This is long.
1st: I am not a professional mechanic. I have been doing brakes since I was about 15 years old. I am 40 now and I have not hurt me or mine (yet) working on my brakes. The golden rule is if it leak don't drive it. If you are not mechanically inclined check around and take it somewhere good. Or fine someone good to teach you. I have learned a lot from my dad. There is always the local high school evening course.
You would help us help you my telling us a little more about your truck. Like what year and model (i. e. 2500/3500). How many miles it has on it.
Start with the simple things first. This will take you at least a Saturday morning (and no beer!). We want you around to tell about it afterward.
I have heard from Glenn at EGR (he sells after market brake for RAMs) that our calibre's generally last ~60K miles. I have about 65K miles on mine and the pins are getting worn. I have already had one serious pull. I buffed the pin and coated it with anti-sieze. It seem to work for now. I prefer anti-sieze over grease because it does not separate like grease. It does not tend to run and get into the brakes like grease does and it can withstand high heat. They use it on exhaust bolts.
What we know: You have either a calibre hanging up or the piston in the calibre is hanging up. The weak link in our calibre's is that they are single sided (e. g. the piston is only on 1 side) and they slide on 2 chrome pins. If the pins go dry they will hang up. So, the cheap and simple thing is to remove the wheel and pull 1 pin at a time and inspect. If it is gouged you can try to fix it with the suggestions of one of the previous posts or go down to Dodge and get new ones. In either case you are on borrowed time. If the pins look fine put some anti-sieze on them and reinstall. The next thing would probably be the piston hanging. Inspect the rubber brake line first just to make sure that it is OK. If the piston is hanging it is either rebuild or new calibre time. Don't go cheap and replace just one side unless you really like working on it more than driving it.
The other thing that you should check is the rear adjustment. Jack the rear end and remember to put jack stands under it. Pull the tires off and then pull the drums. Take a look at the shoes. They should be even thickness across the length of the shoe. I had a problem at ~30K miles because I did not use the self adjusters enough. I back into a up hill driveway and was not doing enough backing and stopping. What this did was cause the shoes to become out of adjustment and wear on only one end. You get less braking power and the shoes wear very quickly. About the same time I had the front rotors warp. While you have the rear drums off, look at the components. Make sure everything looks dry. If it looks the slightest bit wet you have other problems (e. g. a leak). Remember, if it leaks don't drive it. Also, if you think you have a leak remember to top of the master cylinder.
If the front pad have dragged for a long time it may have glazed the pad and/or the rotors. Also the rotors may be warped. Removing glaze is pretty easy. 400 grit wet/dry sand paper and a flat surface like a good block if wood. You will probably have to pull the calibre and tie it up to the spring. DO NOT let it hang by the hose! Spin the rotor and sand. What you want to do is remove just the glaze. You can watch it go from shinny to dull and you have probably have done it. You will then need to pull the pads and scuff them too.
If you have a dial gauge you can find out of the rotor is warped. If not take it to a good brake or wheel and tire shop. If it is warped you will have to have them turned. Make sure that they are turned on the truck. The best you can get off the truck is . 004"-. 005" which is within spec but SUCKS! Mine were giving me problems at . 005" with a steering wobble. After turning on the truck they were within . 0005". No wobble since.
After you get through all that, think about bleeding the brakes. If you glazed/warped, there was a lot of heat. Even if you did not, Dodge is supposed to bleed at the 30K interval service or every two years. Most do not. Why? Because they will have you back earlier if they do not. It is in their best interest if they don't because they will get you for a complete brake job which will cost a lot more $'s. Brake fluid pull in water from the air. The more water the lower the boiling point. The difference in boiling point between old ~250F to new fluid ~500F. I was in a old truck with a heavy trailer which boiled coming down a grade. It was no fun. It is a good way to wet you pants or worse.
After doing all the inspections, clean everything with brake clean. Remember those brake will not work well if you got your greasey hands on the pads/rotors/linings. If you use liberally you can go through 1/2 to a can for all 4 corners.
Put everything back together and inspect. The final test: System pressure test.
Pump the pedal 6-8 times and then press down as hard as you can and hold. If it holds you are golden. If it continues to go down you have a leak. Find the leak and fix it.
After the system pressure test it is still a god idea to inspect everything again. You have cleaned everthing off with cleaner so it should be easy to spot anything wet. If it is wet you have a leak. Find it and fix it.
Any one else out there think of anything that I forgot. It is getting kind of late here.