Need help determining whether to focus on the Caliper or the Master Cyclinder:

On a 2006 Dodge Durango with Hemi, I replaced the front brake pads and now have a brake pedal which 'fades' or won't pump up and stay. When changing the front brake pads, I pushed the two caliper pistons back into the caliper without opening the bleeder screw, forcing the fluid back to the master. Upon finishing the first side, I tested the brakes by starting the engine and pumping them up and they held just fine. But then upon finishing the second side and starting the engine, I could not keep the brakes pumped up. There doesn't appear to be any fluid leaks, but I think I may have damaged one of the caliper piston seals when pushing them back into the caliper, or I may have damaged the master by not cracking a bleeder when pushing the caliper pistons back and forcing the fluid back up to the master?...

 

Have you try to bleeding the air out of the brake system first? Rule of thumb, always pump the brake pedal first, before starting the engine.

 

The inner pad, upon bolting the caliper assembly back on, had slid off the end of the sliders. I hadn't realized that with the piston compressed, there was enough room for the inner pad to slide that far, and since it was the inner pad it was kind of hard to see, and realize that this had happened. I had done these brakes before but this was the first time this had happened. What a lesson learned.

The brakes are working great now. I really like the ceramic brakes over the metalbestis pads I had before. These are much quieter.