Intermittent Loss of Brake Pressure and Actual Braking - 1996 900 SE

[Shazam]

Stopped at a stop light, my foot slowly started to sink to the floor. Doing so, the brakes started to work less and less. Once to the floor, brakes didn't even work to hold the car stopped; had to switch to neutral. Pumping the brakes helps temporarily (while still stopped). Then I headed off to home. Come the next light, the brakes were fine, until I was fully stopped for a good 15 or so seconds, and it repeated all over again with the pedal slowly sinking to the floor.

I'm thinking a leak in the vacuum of the brake booster or something. Any ideas on where to start?

[Shazam]

Forgot to mention, no leaking break fluid, reservoir is full.

[Burnsside42]

Booster leaks = very hard rock like pedal.

Master cylinder internal by-pass issue sounds just like the symptoms you have. Ensure your fluid level is not dropping indicating a caliper or line leak - but it sounds like a master cylinder to me.

[nordwulf]

I was thinking master cylinder cup seals but it would be difficult to imagine both would go bad at the same time. If one fails, there should be enough brake power for 2 wheels. Unless one was already failing earlier. I don't know if this is a common issue with Saabs. I remember disassembling a master cylinder at school but that was a loooong time ago.

[Shazam]

Just on availability of parts, it looks like a rebuild isn't feasible. Still no leaks from anywhere that I can see. No one in town has a replacement part either, but they can get it.

Thanks guys.