I have a friend with a 1976 C65 Chevrolet dump truck. He bought a 1989 C65 chassis to update his truck. He used the cab and also the front axle. The front axle from the newer truck had disc brakes on it so he thought he was making an improvement to his truck using it. He installed the master cylinder from the '76 truck and used the same hydrovac from the truck. The Bendix # for the hydrovac is #2513812. Now he has a high pedal effort and marginal brakes. I'm looking for some help to get the correct hydrovac and master cylinder for the front disc brakes / rear drum brakes that he has on the truck now. The '89 parts truck he bought originally had a 8.2 diesel in it. The master cylinder and hydrovac off that truck are long gone.
Thanks, Don