Odd 4x4 brake problem

I've got a 1998 ram 2500 4x4 that has a brake problem I would like help diagnosing:
Often after I drive on rough surfaces (washboard, big bumps, potholes, etc), my brake pedal will then have an "odd" feel (less freeplay but not firm) and the truck will pull hard left upon braking. Stopping distance is increased.
It seems like the right caliper has been pushed away from the rotor.
If I stop the truck & step HARD on the pedal, the pedal will move much further than normal (I can feel something actually "give") & the braking action will return to normal until the next rough-terrain situation.
Any ideas?

It kind of sounds like the calipers or caliper adapters where they slide are dirty, worn or grooved. Those years used Delco brakes and seemed to wear more than the later Bosch setups. Could be pads coming apart, or rust behind the pad silencer shims, or a caliper getting ready to stick. Are the wheel bearings tight? Back sides of rotors smooth, factory stuff liked to get holes in them.

Jack it up and make sure the wheel bearings are tight. If loose it may be pushing the calipers piston back. Thats why it pulls and seems to change when pumped.

Wheel bearings seem to be the most logical cause but they are sealed hub & seem tight ( can't detect any movement when I jack it up & pry). The slides & guide pins are clean, smooth & lubed.
Where would the possible holes you referred to be located?

Backside of the rotors where the pads ride.

Thanks for the clarification. Rotors are smooth. Pads are thick. So far, signs point to sealed hub replacement.

I have a very similar, if not the exact same situation happening with my 2001 ram 4X4, but it's a 1500 series (also occasionally pulls to the left). I mostly feel while towing the boat (no trailer brakes), and needing to stop slightly quicker than normal. My calipers and pads were replaced about a year ago. My next step is/was going to be to change the rubber lines, which I should probably do anyway.

Yep wheel bearings. Doesn't take much slop in a hub to allow the rotor to wobble and cause a caliper to back off and give an extra .010 between the brake pads and the rotor. That .010 could give you brake delay, a slight pull, and funky brake pedal feel caused by that one front wheel.

Picture it this way: both brakes get the same amount of brake fluid at the same time when you step on the brake pedal. Once the pads are seated against the rotors, the pedal movement builds pressure until it all stops. If one of the brakes has more clearance between the brake pad and the rotor, the brake with less pad clearance applies the brakes first, but the other brake with more clearance lingers before applying the same pressure (if it applies the same pressure at all). The pedal feels funky because one brake functions correctly and the other doesn't. The brakes pull because one brake functions and the other doesn't. The more the difference in clearance between the brake pad and the rotor on the two sides becomes, the worse the brake problem becomes. Gene

I wouldn't have thought of bearings being the culprit. TYVM!!! Something else to put on my list (at 170,000 miles).

EDIT: Hey Gene, do you have a recommendation for which brand hub to use (or not use)?

Sorry, not up on which of the over priced hubs are still actually good anymore. Its been 3-4 years since I've bought a bearing hub, I suspect a lot has changed since then.