Ah, so..

I posted about my wreck a few weeks ago, etc. Well, we thought that my brake booster had busted..so, we replaced it. We got everything back together, filled the reservoir up with brake fluid, everything, and went to pump the brakes..no pressure whatsoever. So, then we cranked it and all and whenever we took off the vac line to the brake booster and plugged it with our finger it regained pressure..until we put it back on the brake booster. Any ideas? I need some help, bad.

Did you bleed the brakes? Is there a busted line?

If you replaced the master cylinder, did you bench bleed it?

Replaced master cylinder as well. Checked all lines, they're fine. Bled everything too. This may sound dumb, but I'm only 16 so bare with me..what's bench bleeding?

Purging all the air out on the bench. Stick a screw driver in the cylinder on the plunger and force it in with your finger over the hole for the brake line, allowing the fluid and air in the cylinder to purge out. Repeat until only fluid comes out. . If you have done this, you need to check for a busted line or change the rubber seals in the cylinder.

1. Put master cylinder into a vise, making sure it's level. A few degrees off won't hurt anything, but it should be close.

2. Fill resivoir with brake fluid.

3. Cover the holes that exit the fluid (where the brake lines srew into) with your fingers. (this may be combined with step 2)

3. Using a wooden dowel or other non-metal object such as a window shade rod, press the piston into the cylinder all the way. This will push air and fluid out from under your fingers. It takes some force to press the piston in.

4. Slowly let the piston out while keeping your fingers on the holes to not let air back into the cylinder.

5. Repeat this step until air stops pushing out and only fluid comes out. (about 3 minutes)

6. Quickly re-install little plastic caps that the new master cylinder came with to hold in the fluid. (you do still have them, right?)

7. Install master cylinder onto vehicle! Bleed brakes like normal, and take it from there!