[Kenn]

Has anyone converted the air brake system for a three axle "tractor" to a three or two axle "truck"? My Peterbilt has a warning sticker in the door jam that says (This vehicle is a tractor. It has a federal motor vehicle safety standard 121 air brake system arranged for a tractor operation only. If this vehicle is rebuilt into a truck or used as a truck the air brake system must be revised to permit it safe operation as a truck. Contact your Peterbilt dealer for instructions.) I called Peterbilt and was told that I need to have the bobtail proportioning valve removed and install a R 14 relay valve. My truck was a three axle and has been changed to a two axle. The spring brakes were moved to the rear axle and I have an R 8 relay valve that controls both the rear service brakes and spring brakes. I would like to do the work myself but I can't find the bobtail valve. Any help will help. Thanks Kenn