How many of us are there? Owners of Dodge based RV's?

Another point to consider is the rubber brake lines. They have been known to get gummy and/or soft on the inside.
As told to me many moons ago, what happens is that when you push on the brake pedal the fluid pushes toward the caliper or cylinder but when the brake pedal is released, the inside of the line collapses thereby keeping the caliper or cylinder in the compressed position .