Chevrolet Other

Ok it was the caliper on the driver side, the fluid was not going through it was completely dry. We changed that but have absolutely no brakes and the brake light is staying on. Could it be the booster?
I have a 1991 Chevy Astro. The other day the brakes locked up on me and then 30 minuted later unlocked. We have drove it maybe 4 more times since then only a couple of miles at a time. I drove it about 2 miles today and the brakes locked up again. WHAT COULD BE CAUSEING THIS? There seems to me fluid on the master cylinder, but we are not sure if it is that or the booster. Also, inside the van, when you push on the break pedal it makes a noise.
January 13, 2007.

Just to clarify: There is fluid that has leaked outide of either the master cylinder or the booster?

Mastercylinder. It is on some little skinny metal pipes/hoses connected to the cylinder. Also, I forgot to say in the first question that the rubber gasket under the brake fluid lid was swollen come to find out it was swollen over a year ago when we got the van.

Jan 13, 2007.
That's not a good sign. Sounds like the brake fluid has been contaminated. Someone put the wrong fluid in it perhaps. If the cap seal is swollen, all the other rubber parts are probably too. IE. Wheel cylinders, brake hoses, calipers. The inside of the brake hoses may be swollen inside and causing a fluid restriction, wheel cylinder may now be leaking and the fluid is on the shoes.

If you can go after this, pull the rear wheels first and pull the drums and see what it looks like.

Remember you can always post pictures of what you see, so we can better evaluate!