I have an 86 5000S. Lately right after I start the car and I hit the brake it will go to the floor and start to slow down. If I put it in neutral and race the engine the brake goes back to normal. Brake fluid and hydrolic fluid are full. Need help, thanks Ron

 

If the pedal doesn’t sink to the floor when the engine is not running, check the brake accumulator AKA "brake bomb." These are notorious on the 5000/100/200 models. You might also have a badly worn or broken hydraulic pump that is failing to generate enough pressure and volume to charge the accumulator. You will need to pressure test the system to see which of the two has failed. My bet would be on the “bomb”! Follow the instruction in the Bentley manual on how to perform the test.

 

I will check the pressure on them. Today everything was back to normal, but it is much to scary when you hit that brake and almost nothing happens. Thanks

 

I know that "sinking" feeling. When I got my 1CQ the first week I had one incident where the pedal sunk to the floor. It never repeated again so I didn't do anything about it. If your brake bomb is failing your brake indicator light should flash or come on.

Also check out this site if you haven't already.

http://www.sjmautotechnik.com/