'98 Ram 1500 3.9L rear brake issues

My cousin has this truck, and today I took off the hub, where i noticed that the wheel cylinder had been leaking, the shoes were covered in fluid. my cousin added to the master cylinder because she complained of no brakes, i cleaned off the shoes and decided they were good for a little while longer. She couldn't replace the cylinder until her check, when i apply the brakes, there is no pressure. There aren't any leaks. The only thing I haven't examined is the lines along the frame. What do you suggest?
Thanks.

The system probably has air in it if you can't pump up any pressure.
If the truck has ABS, the problem is compounded and needs the attention of a brake professional. imo