I bought a G35 about 3 months ago and ever since I got it the brakes have been weak. When I hold them in before I start the car they stay firm but then when I start it, the peddle goes all the way down. Ive tried bleeding them and it seems like there is no air in the lines (unless I'm doing it wrong, I bled them in RR, RL, FR, FL, I know the proper way to do it is RR, FL, RL, FR but I found that out after and there still was no air in the lines whatsoever). The brake pads and rotors are brand new and it doesn't feel like they are getting weaker.

I think the car previously had Brembo's but it doesn't anymore.

Any suggestions would be appreciated, Thx.

 

If it’s strong while the car is off, it’s okay. Booster makes it less effort when the car is running 😁.

 

Well the problem is when I'm driving I have to push the brakes to the floor.

 

That almost always means you need to bleed the brakes. Yes you MUST do them in the correct order on these cars. It will take about a full 1 liter bottle to fully bleed out the lines on these cars, make sure you bleed until that fluid looks clean.

The brake booster has nothing to do with how far the pedal travels, it's just how much assist you're getting. If you're pushing the pedal to the floor then it's not building pressure, usually air, sometimes a failing master cylinder which is VERY uncommon on these cars.

 

Ok thats what I was thinking but I wasn't sure if bleeding them slightly differently would affect it that much. Ill try re-bleeding them correctly and see if that fixes the problem.