Now a new issue with these brakes. Last month I put on NEW calipers and never felt like i got a good bleed. First I started with my Matco Tools suction bleeder - and I think it did more harm than good.

Next I bled 'em the old fashioned way that has worked on this car before. Wife doing pedal presses and I started with the rear inners, then the rear outers, then front.

Never got what I would call a real ~good~ pedal, but the car was certainly drivable. I've been waiting for a decision on whether to get speed bleeders or a pressure bleeder to put on the master. Meanwhile I haven't driven it much at all. Regular stops were OK but on a hard stop, you'd feel the master cylinder bottom out. Fortunately I never had a situation while driving it, that I needed to really jam on the brakes - I only knew about that issue from test drives.

Now as of yesterday, the Booster sounds like it's leaking vacuum when the pedal is depressed more than just enough to stop. It sounds like a good sized vacuum source leak under the dash, unless you are making a very light, easy stop.

Yet, the booster still holds vacuum after the engine is shut down.

So what's next, a booster? How can it hold vacuum after shutdown, if the diaphragm is leaking? It is definitely working - IOW it passes the standard Power Booster test. Engine off & depress the pedal. Start engine, and the pedal sinks a bit. This has been the standard 'booster test' for as long as I've been driving, and this car passes it fine.

So why the noise from it all of a sudden then?

 

Remove the vacuum line from the booster and plug it on the engine side.

Then get in, and drive as best you can in manual mode and see if you hear the vacuum hissing sound you heard before.

If you still hear it then it's a different problem altogether and you're only hearing the problem when the vacuum system is worked by the addition of the booster.

If you don't hear it at all anymore then I suspect the booster is bad and needs to be replaced. Great time to upgrade to a Hydrobooster.

By the way, I love using the check valve speed bleeders. They make bleeding easy for one person and it's a cheap alternative to a Motive.

 

No speed bleeders necessary - just got off the phone - ordered a Motive power bleeder kit.

RE: driving it in the manual mode - hmmm that's a real REAL hard brake pedal. Not sure if I'd wanna try that one.

 

I was thinking up and down the driveway or your street. Something slow and controlled but where you can still operate the brakes in a similar condition to how you drive when you hear the noise. Full manual isn't that bad if you use two feet.