its damn master cylinder his symptoms clearly state this. Soft brakes, pumping to regain pressure, CMON PEOPLE.He is clearly losing hydraulic pressure internally.
If your not sure of the answer dont give him one.

BUY A DAMN MASTER CYLINDER!!

BTW idle drop when pressing the brakes is normal, brake booster uses vacumn.

 

If your pedal goes to the floor, obviously, it's a master cylinder problem.

Duh, that is your biggest problem right now, get the MC and booster at the same time, or the M first.

Honestly, i dont know what it's supposed to do, but out of the 10 cars ive owned, all of them drop the idle when pressing the brake pedal hard.

 

..to the Original Poster..If it Was Vacuum,then the Feel of the Pedal would change.There would be a Difference in Feel with the Car off,and then with the car ON...the Vacuum Hose that goes FROM the booster to the Steel line,has a Check valve..The Hose can only Go On ONE WAY.If it is reversed then the Brakes would Feel Like you "have brakes",but they would Not Really Slow the car down Quick(Like if you Slammed them on,the car would not want to Lock the Brakes up)..NOW.What you are Experiencing,(in my Opinion)is a Faulty Master Cylinder..It Has leaking Seals,,Internally,OR you have a Bad Flex Line(expanding)..BUT,my Gut tells me it IS the Master....If you are Looking for a "cheap Mazda Master cylinder",Try Dave@spooledupracing(here on forum)..he has them,and can ship one out to you...Question????..Did you Just DO the Five Lug Set-up,and Brake Swap??..Did you Bleed the Brakes,properly?.If this is the case You may still have Air in the System..(start at Furthest Brake.and work your way to the Closest to the master..bleeding One at a time)..anyhow..I Hope you Drive safely until you get the Problem fixed..and good luck,Post results.

 

True, we can only offer him advice, it's up to him to take it.

Actually I had those symptoms when my vacuum check hose failed. Good thing I didn't jump the gun and buy an $130 master cylinder when all I needed was a $20 vacuum check hose. The difference is seeing whether pumping the brakes builds pressure or if it doesn't. You can have a perfectly working master cylinder and you'd still have to pump to regain pressure if your vacuum hose fails on you. That being said it shouldn't drop the pedal to the floor, so if that's the case, buy a master cylinder.

To the OP, have you tried bleeding your brakes to simply see if you have air in your lines? I heavily doubt that's the problem, but it's a cheap fix if you have brake fluid.

 

yes i have done the 5 lug / brake conversion and we did bleed the brakes...mayeb there is still air in the system....

Youre all probably right about your opinions, you obviously arent going to give me bad information so my car will be any worse than it already is ... but the truth is I am too broke to afford a master cylinder and all that jazz.

I will see what I can do but at least I dont drive my car much but I do intend to fix all the problems on the car...I just dont plan on starting to diagnose problems or checking for vacuum on the booster or to even inspect anything until I have the parts needed to fix everything.. because in my experience alot of times just fiddling around with stuff you can actually worsen the problem...and last thing i need is to make this any worse than it already is.. i.e (breaking the hose to the brake booster or make the leak double as bad)

Thank you all for your help.

 

Im having this same problem, just started a few days ago. Start pressing the brake pedal and it is nice and firm, as soon as i start applying pressure it will go all the way down to the floor very softly, It still lets me stop, but like the OP said, its not that great stopping power. However, on my left front i did find brake fluid on like the inside of the rim and stuff, however me and a co-worker could find no leaks at all and everything was dry. He thought it might have been the Master cylinder. What do you guys think? Time to order one from mazdatrix?

 

If you pump the pedal and you gradually regain some pressure in the pedal until you use the brake pedal again, it's the vacuum check hose.

If you pump the pedal and no brake pressure is built and the pedal goes all the way to the floor, it's the master cylinder.