The front brakes on ALL prevo are standard non maxi single diaphragm brake chamber. Under normal braking they may see 10 or 15 pounds of air pressure, minimal. If it should leak it will only leak when you are using the brakes.
I have never looked here and had no idea if these were original or not so I opened them up. Good thing I did.
Everything is pretty crusty on the surface but very clean on the inside and will easily provide many more years of service with simply a new pancake and rubber brake line.
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You have to check the return spring behind the plunger to make sure it is not overly corroded. This one was fine.
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This is not new but the inside of the original chamber.
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