The Boss 302/TransAm racing T-Bird big brake caliper bracket dilemma,
Or
The big brake caliper bracket eureka moment at the turn of the century!
Is that a long enough title?
Anyway. After posting some spare parts I had on the shelf for many years for the Boss 302/TransAm racing T-Bird big brake set-up, I got a lot of questions asking if I had all the parts for the set-up.
So I went looking through more boxes and crates.
I am a sick person. I have parts for parts that I didn't know even needed parts. Parts I didn't even know/remember I had, when I got them or where I got them from. Too many projects under the bridge. Well under the bridge is where I found more boxes. Sort of.
But enough about my neurosies.
The part everyone considers the holy grail of the Boss 302 TransAm big brake set-up is the T-Bird big caliper bracket that attaches to the 1970 Mustang drum brake big spindle setup.
Well guess what? I don't have those brackets. Surprise. Surprise.
But what I have is the result of the big brake caliper bracket eureka moment at the turn of the century, OK, the late 1990's early 2000's.
In the 1990's I was helping a good friend build up a 1970 Mustang as a Boss 302 clone for "club racing" and test session fun at Willow Springs. Being a clone build and a low budget project to boot, parts were scrounged from friends, back yards, and wreckers. But the big brake caliper bracket proved elusive. This may have been before Cobra Automotive offered a bracket, or maybe we just didn't want to spend the money.
But we had the internet. And luckily we stumbled on some Ford/Mustang website where this very problem was being kicked around. Was the big brake caliper OEM from Ford the only solution?
Disclaimer! I am not taking credit for the following innovative and imaginative solution. My old notes say a website poster with the handle "1RadRod" came up with this.
The genesis of the Boss 302 big brake caliper kit is well known. Kar Kraft, Bud Moore and others scoured the Ford parts book and came up with the solution and Ford Racing/Kar Kraft Engineering came up with a new caliper bracket. But was it new? Unique to thisTransAm application for sure. But the design concept – was it new?
Perhaps not.
If you compare the Boss 302 big caliper bracket with a 1965 to 1967 Mustang regular production caliper bracket they are remarkably similar. In fact the same where it attaches to the spindle, but different for the spacing of the caliper mount pedestals – wider apart for the bigger T-Bird calipers. Were the big caliper brackets thicker or stronger. I don't think so, but I don't know for sure. Seems to me there would be more stress risers in the big caliper bracket with those caliper pedestals hanging out there.
See pic 1 below as an attachment(I still can't figure out how to insert a pic into this text)
So what was "1RatRod"s solution?
A simple but effective use of steel bar stock commonly found in any shop. (or McMaster Carr ).
A ½" thick by 1.25" wide by 6" long steel bar "bridge" was fabricated and drilled (see pics) that attached to the caliper bosses on the existing spot faced surface using the existing 9/16" tapped bosses in the caliper.
Then a 5/8" thick by 1" wide by approx. 3.75" long "bridge support" was fabricated and drilled to match the narrower 65-67 Mustang regular production caliper bracket 7/16" holes mounting holes. (see pic 2 below)
The two are then welded together to form a very rigid "T" shaped "bridge bracket". (see pic 3 below)
The caliper does not need to be spot faced on the back side of the caliper threaded attachment bosses since the OEM T-Bird caliper attaching face is used as originally purposed. (see pic 4 below)
In fact, any fine tuning to centering the caliper (in and out) on the rotor can be done with shims.
And the "bridge bracket" can be sized/positioned to accommodate the positioning of the original 68 T-Bird rotor on the inside of the hub (as we did) or the Coleman rotor/hat assy on the outside of the hub. It's just a matter of sizing the steel bars and positioning the "bridge bracket" relative to the attachment bosses on the stock Mustang caliper bracket.
Easy ( a couple of hours work), cheap ( about $25 for 4 pieces of 6"bar stock from McMaster Carr) and strong.
This solution worked just fine.
Eloquent in its simplicity.
I'm interested in your comments.
But let me go make some popcorn made before the comments start flying.
Cheers
Greg
PS. I'll be posting the complete set up I have for sale in the SAAC classifieds.
Or
The big brake caliper bracket eureka moment at the turn of the century!
Is that a long enough title?
Anyway. After posting some spare parts I had on the shelf for many years for the Boss 302/TransAm racing T-Bird big brake set-up, I got a lot of questions asking if I had all the parts for the set-up.
So I went looking through more boxes and crates.
I am a sick person. I have parts for parts that I didn't know even needed parts. Parts I didn't even know/remember I had, when I got them or where I got them from. Too many projects under the bridge. Well under the bridge is where I found more boxes. Sort of.
But enough about my neurosies.
The part everyone considers the holy grail of the Boss 302 TransAm big brake set-up is the T-Bird big caliper bracket that attaches to the 1970 Mustang drum brake big spindle setup.
Well guess what? I don't have those brackets. Surprise. Surprise.
But what I have is the result of the big brake caliper bracket eureka moment at the turn of the century, OK, the late 1990's early 2000's.
In the 1990's I was helping a good friend build up a 1970 Mustang as a Boss 302 clone for "club racing" and test session fun at Willow Springs. Being a clone build and a low budget project to boot, parts were scrounged from friends, back yards, and wreckers. But the big brake caliper bracket proved elusive. This may have been before Cobra Automotive offered a bracket, or maybe we just didn't want to spend the money.
But we had the internet. And luckily we stumbled on some Ford/Mustang website where this very problem was being kicked around. Was the big brake caliper OEM from Ford the only solution?
Disclaimer! I am not taking credit for the following innovative and imaginative solution. My old notes say a website poster with the handle "1RadRod" came up with this.
The genesis of the Boss 302 big brake caliper kit is well known. Kar Kraft, Bud Moore and others scoured the Ford parts book and came up with the solution and Ford Racing/Kar Kraft Engineering came up with a new caliper bracket. But was it new? Unique to thisTransAm application for sure. But the design concept – was it new?
Perhaps not.
If you compare the Boss 302 big caliper bracket with a 1965 to 1967 Mustang regular production caliper bracket they are remarkably similar. In fact the same where it attaches to the spindle, but different for the spacing of the caliper mount pedestals – wider apart for the bigger T-Bird calipers. Were the big caliper brackets thicker or stronger. I don't think so, but I don't know for sure. Seems to me there would be more stress risers in the big caliper bracket with those caliper pedestals hanging out there.
See pic 1 below as an attachment(I still can't figure out how to insert a pic into this text)
So what was "1RatRod"s solution?
A simple but effective use of steel bar stock commonly found in any shop. (or McMaster Carr ).
A ½" thick by 1.25" wide by 6" long steel bar "bridge" was fabricated and drilled (see pics) that attached to the caliper bosses on the existing spot faced surface using the existing 9/16" tapped bosses in the caliper.
Then a 5/8" thick by 1" wide by approx. 3.75" long "bridge support" was fabricated and drilled to match the narrower 65-67 Mustang regular production caliper bracket 7/16" holes mounting holes. (see pic 2 below)
The two are then welded together to form a very rigid "T" shaped "bridge bracket". (see pic 3 below)
The caliper does not need to be spot faced on the back side of the caliper threaded attachment bosses since the OEM T-Bird caliper attaching face is used as originally purposed. (see pic 4 below)
In fact, any fine tuning to centering the caliper (in and out) on the rotor can be done with shims.
And the "bridge bracket" can be sized/positioned to accommodate the positioning of the original 68 T-Bird rotor on the inside of the hub (as we did) or the Coleman rotor/hat assy on the outside of the hub. It's just a matter of sizing the steel bars and positioning the "bridge bracket" relative to the attachment bosses on the stock Mustang caliper bracket.
Easy ( a couple of hours work), cheap ( about $25 for 4 pieces of 6"bar stock from McMaster Carr) and strong.
This solution worked just fine.
Eloquent in its simplicity.
I'm interested in your comments.
But let me go make some popcorn made before the comments start flying.
Cheers
Greg
PS. I'll be posting the complete set up I have for sale in the SAAC classifieds.