Originally Posted By an8sec70cuda
What does the belt have to do w/ anything? The PS pump isn't run by a belt on the Cummins.


Yep, that's true, my mistake on the belt, did not put it together. I did some reading to edumicate myself and found the link below. Could be a bad vacuum pump/seal behind the P.S. pump. I would bet this is your issue. Bad vacuum pump = no brakes.

Click this link here.

Originally Posted By an8sec70cuda
Doesn't the PS pump also serve as the hydroboost pump on these trucks?


Yes.


'71 Duster
'72 Challenger
'17 Ram 1500