I never thought installing a brake booster, master cylinder and all four brake calipers could disable a truck for three days. So I installed everything and just shortly afterwards the ABS light and Brake light come on brakes start dragging. I bleed the brakes so much I ruined the bleeder seats. Pulling my hair out I just didnt get it. This morning I go and talk to a master Dodge mechanic and he knew exactly what was up. He had me put two 3/8 nuts between the master cylinder and the brake booster and go drive it. Sure nuff 300 yards down the road the brake light goes off the ABS light went off brakes stop dragging and everything is back to normal.
The company I bought the master cylinder from used a different style plunger than Dodge and didnt include the new rod. The rod from the booster to the plunger is about 3/8 of a inch shorter than stock. So the whole time the master cylinder had pressure on it. 

Good to know.  Thanks for sharing.

Sound more like the wrong part has been sold. A lot of parts are sold for different applications for totally different makes and models. 

What this guy thought was the depth of the plunger is not as deep as the stock one. Kinda like you say, Im sure the same plunger works in a bunch of other units. I went to the parts store I usually go to and he told me he would have one in but I couldnt wait so I got that one from napa. I went back and told him what I found and he pulled the one he just got in and it had a rod already installed. The wild part was he also had the paperwork stating a shorter rod maybe needed but no extra rod in the box. Anyway I got the new shorter rod put in today and its all good to go.

Just remember that when you get a new master cylinder if you get the proper one that OEM used it will be too short again. So you might have a low pedal next time. 

Saved the old rod, its now in my million parts bin somewhere. 

I've got boxes of stuff either from Beast or Thor I've got piled up on the top shelf. My problem is eventually I find someone that needs that part and it goes bye-bye out the door in someone else's truck.