Brake pedal push rod questions.

[ahawes]

I've got an 89 crew cab one ton single rear wheel (old body style) truck. When pulling out of the driveway the other day somehow the brake pedal push rod came out of the master cylinder side of the works. After an embarrassing romp on the e-brake and skid I got the truck back into a parking spot. When trying to get the rod back into the hole on the master cylinder I ended up having to open a bleeder up to relieve enough pressure to get it compressed enough to fit in. I still have no idea how this even happened in the first place but it is fixed for the most part now so it is what it is.

The question I have is this: My brake pedal push rod has a slot on the end that goes into the master cylinder side maybe 1/4-1/2" back from the very tip. In this slot was a pin that very easily fell off when I reached up there to see what was going on when I lost brakes. It seems as though the whole load of braking in the truck would be carried by this pin and I can't understand why that would be the stock setup. Is this something that has been rigged up poorly by a previous owner or is this how they all came? I've tried to find a diagram or picture of any sort online but the results are basically non-existent. Would anyone with a similar truck be willing to feel up there to see if this is what is in their truck as well? Any help would be greatly appreciated.