Rear brakes on a 68 390 GT; 2" drum or 1 3/4"

Cougar Community Classic Cougar Maintenance Restoration and Repair
1

Right now I am a bit confused. I am having a little fun with a 68 Cougar XR7 390 GT and when I took apart the rear brakes I noticed that the car has the 1 3/4" wide drums. I was a little surprised to see that this car has smaller brakes than my 68 XR7-G Hertz and also smaller brakes than my 68 XR7 with a 302 engine. When I looked closer at the drums on the car I noticed that they had been replaced and started wondering if someone had replaced both drums and brake shoes with smaller Mustang brakes. Well, a quick check in my parts manual showed that both sizes were available for the Cougar, but it does not tell what models or engines the different sizes were used for.
Now I wonder if it possible that a 390 GT Cougar could get the smaller brakes from factory? :question: :question:

2

It should have 2" brakes. Perhaps someone swapped the entire brake drum / backing plates as an assembly years ago.

3

Thank you Royce, that’s exactly what I was thinking at first as well, then I started to wonder… I have not checked if the backing plates have been swapped as well, I will do that tomorrow. What I know is that the rear end has the correct tag for the car.

4

Do you have narrower drums or just the smaller shoes?
1 3/4" shoes will somewhat fit and work in place of the 2", you’ll have an area of the drum that the shoes never contacted.
My cat had 1 3/4" shoes, should have had the 2"

5

I just checked, the backing plate, shoes and drums are all 1 3/4".

6

i could be real wrong but all the spec i’ve seen for a 67 (390) show a 1 3/4 shoe—i think it was done to keep the rears from locking up—the fronts have so much weight that the fron traction is great----i questioned the books when i did colleens car also
doctordesoto

7

This is what Wagner brakes has to say.
Brake Shoes - ThermoQuiet
PAB169R BASE MODEL; Front; 10 x 2-1/2" Brake; Riveted 1
PAB169R XR-7; Front; 10 x 2-1/2" Brake; Riveted 1
PAB151R XR-7; Rear; 10 x 1-3/4" Brake; Riveted 1
PAB151R BASE MODEL; Rear; 10 x 1-3/4" Brake; Riveted 1
PAB169R BASE MODEL; Rear; 10 x 2-1/2" Brake; Riveted 1
PAB169R XR-7; Rear; 10 x 2-1/2" Brake; Riveted