1937 Brake Pedal Adjustment

[Marshall V. Daut]

As some of you may recall, two years ago I repaired my friend's brake shoe and spring operation on his 1937 Fordor, which he has owned since the mid-1950's. Thanks to advice and parts supplied by the readers on this site, his car has stopped very well since then.
Readers may also recall that a local "repair" shop royally screwed up the brakes on this car. My friend reported that the car stopped worse AFTER he got it back from the shop. Since I repaired the brakes on all four wheels afterwards, my friend has put only a couple hundred miles on the car. I got a phone call a few weeks ago from my aged friend, informing me that he'd had an accident because the brakes completely failed. Upon approaching a stop sign, the pedal had gone to the floor with NO brake action. I PANICKED!!! How could all four wheels have failed at once? This is not a hydraulic brake system, where such a thing could happen. I was sure nothing I had done at the backing plates would have caused this catastrophic brake failure. One wheel, perhaps. But all four??? At the collision repair shop, I pushed on the brake pedal and it did, in fact, go to the floor with zero resistance. Aha! The problem had to lie between the pedal and the rod connection to the main cluster of cable connections. Lying on my back and peering up into the foot well with a trouble light, I saw that the brake pedal pin had backed out of the arm and adjusting clevis so that there was no longer any connection! The pin was just dangling in the brake pedal arm, almost ready to fall out completely. My friend told me the shop had removed the transmission for some unspecified repair at the time the brakes were "fixed". I suspect the Einsteins in the repair shop forgot to put a cotter pin back in the pedal pin. It finally worked itself loose. Fortunately, only the left front fender was damaged, no injuries. A replacement fender was procured and will be painted and installed. All because someone forgot to install a 2 cent cotter pin!
O.K. An easy fix from above - IMPOSSIBLE from beneath. Once I put the pin back into place and hooked up the return spring, all was good. I just need to put in a heavy-duty cotter pin to keep the pedal pin from every working its way back out again. But upon re-assembly, I noticed that the brake pedal travelled quite a ways downward before resistance was felt. See the attached photo. There is a gap up front between the pin in the pedal arm and the adjusting clevis, maybe 1/2"? Should there be this gap or should the clevis be adjusted to remove all or most of this gap? Does the gap need to be there for the emergency brake operation? Why such a looooong clevis adjustment area? I don't trust ANYTHING the "repair" shop did to this poor car, so I wouldn't rule out misadjusting this clevis. What is the proper adjustment at this point, please?
My expertise is Model A's and T's, so each thing I do on my friend's car is new frontier for me. 'Sorry if this question is too basic.
Thanks in advance.
Marshall