Author Topic: Converting to the Shelby 2 1/2" drums on early mustangs  (Read 6935 times)

gt350hr

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #15 on: March 23, 2022, 05:28:56 PM »
  If the hole is too small it can be opened. Too big is a no no.
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mlplunkett

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #16 on: November 21, 2022, 06:27:31 PM »
Thought I'd throw this out there for those who may want to follow the spirit of the Shelby modification but but not necessarily the letter of the law. I got this off a mustang forum that was trying to solve the same problems we are. If 11x2.25 is close enough to 10x2.5 then a complete kit including loaded backing plates and parking brake components with your choice of "racing" or "street performance" shoes is available for less than $500 at https://opentrackerracing.com/shop/11-x-2-25-drum-brake-for-small-bearing-ford-rear/ . I gotta say that looks pretty attractive for a tribute car.
« Last Edit: November 21, 2022, 06:31:22 PM by mlplunkett »
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68stangcjfb

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #17 on: November 21, 2022, 08:50:24 PM »
Those are 1979 to 1990 LTD Crown Victoria rear brakes from a station wagon, or a police car. I have them on my Fairlane station wagon and I took them off a 1984 Ford full size station wagon. You can probably get them at a junkyard for a lot less money.
68 1/2 CJ Mustang GT FB auto 3.91s, 68 1/2 CJ Torino GT FB 3.91s, 60 Thunderbird, 64 Falcon Sprint conv. 4Spd, 65 Falcon Sedan Delivery, 67 Fairlane 500 SW 428 4Spd, 68 Torino 4dr, 95 Thunderbird SC. 89 F250 Supercab 2wd, 99 Sable, 99 Jeep Cherokee, 2002 Thunderbird. 96 Harley FLSTN Heratige Special

SFM6S

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #18 on: January 26, 2023, 08:57:37 AM »
The Ranger drum mentioned above has a centering bore of 2.808 inches. 3/8" inches larger that a vintage drum. perhaps a sleeve could be swaged on the axle hub to accommodate for the difference.
Joe

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #19 on: January 26, 2023, 04:29:47 PM »
Google hub centric rings. They make them in lots of different sizes and if you can't find one the right size there are places that make custom ones. You can get them in plastic or metal.

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mlplunkett

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #20 on: February 02, 2023, 06:51:15 PM »
Found a pretty good article on the vintage mustang forum

https://mustangsandmore.com//ubb/RearBrakesbySamGriffith.html

Found a good video on Youtube

https://www.youtube.com/watch?v=IVNfHXiqAgA
« Last Edit: February 02, 2023, 07:20:17 PM by mlplunkett »
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roddster

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #21 on: September 26, 2023, 05:55:58 PM »
Late news.  I found this out recently.
  Bought what was advertised on Ebay as backing plates for the 10" by 2 1/2" rear brakes.  Not so.  The drum ends at the edge of the backing plate with about a 1/8" gap between the plate and the drum.
  Bendix # 320 9029-R/320 9028-L. DO NOT USE THESE
   Bought these on Ebay like 6 years ago.

  One other thing:  that motor trend article doesn't say a word about the backing plate offset.
« Last Edit: October 08, 2023, 12:07:58 PM by roddster »

roddster

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #22 on: October 08, 2023, 12:11:18 PM »
  After spending a few hours at a U-Pick yard, taking measurements and such, rule out the Ford Ranger pick-up backing plates as a viable option.  Same measurements as above.  Looked at 95's, 99's, 2000's. 4 X 4 and two wheel drive. Ain't gonna work.
  And here in the rust belt, there are NO Fomoco products earlier than 1990.

shelbymann1970

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #23 on: October 09, 2023, 08:26:06 AM »
What about F-150 rear drum brakes? I remember hearing this was another way to upgrade the rear drum brakes.

On my 69 SCJ Mach 1, I used early 1960's Galaxie rear drum brakes for more brake capacity, as the rear drums did very little. It was a bolt-on to the 9" housing.

Remember - Once you do this upgrade, your brake system balance and pedal bias WILL change. There are calculations to determine the needed M?C bore and stroke. When I did mine, I ended up swapping to one from a 1960's Ford dump truck. Then the upgraded system was good! Still on the car to this day with it's new owner.
Yep, that setup still works great on Dan's old car. I believe the M/C is a F650 model? Of course since Dan and his Ex used to use my car at SAAC track events he installed a proportioning valve behind the rear seat and adjusted it accordingly for high speed braking.
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roddster

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Re: Converting to the Shelby 2 1/2" drums on early mustangs
« Reply #24 on: December 14, 2023, 05:41:10 PM »
  My final Update as I figured it out for my tribute car
 12/14/2024

  Here is what I have: backing plates # 3209029/3209028 (Bendix). I have no idea what Fomoco product it is off as I bought them about 6 years ago on Ebay.  A U tube video suggested to use backing plates from an 85' Full size Ford.
  The usual refrain is to use Ranger rear drums, but those leave a 1/8" gap between the backing plate and the drum.  Not going to work. 
  I ran into a U tube video and the person said to close the gap, buy rear drums that are from a 69 Cyclone with a 428.
 These are part number 1639R (Raybestos).  Rock Auto had these and yes, the gap is closed and fits correctly.  So, there you go, this is what works.  BUT: seems these drums are about 3 pounds heavier than the Ranger drums.  At least you get the larger swept braking area.  Go figure: it's 3/4" wider times 10" Pi.
  Small issue with the drum.  Just like on the Ranger drum, there are raised cooling fins along the entire perimeter of the Cyclone drum.
   Hint: also seems that the brake combi kit (that's the return and hold down springs folks) come with the pins that hold down the shoes are a little short.  The correct pin length for the 2 1/2" shoe is 2 15/32".  You can order those at the local O'reilly's.
  Had a conversation with a popular East Coast parts supplier.  They informed me that the people who were stamping the backing plates for them went out of business.  They were looking for a new supplier.