I guess my luck isn't very good because every time I use a mixture and not straight, in a year or two I have to replace the pump because of bearing failures.
IMHO, you killed the pumps. Harsh words? Perhaps, read on.
The anti-freeze has a lube in it for the pump, and when you used straight anti-freeze the corrosion factor is minimized, as is the thermal transfer. But that's not the correct way to install engine coolant.
When you're using the ol' green anti-freeze and if you're not changing anti-freeze once a year, and chemecially flushing the engine you're doing a disservice to the Jeeep. When you do this, using distilled water is still best, but you keep build up at a minimum. The new anti-freeze also has a new lube and additives that help keep corrosion at a minimum.
Many people find themselves standing by the side of the road every day scratching thier head, waiting for a tow truck, and cussing their vehicle. The real reason they are standing there is that they never read AND followed the owner's manual in the glove compartment.
It's amazing what you find in that doucment.