I own an '03 Ford E 350 extended cargo van which I use for work. I carry 2,000lbs 24/7 bringing the total weight of the vehicle to 7,500lbs.
It has a 5.4l gas engine and 40,000miles.

Today I replaced the rear pads, right rear caliper and had the right rear rotor cut(It has rear disk brakes) I figured that the right rear caliper must be hanging up since it was the only one chewing up the rotor(on the inside). Well, after replacing all of this on the right side and moving on to the driver side to change pads there, I find that the inside pad is VERY close to metal. I recently checked the fronts and they are still OK for several thousand. Fronts were not replaced yet.

I am used to having the fronts wear out over the rear on a 2 to 1 ratio. On this van it seems bass akwards, so my question is : Is this wear normal for carrying this kind of weight or do I have 2 calipers that are bad(or a bad brake valve)? Did I waste time and money replacing the right caliper or am I only half done? All of my driving is local.
Thanks for the replies.