1999 Chevy Silverado brake job jamb

Ok, you replaced the rotor, pads and caliper on the right rear. Did you replace the pads and rotor on the left side also? Without knowing, do you also have brake shoes on the rear (the emergency brake shoes)? If there is a problem with the hydraulics system for the left rear, all the braking force (for the rear wheels) will be transfered to the right rear. There is a junction block that splits the brake line (located on top of the rear axle) and a line will go to each rear wheel. Ensure you are getting fluid to both rear calipers. (You don't have to do anything with the junction block, just check each rear caliper and make sure you have fluid at each rear caliper).

Make sure the pads are sitting square on the calipers and the calipers are mounted squarely on the axle. Ensure the rotor does not have anything between the rotor and axle flange.

The only other thing I can think of is that the caliper bolts/pins do not have enough lubrication on them. Not enough "sliding action" on the pins will not allow the caliper to float over the rotor and can cause overheating and premature wear. (I had one pin the looked like it was welded inside the caliper due to no lube and would cause my left rear caliper to "Hang-up"....rim would get hot and the truck would shake going down the road due to the binding. Also, pin was so stuck in the caliper, I broke two "T-55" torx bits and twisted a third into a spiral before it broke loose).

thanx Quagmire86
I only replaced the pads , rotor and caliper on the right rear, not the left. would the left side being semi worn and glazed cause the uneven braking pressure and cause the overheating on the right side?

There are parking brake shoes inside the rotor but they looked fine and I dont think they are a problem as they are not used and they dont seem to be in contact with the rotor "drum" when I take the rotor on and off.

I would think the new caliper on the right side would have enough lub and seems to me that it slides well enough but I can take the pins off and relube them to be sure.
It seemed odd the pads on the inside wore out to the metal and the outside ones only wore out about half way
Could it be there is still some air in the caliper and as it heats up it adds pressure to that caliper? just a shot in the dark.
any more suggestions would still be appreciated

Yeah, you should ALWAYS replace brakes (and components) on both sides of the axle when you perform brake work.

Since your Chevy has calipers that only has a piston on one side of the caliper, it is of the "Floating" type. The guide pins need to be lubricated with high temperature brake grease. Make sure the little rubber boots (on the head end of the guide pins) are in good condition (ie No cracks in it to let dirt and moisture in the compartment).