Help - Rear brake drum size....how can i tell..

[bs549]

how can I tell what size rear brake drums do I have on mu 74 Cuda?  Where do I measure at on the drum to determine the size?  The drum has a stamping number of 35536.

Thanks!

[ShelbyDogg]

You either have the 10" (nice, smooth outer drum)
or the 11"x2-1/2 (Big Finned outide edges) You can't miss the fins.  They usually came with the big 11" drum brakes in the front.
Most disc brake cars came with the 10".

Mine still has the Huge rear drums because I converted the front to disc.
By 74 almost everything was 10"

[bs549]

Mine are smooth, and the car originally came with front disk brakes, so I've got the 10" for sure.   Thanks for your help!

[ShelbyDogg]

My '72 340 Cuda came with Fron disc AND with the 11" finned rear drums. To measure the drum/brake diameter, you take off the drum and measure across the drum face that the brake shoes stop against.
Rob

[FRITZ]

Are the drums on an AAR 11x21/2?

[Chryco Psycho]

measure the drums , across the inside of the drum wheret he shoes run against , I ran into a set of smooth 11 X2.5" drums just today

[Alaskan_TA]

AAR drums should be the finned style for sure and I believe 11" x 3" ?

If I get a chance I will pull one of mine and check......

[Alaskan_TA]

I could not stand it, I had to check. The braking surface in the drums does measure 3" but they use 2.5 inch pads.

Barry

[Chryco Psycho]

ok I have a customer with a 11 X 2.5" drum & shoes on the rear of a 68 RR , the drums are smooth like the 10 " , I suspect they are not original  , any guesses on the real application

[ShelbyDogg]

Maybe those were aftermarket replacements?  I've never had to buy a drum because I always had originals laying around.

I've never seen any 11"x3" drums on the rears of cars, Only on the fronts.  Had them on my Challenger, but had to change them to discs in the '80s after a 100+Mph brake fade incident.
11x3 fronts, 11x2.5 rears.
Those big front drum brakes were only good for adding weight to the fronts of our cars.