My parents and I drive a '96 Saturn SL2 with ABS and 4-wheel Disc Brakes. There is an intermittent problem with excessive brake pedal travel. Most of the time, the brake pedal is fine. It isn't super firm, but it's acceptable. However, sometimes the brake pedal has excessive travel. When this occurs, the brakes will not engage until the pedal is nearly to the floor! The intermittent nature of this problem is what stumps me. I'd say 80% of the time the brakes are working perfectly fine. It's the other 20% of the time that's concerning. Even when the brake pedal does have excessive travel, the brakes work fine-- it's more of annoyance than anything. I've tried two tests to check the condition of the master cylinder. 1. Pump brake pedal several times with the engine off, then push and hold down pedal and check for a drop. It passes this test. 2. Pump brake pedal several times with engine off, then push down brake pedal very slowly to see if it goes to the floor. I tried this, and the pedal goes down lower than in test #1, but the pedal doesn't go completely to the floor. Here's some brake service history that may also be relevant: 1. Flush/bleed brake fluid-- Did this in June 2007 and in Sept 2008. In June 2007, I used a Vacula to vacuum bleed the system. It's possible that I may have introduced air to the system, I don't know. When I flushed the brake fluid again in Sept. 2008, I used a Motive Pressure Bleeder and removed a few air bubbles. After the Sept. 2008 flush, the pedal feel improved significantly and the pedal feel was very acceptable, so I don't think air is the issue. Also, the 1 year old brake fluid that came out was very dark-- almost like coffee colored. The bottom of the used brake fluid container also had some bits of black, gritty rubber seal like material. I wonder if it's from the master cylinder? 2. Replaced rear pads and rotors. My original pads lasted until 90k and they still had ~10k left. However, my second set of pads only last 28k before they wore out. The wear was perfectly even as well...no signs of uneven wear aside from the normal slight difference between the inner and outer pad. So, I was wondering if this is a sign that the proportioning valve in my master cylinder has failed? (The proportioning valve is built into the master cylinder on this car) And as far as I know, all of the caliper slides are working properly. The right rear caliper piston was a bit on the difficult side to retract at the latest brake job, but I think it may have been caused by me using the wrong tool on the "cube." Thanks in advance for your assistance!