Hi everyone, my name is Lukas!

I have a 2003 Infiniti G35 sedan with a factory 6 speed manual!

Im having an issue with my brake system on my car! With the car off the brakes fall to the floor with no pressure until I pump the brakes. I noticed the previous owner replaced all the brake calipers with ones from a pull a part yard (probably because they had bigger brakes and didn’t want to sell the car with them) so I bled the brakes and still no luck.
I have replaced with the master cylinder and brake booster and bled the brakes again multiple times with a slight increase in pedal feel but still have to pump the brakes to build pressure. What I noticed when my friend was in the car pumping the brakes to help me bleed them is that the fluid goes down in the reservoir when the brakes are being pumped/held down but the reservoir fills back up when the brakes are released and no pressure again. I went and replaced the rear calipers with known good ones and did a full fluid flush and bled the brakes multiple times again with no luck again. I’ve bled the brakes with the car off and with the car running with no change. I’ve checked the lines and saw the fronts were braided steel lines but the rears stock lines but no leaks and all vacuum lines are in good condition. I am so stumped and have no idea what to go do and can’t find anything on this problem besides other people with the same problem. Any input is is appreciated!!

 

The car uses a non-standard bleed order.

right rear - left front - left rear - right front

You MUST follow this order when bleeding the brakes.

I also strongly recommend a Motive bleeder instead of the two-person method.