kapok c65

1 hour ago, Joey Mack said:

The fluid is likely from a bad wheel seal.  The air brakes are easy to adjust, as long as its not rusted realy bad. How familiar are you with the wheel end parts of air brakes?

I know nothing . Was hoping for a guide to some literature and pictures.  It only did that when I left e brake on . Drove it three times since and no new fluid has shown . What's the proper name for the valve on my firewall in first picture

Good day fellas , I may be on the wrong form but I hope you guys will still help me . I just bout myself a 74 chevy c65 single axle dump truck.  She runs drives stops and dumps so a great little investment.  Stopping She slightly pulls to the right . So I'm wanting to go over them replace brake chambers, adjust slack adjusters just get the system to stop on a dime , or at least straight . Can anyone point me to the right literature on this style of system? I look up air brakes and I get lost . I left what I imagine is my e brake on for for about a mile and I seen it looks like brake fluid leaking on my back tire ? I see no master cylinder? Please point me in the direction to learn more of this system .