Looks like no harm with the heater pipe hooked to the vacuum tank, but that's real dumb. Get 1 or 2-wire hydraulic hose to replace the heater hose. It won't collapse under vacuum. Try and remove the nut on the check valve. You'll see a simple plunger head down by a spring. The manifold vacuum attached to the nut port and the tank hooks to the fitting that points down. The plunger is rubber that hardens and gets stuck in place by engine vapors and time. Thus valve id pulled against by engine vacuum, entering the booster for use when called for. The reserve is charged at the same time. In the event of a stalled engine you'd have no power brakes at all. When the vacuum from the engine is gone the spring-loaded valve slams shut and the reserve becomes the source of enough vacuum to give you two power brake stops. It works better on the poppet valve boosters as the sleeve-valve units like mine are a large vacuum leak in use. On a sleeve unit you can hear the hissing and the engine flutter and on a poppet there's none of that, but they are more "grabby" with the more-positive poppet valves. The biggest mistake I've seen is people replacing the C-shaped vacuum line inside the booster with fuel or water line, not realizing those hoses are for pressure and collapse under vacuum, negating your power brakes. The original hoses were a cast rubber. I've used single start hydraulic hose that I got to form, somewhat, with repeated baking. An original hose is better.
The two water hoses should have vacuum activated water valves, one for each side. The driver's side comes from the block (or the head) and the other feed from the water pump. When your thermostat, in the driver's side ductwork, is activated by a pull wire from the temperature selector opens the water valves that are supposed to provide equal water pressure to both sides. Each core has an output that T's with the other and returns to be reheated. I, personally, would pay my initial attention to the brakes. The Mark II has great brakes if you start with new drum and new shoes, designed for each other. Putting worn drums on new shoes is a recipe for burned shoes. New and old are different arcs and little initial contact is made, hence the burned material many people think are bad brakes when it was just bad choices.
Barry Wolk
Farmington Hills, MI
C5681126
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Originally Posted by JohnC
