I would try bleeding the brake lines first to make sure there is no air in the lines. Could be the brake booster (if applicable) or even the master cylinder. If your car has a brake booster maybe check the vacuum line on it first.
Your car could be losing brake pressure because you have a bad ABS control module. It also could be a bad brake booster.
That would be normal for a vehicle with power brakes.
Some vehicles` oil pressure will do this when at an idle. This is normal, if the oil pressure does not get higher when at higher rpms then something may be wrong.
Shouldn't have any effect, either positive or negative. The brake pedal may sink a little once the engine has started running, but that would be normal as vacuum pressure increased.
First the driver puts pressure in the foot brake, which then pushes a small piston, the piston then exerts pressure in the brake fluid. Then the increased pressure is transmitted through the fluid in the brake lines to a larger piston within the wheels of the car. Each piston pushes in a brake pad which the rubs against the brake disc, and the wheels motion is slowed down by the force of friction.
You could have a leak in your power brake system.
Your car's brake system may not be building pressure due to air in the brake lines, a leak in the system, or a problem with the brake master cylinder. It is important to have a professional mechanic inspect and repair the issue to ensure your safety while driving.
about 12 psi
Braking distance is a function of pressure applied to the brake pedal.
A car has to have brake fluid to allow for the effective operation of the brakes to stop the car. When we apply pressure to the brake pedal, brake fluid, which is largely incompressible, will transfer that pressure to the pistons that operate the in the calipers or the pistons that operate the brake shoes. Further, the fluid must be of the correct type for the system in which it is used. The continued safe operation of the brakes may be compromised by the wrong fluid.
You should have someone look at your master cylinder,sounds like the diaphragm has a hole in it.
It seems like there might be air in your brake system. You should try bleeding your brakes and filling it with fresh brake fluid.