I still wasn’t thrilled with the long pedal travel, so I ended up pulling the master cylinder. Turns out, the Dorman M71248 master cylinder does NOT have a residual pressure valve in the port feeding the rear brake lines as it should. Even though it is advertised as being correct for a power disc/drum car.
NOTE: This is the master cylinder West Coast Classic Cougar sells as their “Economy” offering, I left a review on their site so hopefully WCCC and prospective buyers will be aware going forward.
I ended up swapping in a Raybestos MC36251 master cylinder which DOES have a residual valve installed for the rear brake circuit (you can tell if there’s one installed by sticking a paperclip into the brake port. If you feel a spring pushing back there is a residual valve). It was a PITA, but after getting the new master bench-bled, installed, all 4 corners bled and rear brakes adjusted again for good measure the brakes are working really good now. Pedal travel is right where it should be and feels similar to a modern power disc car.
