i have a 2004.5 dodge ram 2500 6 speed and i am having brake issues. the problem i am having is the brake pedal is tight no free play at all as soon as you touch the pedal the rear brakes will grab if you are not careful. i took it to the dealership to have hydroboost tested and pressure but they told me they did not have the equipment to test it so he fooled with it for an hour and told me he thought it was the master cylinder so i replaced it and did not make any difference so i bought a used hydrobooster and it was better but then started doing the same as the original so they gave me another and with it the pedal was hard along with doing the same thing so i bought a rebuilt one and could not get the whine out of it along with the brake pedal pulsing when you turned the steering wheel so i took it off and returned it. when pulling a trailer it makes it fun because the truck brakes are doing all the work. when i installed the new master cylinder it would not sit flush with the booster like the rod was too long. not sure what to do now.

 

No real idea what your problem is and I admit to not being an expert, but from your description I am wondering if the problem could be in the flex hoses. Have read reports on how the teflon liner pulls free and partially blocks the flow. Could it be that a liner has come loose and not allowing the pressure to fully release? In other words, the hose allows flow in one direction, but not the reverse.

Let us know how the problem is resolved.

 

My son had the same problem on his truck. Although it was an F150 Ford the problems sound similar. He found the rubber hose on the brake line near the wheel was pinched by the rust on a clamp where the hose passes through. It allowed fluid to be pushed through but then would not allow it to relax thus the brake stayed engaged. He removed the brake hose and found this clamp had really rusted enough to squeeze the hose almost flat. After taking a large screwdriver and forcing the clamp open enough to remove the rubber hose he could easily see why brake fluid could not pass easily in both directions. He replaced the hose assembly and brakes were perfect again.

 

i have replaced all rubber lines on the rear and if you crack any bleeder or line there is no build up of pressure. has me stumped