Losing Braking Pressure, Internal Brake Master Cylinder Leak... I think Options

[Hazmat]

I need some advice on possibly a bad brake master cylinder? I'm onto something here I think!

I have noticed periodically when I apply consistent pressure while braking, the pedal will start to go soft and sink to the floor almost and I have to reapply pressure to avoid rolling forward/backwards. I have had all my brake lines checked for leaks and also had a brake fluid flush done and I'm still noticing it happening every now and then. I have also checked the firewall inside the car for leaks and underneath the hood only to find nothing out of the ordinary.

Now for my stupid question, the braking hydraulic system is it's own system away from the clutch slave & master in our cars correct? There is only a Master Brake Cylinder and nothing else?

Basically how I'm looking at it is

-Clutch Master & Slave Cylinders (It's own system)

-Brake Master Cylinder (No Slave Cylinder)?

I apologize in advance if I sound repeating or if I'm over thinking what I'm really trying to say. Just would like some input please & thank you!

This post has been edited by Hazmat: Nov 4, 2010 - 12:36 AM

[blu94gt]

I just replaced a bad master cylinder on a friend's car that was doing the exact same thing. Seals in the master cylinder were bad so it just didn't hold pressure, but no fluid leaks so it can be misleading. He had been checking all his lines, calipers, etc thinking he was losing fluid somewhere.