I get a hissing sound by my brake peddle when I apply my brakes and it does not go away. When I run the engine and depress the brake peddle and hold it there and turn the engine off the brake peddle comes back UP. The hissing is contant when the peddle is pressed down, The RPM goes UP when brakes are applied.

Shelly, in most cases, these can be cured by replacing your brake pads/shoes. However, you stated that you are hearing a "pump" sound when you depress the brake peddle. So this is telling me that you may have either a vacuum issue, or having an issue with your "Brake Booster". That also runs off a vacuum. A little info for you. ^^ When your engine is running, the entire system is put under a negative vacuum. This controls things like cruise control, and vacuum assisted brakes. Older vehicle did NOT have a vacuum assist, and were called "Manuel Brake" systems. While these were more reliable, the were harder to push the peddle until the brakes worked. As an example, with your car turned off, depress your brake peddle about 3 times and then try to press it as if you were stopping. You will find that the peddle is much harder to press than if the engine were running under the vacuum. The reason I asked that you depress the peddle 3 times, is when the engine is off, you are no longer building pressure, so this pressure is naturally bled off when you use the brakes. If this does not happen, and your brakes are always hard to depress, then for sure your having a problem with your brake booster. I hope this helps, and good luck. ^^

You need to have the brakes inspected. This noise is the brake pad wear warning tab hitting the brake rotor.;

This sounds like a bad brake booster, that sounds like the hissing is when brake is applied. check the booster . thats why the engine sutters when brakes are applied, the booster starts to leak vacuum, thats where iwould start. good day

Brake booster diaphragm is gone resulting in vacuum leak and hence soft brake and hissing sound. Get the brake booster changed, it will be fine.

It is a defective brake booster. When the internal diaphram of the brake booster develops cracks or pinholes from age, the crankcase vacume pulls air through the defective break booster diaphram from the air intake valve located on the rod connected to the brake peddle. At first the air leak sound my change or even go away when the brake peddle is depressed. But over time the booster diaphram will detierorieate to the point where the air leak sound will be contiuious. This is a problem that should be addressed ASAP as a defective break booster reduces the power assist to the break peddle and may make it difficult to apply enough break pressure to stop in an emergency situation.
Have the brakes checked by a certfied brake shop right away.

Yes sound like brake booster. most of time when booster is going bad makes hissing sound when brake applied.But should not make any kind of air leakage noise at all.Replace brake booster.Hope this was helpful for you.

The power brake booster has a bad valve. I can't suggest where to find a new valve for it, but you can buy a rebuilt replacement. They are usually not hard to put on.

Hello;
Yoou most likely have a vacuum leak in the line from the booster to the intake. It could be a bad booster or check valve as well.
Thanks;
Rich
RPM Northwest

air may have gotten into your brake lines. try bleeding your brakes. this will require two people

Your Brake Master Cylinder is Going Bad. Have this Replaced and that Noise will go away. Please Rate my Response, I need all the Help that I can get! Thanks!