I'm fairly new to these "soft fender" trucks. I'm used to the ones that you can use a front fender to knock down a tree without damaging the fender. I, too, cannot find useful details in my "soft fender" FSM, but the description in this thread makes me think I have what you need.

Go to www.texaspowerwagon.com and scroll down to "Brakes" in the Frequently Asked Questions section. I have scanned the section of a "flat fender" FSM that covers these brakes. You can download and print out your own brake manual - handy if you actually use a manual. Print it out. Use it. Get it dirty. Throw the dirty one away. Print out another.

While you are at the Kempner Power Wagon Museum web site, check out my '67 W100. It is my first "soft fender" and I am spending a lot of time over here at the '61-'71 Dodge Sweptline Truck Forum learning stuff about it.

While you are here, notice there is more than one Dodge forum. Each has many things that you might find useful.

I hope this helps.