SAAC Forum

The Cars => 1966 Shelby GT350/GT350H => Topic started by: 6s1640 on March 28, 2021, 01:53:08 AM

Title: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: 6s1640 on March 28, 2021, 01:53:08 AM
Hi all,

Does anyone know when this additional return spring was added with the C6ZZ-7540-A bracket added to firewall.  I believe it is a mid to later 66 Mustang/Shelby both 6 and 8 cylinder.  This would be a San Jose part, not Shelby unique, but all later manual transmission GT350's should have for sure.  Does anyone reproduce this part?  The spring is reproduced.

Thanks

Cory
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: Jbarela on March 28, 2021, 06:04:52 AM
Hi Cory,
Are you looking for one?
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: GT350Lad on March 28, 2021, 06:10:21 AM
Hi Cory, I can have a look at #373 and take some pics. I have all original Z bar and spring set up including original Z bar.

Let me know

Cheers
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: Bob Gaines on March 28, 2021, 11:38:49 AM
Quote from: 6s1640 on March 28, 2021, 01:53:08 AM
Hi all,

Does anyone know when this additional return spring was added with the C6ZZ-7540-A bracket added to firewall.  I believe it is a mid to later 66 Mustang/Shelby both 6 and 8 cylinder.  This would be a San Jose part, not Shelby unique, but all later manual transmission GT350's should have for sure.  Does anyone reproduce this part?  The spring is reproduced.

Thanks

Cory
I think Brant at Virginia had some of the fire wall brackets and correct springs at one point.
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: Jbarela on March 28, 2021, 01:06:16 PM
Hi again Cory, during our restoration hi and low I could not find anyone who was reproducing this part. This is a quote from my dear good friend.
"They are shown as being effective from 2/14/66 to the end of the 66 model year for all manual transmissions. No other information is given. My sources are the 60-68 Ford Car Parts, and the 75 edition of Ford Car Parts."
I have some engineering specs on it if you need it and plenty of pics. When we restored our car we noticed the body man lost the clip when we tried to connect the spring, by chance we found one off a donor parts car.
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: EdwardGT350 on March 28, 2021, 01:29:01 PM
this part can easily fall inside and may be found behind the carpet.
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: 6s1640 on March 28, 2021, 01:41:28 PM
Quote from: Jbarela on March 28, 2021, 06:04:52 AM
Hi Cory,
Are you looking for one?

Hi Jimmy,  Yes, I am looking for one.  I didn't know it until I learned about the 2-14-66 date.  The 1975 MPC does not show a date.  This has been very helpful.

Thank you all

Cory
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: Jbarela on March 28, 2021, 02:22:49 PM
Am I allowed to post the specs here? Or should I just email you? For the life of me I dont know how to attach pics to PMs but I know how to drive our shelby the way it was meant to be driven!
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: s2ms on March 28, 2021, 02:23:40 PM
Hi Cory,

Worse case you can easily fabricate one. I made a crude drawing with dimensions from my original, let me know if you're interested and I'll look for it and send it to you. There are two small "tangs" that help prevent it falling out that I did not include as part of the drawing, mainly because they would be harder to replicate IMO and can't be seen when installed anyway. Plus, as Ed mentioned, they don't work very well anyway. There is also a very small gasket for the bracket, rubber I think, that is not shown in the MPC drawing.

Dave
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: Jbarela on March 28, 2021, 02:32:48 PM
Here is what I have..it is a stamped steel piece I believe. The rubber seal was really thin.
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: Jbarela on March 28, 2021, 02:36:44 PM
The bent tangs. On opposite sides.
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: J_Speegle on March 28, 2021, 02:54:18 PM
Surveys of cars appear to support the possible Feb date listed though we can't be certain IMHO that it was a hard date and that they removed all the earlier firewalls from the line and plant. But we will likely never know for sure since we can't tell when each of our cars were really finished

On cars that were automatics (same firewall was used for all cars 6 and 8 cylinder as well as both transmission styles) the unused hole was first covered with a section of tape applied to the inside of the car and very soon after that a rubber plug made for this purpose

For some addition pictures and information here are a couple of links

http://www.concoursmustang.com/forum/index.php?topic=23645.msg152114#msg152114 (http://www.concoursmustang.com/forum/index.php?topic=23645.msg152114#msg152114)

http://www.concoursmustang.com/forum/index.php?topic=23641.0 (http://www.concoursmustang.com/forum/index.php?topic=23641.0)
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: jk66gt350 on March 28, 2021, 03:14:37 PM
6S1575 with an estimated mid to later March '66 San Jose production date has neither the firewall bracket or hole drilled in the Z bar for an upper clutch spring. 
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: Jbarela on March 28, 2021, 03:48:51 PM
Quote from: jk66gt350 on March 28, 2021, 03:14:37 PM
6S1575 with an estimated mid to later March '66 San Jose production date has neither the firewall bracket or hole drilled in the Z bar for an upper clutch spring.
that's interesting 6s1902 estimated 3rd week of march has all the provisions for it and of course the parts.
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: J_Speegle on March 28, 2021, 04:50:15 PM
jk66gt350  did add yours to the list/survey as I didn't have a picture of that area of the car. Would likely make it the second to the latest example I have on record

Quote from: Jbarela on March 28, 2021, 03:48:51 PM
Quote from: jk66gt350 on March 28, 2021, 03:14:37 PM
6S1575 with an estimated mid to later March '66 San Jose production date has neither the firewall bracket or hole drilled in the Z bar for an upper clutch spring.
that's interesting 6s1902 estimated 3rd week of march has all the provisions for it and of course the parts.

Of course its all about the Ford VIN and when those bodies/cars were completed.  And of course many of us are using different methods of guessing when a particular car was finished - not shipped from San Jose. This is also assuming that we're all looking at unrepaired and unreplaced panels

As mentioned in the link I posted I've came up with the following from my records and pictures.

"- Earliest (Lowest VIN) example with the hole 6R1639xx  Early enough to not have the rubber plug for the hole used

- Latest (highest VIN) example without the hole 6R1789xx"
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: jk66gt350 on March 28, 2021, 06:33:30 PM
The VIN on 6S1575 is 6R09K176XXX.  Firewall area has never been messed with.  Almost all dates on the car's parts, panels, glass etc. are either January or February 66.  The latest date I found is a mid March date for one of the hood hinges.  I estimated the production date based on production numbers by week that was published on 66 Mustangs.   John
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: greekz on March 28, 2021, 07:31:51 PM
I believe 6S1134 to be and early February 1966 at SJ, as the engine assembly date is 6A27.  It was shipped from SA on February 28.  It has no firewall bracket or hole in equalizer bar.

Hope this helps.

Greek
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: s2ms on March 28, 2021, 08:01:25 PM
Quote from: Jbarela on March 28, 2021, 02:32:48 PM
Here is what I have..it is a stamped steel piece I believe. The rubber seal was really thin.

Thanks Jimmy, that's my drawing, saved me from having to look for it!
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: Jbarela on March 29, 2021, 12:26:46 AM
Quote from: s2ms on March 28, 2021, 08:01:25 PM
Quote from: Jbarela on March 28, 2021, 02:32:48 PM
Here is what I have..it is a stamped steel piece I believe. The rubber seal was really thin.

Thanks Jimmy, that's my drawing, saved me from having to look for it!
lol, what are friends for. Now let's see who can fab these. Not an easy part to find when you need it.
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: NC TRACKRAT on March 31, 2021, 04:25:19 PM
Well, it's a rainy day and I like a challenge.  Yes, they can be fab'd. Took me less than an hour.  No, I will not go into production.  But, if anyone is interested, I'll be glad to furnish instructions and material selection. 
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: 6s1640 on April 06, 2021, 11:25:05 PM
Well, finding this bracket is proving to be impossible.  So I have tinkered with making one from the sketch provided on this thread.  This prototype was just to see if I could make anything close, eyeballing the features, not per drawing.  The trick was deriving a method for the two barbs.  It has turn out well enough that I should be able to make one pretty close to original.  This piece was made from thicker 16 gauge galvanized steel.  I am looking at ordering some stainless in the 17 gauge, very close to the .057 dimensions given.  I will trying to also find just plain steel in the 17 gauge, more like OEM.  Thanks for you help.

Cory
Title: Re: C6ZZ-7540-A Clutch Return Spring Bracket on Firewall
Post by: Jbarela on April 07, 2021, 01:08:39 AM
Quote from: 6s1640 on April 06, 2021, 11:25:05 PM
Well, finding this bracket is proving to be impossible.  So I have tinkered with making one from the sketch provided on this thread.  This prototype was just to see if I could make anything close, eyeballing the features, not be drawing.  The trick was deriving a method for the two barbs.  It has turn out well enough that I should be able to make one pretty close to original.  This piece was made from thicker 16 gauge galvanized steel.  I am looking at ordering some stainless in the 17 gauge, very close to the .057 dimensions given.  I will trying to also find just plain steel in the 17 gauge, more like OEM.  Thanks for you help.

Cory
that's a pretty good job Cory. Still hunting one down for you.