1984 ford 700 brake system ( after the fire)

Got a junk 700 ford off road farm dump truck. The parking brake blew a line on the manifold and the flames ruined all the lines coming out of the pump. Two are return lines and one is pressure of which I will have one made. Can I disable the parking brakes temporarily and is the pump that runs dextron a power brake pump or just control the parking brake. Need to haul 3 or 4 more loads

Toby

We need more information! Gas or diesel engine? Air brakes or hydraulic brakes with standard hydro-vac power booster? L 700 or F 700 model? Armand

Sounds like you have Lucas gurling brakes. These have a hydraulic parking brake. You can manually release the parking brake. You have to turn the bolt that sticks out of the park brake actuators on the rear wheels. I don't remember which way you turn it but I think it tells you on the actuator.

Gas
Hydraulic
did not see vacuum booster
has a hydraulic parking brake

I think a f700

I ordered all of my school buses with Lucas Girling brakes. I liked them. They can be a bear to repair if someone has messed with it or there's been a fire. They are also expensive if they haven't been maintained. Keep fluid in the belt driven pump. It's an expensive sucker to replace. I still remember the sting of the last one.

The truck has multiple brake systems. It is hydraulically assisted hydraulic. The pump on the left side of the engine supplies power to the hydraulic assist when the engine is running. If you step on the brakes with the engine off or it stalls, a 12 volt motor under the master cylinder kicks in and supplies the pressure the pump usually does. Those boost the regular brakes (like vacuum does on a car). They also supply pressure to the dash switch to set the parking brake. They are a lot like air brakes in that having the park brake set means there is no pressure in the system. When you release it (pull the lever down) it pumps the system full of that ATF to unlock the rear brakes.

You can "cage the brakes" by turning the bolt on the end of the chamber at each rear wheel behind the axle. Be very careful. What you are doing is compressing a large spring that has enough energy to kill you and a small elephant.

If you cage them you can move it but you won't have power brakes without that system in place. That motor will also kick in as it will sense a low pressure situation. It isn't just a wiper motor (even though it looks like it). That thing will drain batteries fast. It will run nonstop. Off road or not, you are going to have to get that system up and running.

Actually the regular brakes and the parking brake systems have completely separate hydraulic systems. They do use the same drums and shoes. Caging the park brakes will not have any affect on the regular brakes. The parking brakes are applied by spring pressure by forcing a wedge between the pistons of one of the brake cylinders. Pushing in the park brake control on the dash allows pressure to build in the park brake release hydraulic system to compress the springs and pull the wedges out from between the brake cylinder pistons. That in turn releases the parking brake feature.

So much for Ford's better ideas ! LOL. What these other fellows have described has got to be one goofy system. I am glad I have not seen one.
My uncle once said EVERY vehicle should have air brakes. You can still have a leak and still have brakes and they are usually pretty simple and trouble free.