The brakes on my 72 chevelle don't seem to be as good as I think they should be. I put a new master and proportioning valve in when I rebuilt the car. I took the booster apart and had it plated. I put a new seal in the back of the booster and the diphram looked good. I put a new check valve in the booster already. I tried driving the car and building up good vacum and turn the car off while rolling. I would think I should get at least one good pump of the pedal after I kill the engine but I don't even get that. Could this be telling me there is a small leak in the booster?

Stick your head under the hood and have someone shut the car off. Should be able to hear a leak to the outside. Might be hard to hear a leak through the check valve and into the manifold, though. Might have to pull the hose off after you shut it down but that's usually a pain to do quickly. smile.gif

Gotta be a way to simply test the check valve too.

Tim.