Hi All, With the reservoir cap off, when I reach through the drivers' door and slowly press the pedal with a broomstick, fluid flows back up and out of the small feed port on the floor of the front chamber (rear brake circuit). Normal or not?
If you are just checking the fluid levels,that is normal.If you see air bubbles,it means there is air in the master cylinder and/or lines.If not low in the reservoir and your peddle doesn't go soft or feel spongie when pressure is applied (with master cylinder lid/cap on),you should be alright. It's always a good idea to bleed the brakes or have it done if it hasn't been since you've owned the car.Then you'll know the last time it was done,and have confidence that air is not in the system.
That's because there are very small compensation ports into the piston bore. It relieves the pressure when you release the brake pedal. The piston assembly moves slightly forward and it closes off this port to apply the brakes. You should see the fluid move, but only for an inch or so of the pedal travel. If it continues as you press the pedal, the cylinder is leaking internally past the piston seals.
That's reassuring, it only does it for the first bit of pedal travel. Come to think of it, we were flushing the "mud" from my son's brakes last month and while he was stabbing the pedal (with the cap off) it was puking fluid all over the engine compartment from the rear circuit. Guess the harder you press, the more violent the discharge...
Compensating ports. Thats why you never hit the pedal with a cap off. Some get real good distance....messy. So yes its normal.
