When I press the brake pedal, there's no pressure at all. When the pedal is fully pressed is when the brakes work but not well at all. Any ideas what could be wrong?

 

hmm.
check your bake fluid, and if its full then check for clogs in your fluid resovior.
if tahts not the case.
check for a leaking caliper of overexpanded line.
Ohterwise, I'd sya your master or slave cylinder is shot. or if i'm right the brake assist thing.

 

Check for leaks. Change your brake fluid. But there is a high chance that you just have air in your brake system by letting the reservoir level get too low. Which could be caused by leaking caliper, fittings(unlikely) or leaking master cylinder. Master cylinder failure is a fairly common problem

 

sound like a master cylinder to me. get it fixed asap i got in a wreck because of a bad master cylinder.

 

your brake caliper may be seized. after checking for leaks and bleeding the brakes, if u still have a problem then it may be ur caliper. i had a bad experience with this on a mazda 323 where both front calipers were seaized. no matter how much i bled the brakes, the brakes would not engage until the petal was almost at the floor. there was ZERO brake pedal pressure until thel pedal almost reached the bottom. if u r experincing the same symptoms as i did, this may be ur problem.