Brake Booster Failure? Removal Instructions/Second Opinion Needed Options

[chris14020]

Well, I'm in the crossroads of a huge project. I just tore down my Celica, and completely 'restored' the engine bay -- rebuilt the engine down to the crankshaft, rebuilt the transmission, cleaned everything up and out real nice. I have everything 'pretty much' together, the last issue is I can't keep brake pressure. If I pump em a few times, they get hard, but it feels like the brakes are not bled right and they soften up again. I gravity bled half a huge bottle of brake fluid through them, and bled them the traditional way on top of that. When I press the brakes, if I press them hard I can hear a 'hiss/whoosh' in the air intake. Does that mean the booster diaphragm/piston o-rings have gone bad? And if so, does anyone have removal instructions? I reaaaaally do not want to have to tear more apart than I have to. Thanks!

One last question: Does the clutch have any sort of 'booster' or is it the same? If I take the clutch and stomp it to the floor as far as I can (reasonably, not putting it straight through the metal or anything) I can hear a bit of a 'hiss' too, is why I ask. Before I did all of this my clutch was 'failing' (it was pretty well worn), but I'm almost wondering if maybe it was that and not the clutch just yet.

This is a picture of the car, if you want to see. It's a 1996 Toyota Celica ST 5-speed. I know it's not 'worth' what I'm doing to it, especially without an engine swap, but there's no rust, and I have sentimental attachment to the car. I have cleaned everything up, undercoated/rustproofed around the bay and undercarriage, replaced almost all suspension parts, replaced the front core support (drilled out all old tack welds, swapped new in), put in a whole new back quarter panel, and so on. It will be painted soon, just gotta get the mechanical issues out of the way. This was my first engine rebuild and 2nd transmission job, and aside from the milling/machining (I had the compression upped to 10:1 and hot tanked, and the valve seats vacuum tested) I did all the work myself. Not 'worth it' value-wise, but in knowledge it was to me.

http://imgur.com/a/96T9S

[Bitter]

Sounds more like a bad master cylinder than a bad brake booster, booster will typically cause a high/hard pedal like trying to stop the car without the engine running.

[chris14020]

Anyone else have opinions? I can absolutely try that, I have a spare master cylinder. But just curious if the 'noise through the intake' is normal.

[chris14020]

So I said **** it and pulled the brake booster out of my second Celica to test. The brakes now work fine. If anyone stumbles across this in the future, it was the brake booster, for me.