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1978 Spider
349 Posts
Discussion Starter #1 (Edited)
I have a couple old ATE boosters I'm wanting to see if they are functional. I have not installed them but they appear to be functional. What I have done so far...

I cleaned up the booster MC O-ring mounting surface with a wire brush to give it a decently smooth finish and installed an old MC I had. I sprayed a little silicone lube on the MC O-ring to help seal it since it looks pretty flattened out.
The vacuum nipple was removed, sealing surface cleaned, the old flat sealing ring replaced with an O-ring.

Both had some residual brake fluid inside the chamber. I assume it to be brake fluid, though not quite as "slippery feeling" as brake fluid normally is. Thoroughly washed and flushed out with dish soap and drained.

With my current booster installed the idle is high and brakes are hard, it's leaking somewhere. Removing the booster hose produces no change in idle. Plugging the booster hose with my thumb produces a smooth idle at 925 rpm. Shutting of the engine the vacuum holds my thumb. So the check valve on the manifold and booster hose pass the "test".

With the engine running and the "test" booster plugged into the booster hose (but not mounted on the car), the idle returns to the same smooth 925. Shutting off the engine and then removing the hose, there is still a good vacuum resisting hose removal.

Both spare boosters seem to be functional. Is there anything else that can be checked or inspected to confirm functionality or identify failure before trying to install one?
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