Topic: Spring Shackle Differences

[67350#1242]

I'm looking for info on differences in leaf spring shackles.   Questions are:
1.  Were there different shaft diameters between early and later cars? (I've seen 1/2" and 9/16" advertised)
2.  Any difference in lengths?  Width?
3.  Were the ones marked C6DA San Jose only, and what years would these be found on?
4.  Would the special dual exhaust LH shackle be marked with a part number? ( 67 San Jose car)
Any other specific information?

Thanks for any info you may contribute.     Kurt.

[jwc66k]

1.  Were there different shaft diameters between early and later cars? (I've seen 1/2" and 9/16" advertised)

Yes, 64 and 65 had 9/16 inch diameter shafts. 66 on were 1/2 inch diameter. A NPD catalog would define this.

2.  Any difference in lengths?  Width?

Should be the same length, but there may have been difference in width between different suppliers.

3.  Were the ones marked C6DA San Jose only, and what years would these be found on?

I assume all plants as the part number is not plant specific and is used on Falcons and Mustangs and maybe more (Comet?) thru at least 1969 (per 75 MPC service kit).

4.  Would the special dual exhaust LH shackle be marked with a part number? ( 67 San Jose car)

The only marking I've found on any shackle was the C6DA on the standard bar.
What are you looking for?
Jim

[Bob Gaines]

I'm looking for info on differences in leaf spring shackles.   Questions are:
1.  Were there different shaft diameters between early and later cars? (I've seen 1/2" and 9/16" advertised)
2.  Any difference in lengths?  Width?
3.  Were the ones marked C6DA San Jose only, and what years would these be found on?
4.  Would the special dual exhaust LH shackle be marked with a part number? ( 67 San Jose car)
Any other specific information?

Thanks for any info you may contribute.     Kurt.

1/2 inch shaft is typical on a 67. There are no difference in lengths or widths 67-70 with the slight exception of the slightly different shape of the C6DA marked plate used in 67. Although the shackles will interchange 65-70 the 65/66 are a slightly different shape. The C6DA shackle was used in multiple plants in 67 as far as I know. There is no part/engineering number on the LH duel exhaust shackle just like there is not part/engineering number on the RH side. Also something to note is that the service shackles typically use a thicker metal then the assemblyline . I think the service parts used this improved version starting with 70 and newer made service parts. 69 production cars still used the thinner steel shackle.

[67gta289]

The MPC of course won't show any deviations between manufacturers or assembly plants.  But here is what they do indicate. All of this information is from the 60-68 MPC

Ford part 5630 is a "Kit - Shackle" and contains the multiple individual parts that make up the shackle.

Kit C4DZ-5630-B is for 65 Mustangs (only) and includes a C4DA-5627-A Bar and C4DA-5776-A Shackle and stud assembly along with bushings and nuts.

Kit C6DZ-5630-A is for 66-68 Mustangs and includes a C6DA-5627-A Bar and C6DA-5776-A Shackle and stud assembly.

It is interesting that for the 1966 289 Special (HiPo) it calls for only one of these, with a right hand only application note.  There is no mention of the left hand side which leaves us wanting and wondering, as is sometimes the case with the MPC.

The 5627 "Bar - rear spring shackle - rear" and 5776 "Shackle assy - rear spring - rear" were not serviced separately.  The bushings themselves were available separately.

It is also interesting to note that the 67 one year only MPC (January 1967) does not list any service shackles for the Mustang.

This provides some supporting information for Jim and Bob's responses.  The 65-72 MPC has no changes to the aforementioned kits.

[67350#1242]

Wow!  Thanks for the very quick and precise rundown - answers all my ?'s.

Looks like the special LH shackle for dual exhaust was never serviced.
My 67 GT350 had regular shackles on both sides - I was thinking of trying to make one of the LH's and wanted to know what to look for to reproduce it from orig. parts, but at this point I may leave it as is because I really don't have strong evidence that it came with one.

Thanks again - Kurt.

[Bob Gaines]

Wow!  Thanks for the very quick and precise rundown - answers all my ?'s.

Looks like the special LH shackle for dual exhaust was never serviced.
My 67 GT350 had regular shackles on both sides - I was thinking of trying to make one of the LH's and wanted to know what to look for to reproduce it from orig. parts, but at this point I may leave it as is because I really don't have strong evidence that it came with one.

Thanks again - Kurt.

Kurt , you can do what you want because it is your car however your shackles were most likely replaced at one point. The mostly purchased kits came with shackles and bushings so that is why they get replaced with different many times. Every survivor 67 Shelby that I have ever inspected had the duel exhaust only LH shackle. That is not to say somewhere somehow one might have gotten missed by mistake however it was typical for them to have them. Given 65-67 duel exhaust typically was engineered to get the shackle (assemblyline manual supports observations) and 68 up did not when you see a 67 Shelby without what is more likely that it got changed out or a Factory mistake?

[Bob Gaines]

FYI the C6DA marking was not seen on the LH shackle.

[67350#1242]

Bob, thanks that does make sense.  So I should find a set of originals with 1/2" shafts and not worry about the eng. number.
If I press one shaft out of each side I should end up with a good representation.
Alternatively, NPD sells a repro of the shackle but looks like the plating on shafts are zinc rather than a heat treated look.  Do you think that this repro could be modified to create a passable piece, or are there other differences that would be telltale as not original?
Which way would you go?

[jwc66k]

So I should find a set of originals with 1/2" shafts and not worry about the eng. number.
If I press one shaft out of each side I should end up with a good representation.

You take two sets with shafts, press out one shaft of each, drill out the pressed out hole to the size of the hole in the bar and you are in business.

So I should find a set of originals with 1/2" shafts and not worry about the eng. number.

The marking is on the bar only, which is right hand use only.

Alternatively, NPD sells a repro of the shackle but looks like the plating on shafts are zinc rather than a heat treated look. 

Many years back, in making a "set" of shackle for one of my dual exhaust cars, I found the finish of the shafts to be clear zinc plated. This was before reasonable reproductions were available. Make your own conclusion.

Do you think that this repro could be modified to create a passable piece, or are there other differences that would be telltale as not original?

I didn't find any visible differences.
Jim

[Bob Gaines]

Bob, thanks that does make sense.  So I should find a set of originals with 1/2" shafts and not worry about the eng. number.
If I press one shaft out of each side I should end up with a good representation.
Alternatively, NPD sells a repro of the shackle but looks like the plating on shafts are zinc rather than a heat treated look.  Do you think that this repro could be modified to create a passable piece, or are there other differences that would be telltale as not original?
Which way would you go?

Although you can do some doctoring of the NPD shackle it will never look as good all things being equal to one made up from original parts IMO. It has always been easy to tell . Keep in mind that the side you press out will leave a hole too large.You can put a washer on the backside that is the thread size which will not pass the 1/2 shaft however the large hole will barely catch the nut when you tighten it down. That would be a safety issue. You can see the the larger hole with the nut barely catching too.You have to weld up the hole and redrill to size making sure that the exposed side is dressed out presentably. The best way and less work is to use two side plates drill the hole for the 1/2 shaft (slightly smaller so it can be pressed in and hold) in each and install the shaft. The down side is that it is more parts to source.It can be difficult to find just the one plate separate so you typically have to buy both sides to get the one side you need for the conversion.In this case 68 or 69 cores will work for the purpose of the conversion.

[jwc66k]

Keep in mind that the side you press out will leave a hole too large.

Yup, you got that part correct. You need to drill the bar piece to accept the larger diameter shaft, but small enough for the serrations to grab metal. I got the drilling part correct, but picked the wrong side. And don't use a bar marked C6DA.
A correction, there are vendor IDs stamped into the metal.
Jim

[67350#1242]

Good info - thanks for the tips
Kurt

[gjz30075]

Be careful of the NPD LH shackle.   I bought one recently and it is half the width of an OEM shackle.   My, what I believe is OEM, shackle measures 1/4" width.   

[67gta289]

Are you talking about a 1/4" thickness of the steel?  I can measure some later but that sounds way too thick to be OEM based on my recollection.

[gjz30075]

Yes, thickness of the steel.    I have several known aftermarket ones, all shaped differently than this one, and all measure 1/4".   I'm anxious
to know what you find.  Thanks.

edit:  .226, measured with calipers, to be more precise.   .156 is the measurement of the NPD piece