Ok, so I was driving around in my 93 VX... I do my errands and get in the car to head home. Well, after about 5 miles, my brake pedal pressure is not firm anymore.

When I first tap it, it feels fine... but as my foot applies a steady pressure, the pedal sinks to the floor. I let go of the pedal and re-apply pressure and it's firm at first, but sinks to the floor.

I had to kinda drive with the parking brake for about 10 miles!

Here's what I know when I finally checked it out:
1. I checked the brake fluid level, it's all good. Caps on tight as well.
2. No dripping form the brake lines either, as far as I can see on the ground.

So, what could it be?
-Did the fluid get too hot? (It's only 90 degrees outside... probably ~ 150deg inside the engine bay.)
-Is my master cylinder going bad?
-What should I check for?

Thanks.

 

If your not looseing fluid it's probably your master cylinder.

 

I would have to agree with that. Sounds like the master cylinder is failing.

 

Happened to me. Same exact feeling. Real mushy unless you pumped it a couple of times, but still went to the floor. I replaced the Cylinder and it stopped on a dime after. We bled the brakes (in the right order) like 16 times trying to find out what it was. Didn't look like it was leaking, or bad. But A new one solved it. Not too Expensive either.