Hey guys

im having a problem with my brakes when the engine is off i have good brake pressure as soon as start the engine the brake pressure is non existing replaced the master brake cylinder and that did not help bled the brakes and nothing checked the lines and no leaks new brake callipers in front .

Please help and what can i do other than putting a big brake kit on to help strenghten the brake pressure

thanks guys.

Civic monster

 

Please use periods... Might make it easier to answer ur question.

Are you saying there is no brake pressure when the engine is off? As in when the engine is off, the pedal goes to the floor?

 

Sorry for that
when the engine is off i have brake pressure,but as soon as i start the car i loose all pressure.

 

Sounds like a brake booster problem. Either there's an issue with the vacuum lines or the booster itself failed. Check the hoses leading to the booster and manifold for leaks.

 

First try bleeding the hydraulic system. If that doesn't help, the master cylinder may be bad.

 

He said he already replaced the master cylinder and bled the system with no change. Leads me to believe it's the booster.

 

I missed the fact that the master cylinder was replaced already, but a bad brake booster simply does not fit. This would make the brake pedal harder with the engine running (no brake assist) not softer.

This problem is usually caused when the hydraulic system was not bled properly, so I should have said rebleed the system and do it in the correct wheel sequence.