If you were towing 4000 lbs, and had no rear brakes, you would have some definate issues when tryng to stop. With all four wheels off the ground, even just the rear wheels, have someone apply the brakes and see if the rear still spin. You could have faulty hoses, or calipers, but to the point that neither rear brake works, seems quite rare. There is no longer a valve that controls front to rear proportioning, all done in the ABS modulator valve, and master cylinder. I would seek a second opinion.
Wednesday, February 11th, 2009 AT 11:28 PM