body Assembly manual for the optional taillight panel only. You found the same stud used on the standard taillight assembly, however the stud is supplied with the complete standard taillight (your reference 13489, full servise part number is C7ZZ-13489-A - to 4/17/68, C7ZZ-13489-B after) and would not be shown in any engineering or service documentation.
Does that make sense?
Jim

[67gta289]

Yes, that makes sense. It is the same conclusion I came to.

[jwc66k]

Yes, that makes sense. It is the same conclusion I came to.

John,
I will add your findings to the master spreadsheet and it will appear in the next release (when I finish some other additions).
Thanks,
Jim

[stangerdude]

I parted out a 67 GT/A fastback years ago that had the rear panels and it had the same nuts as in the third photo of the original post. In fact most if not all of the factory installed rear panels I have seen had those type of nuts. The "standard" chrome bezels all have the nuts shown in Jeff's picture above. I installed those panels from that 67 on my 68 GT (I know not correct for 68 but it is my car and I like them!) Now as a sad side note......the 67 GT/A fastback they came from was rolled by the owners brother 2 weeks after a complete restoration and totaled. Don't drink and drive!!!   Paul

[67gta289]

Regarding the 377523 nut highlighted in the attached picture, the MPC says that this is also used in position "A" of the second picture for mounting the molding on the 68 Mustang quarter panel.

Does anyone have an original 68 molding with hardware laying around?  If so can you provide close up pictures of the nut?

[ruppstang]

Regarding the 377523 nut highlighted in the attached picture, the MPC says that this is also used in position "A" of the second picture for mounting the molding on the 68 Mustang quarter panel.

Does anyone have an original 68 molding with hardware laying around?  If so can you provide close up pictures of the nut?

I do not believe that they could use the same hardware, the tail light housing studs are a machine thread and the quarter ornaments  studs are pot metal that uses a tin nut that cuts its own thread.