have someone who knows what they are doing check the rear adjuster and make sure they are working properly. Dodge brakes are notorious for wearing front brakes quickly because they use phenolic (plastic) caliper pistons which have a habit of binding inside the bores. Just as a good practice, always set the emergency brake; that helps to keep the back brakes in adjustment. Worse case scenario, the master cylinder could be bypassing the rear brakes thus putting all the stress on the front, but I doubt that because these vans are notorious for bad wheel cylinders.