01’ Pete 379 Weak Brakes

First thing I'd do after verifying proper brake adjustment and free movement of the cams is plumb a gauge in at each brake chamber and see if you're getting the proper application pressure at each wheel.

 

I would agree with looking into the treddle valve as suspect if all of the foundation brakes are in order. More importantly check the plunger under the boot at the pedal mount. Older trucks these get all gummed up and corroded and some plain sieze right up. Be aware if its bad under there you may end up replacing it all before you are done depending on the level of corrosion, bolt breaking ect.......

If it were mine, get all the parts ahead of time. Worse that happens is you return some if you dont need em all.

 

Mine was doing that, then it would stick with brakes applied, till I stabbed it hard, to release them. Especially in cold weather. I sprayed it real good with Pb blaster. I’m told you can remove the plunger and clean, or replace it. I couldn’t figure out how to do it. Mines been working good, but still a little grabby. I’m going to just replace the whole foot valve, before winter. I hear it makes braking very smooth. Like new.

 

With the treadle being so critical to controlling the brakes, I'd toss the entire assembly, pedal and all, in the trash if it is what is causing the issue.

 

Thank you gentlemen.