air noise coming from brakes

[bazinga]

well last night i tried bleeding my brakes but some how they turned out worse everytime i put my foot on the brake it makes a kind of air noise and it doesnt really pull the car up.

do you think more air got in the lines or is it something else any ideas would be great.

[Not_An_Abba_Fan]

Sounds like the noise of vacuum in the booster. Is the pedal still high or does it go to the floor?

If it goes to the floor try bleeding them again using this method, but it requires two people:

Have one person in the car operating the brake pedal, and the other at the wheels.

Fill brake fluid reservoir, attach a clear bleed hose to the LHR bleeder, open bleeder and have helper push brake pedal half way down, close bleeder. Repeat until fluid has no air bubbles. Keep checking reservoir so it doesn't empty.
Move to RHR and repeat process.
Move to LHF and repeat.
Move to RHR and repeat.

Test again, if the pedal still goes to the floor, you have either stuffed up the bleeding process or your master cylinder is bypassing and it will need replacing.

If it is hard and high, your booster has a vacuum leak.

[bazinga]

the pedal is still high and when braking i pretty much have to push it all the way to the floor for the car to stop...are the brake boosters a expensive thing to get replaced?and is there any other ways to check that it needs replacing?

[Not_An_Abba_Fan]

Basic test is to pump the brake pedal a couple of times with the engine off to release any vacuum. Then with your foot on the brake pedal, start the car. The pedal should sink a bit. If it doesn't and is still hard, or it does sink and you can hear a hissing noise without changing the pressure you have on the pedal, then the booster or the check valve is stuffed. The valve is the fitting on the booster that the hose connects to. It is a one way valve, take it out and suck on each side, the side that goes into the booster shouldn't let any air through, but you should be able to suck on the side that the hose connects to. If you can suck through both sides, replace it and see how that goes. If you can't suck through the booster side, you may have a leaking diaphragm in the booster.

But what you describe sounds like air in the system and it still requires bleeding.

[bazinga]

Basic test is to pump the brake pedal a couple of times with the engine off to release any vacuum. Then with your foot on the brake pedal, start the car. The pedal should sink a bit. If it doesn't and is still hard, or it does sink and you can hear a hissing noise without changing the pressure you have on the pedal, then the booster or the check valve is stuffed. The valve is the fitting on the booster that the hose connects to. It is a one way valve, take it out and suck on each side, the side that goes into the booster shouldn't let any air through, but you should be able to suck on the side that the hose connects to. If you can suck through both sides, replace it and see how that goes. If you can't suck through the booster side, you may have a leaking diaphragm in the booster.

But what you describe sounds like air in the system and it still requires bleeding.

Thanks for the info that helps heaps i will give that test a go and see what happens cheers.

[Warranty Void]

There's an easy way to bleed brakes but you may go through a fair bit of brake fluid. Connect clear pipe to bleeder valve, make sure it's a tight fit, fill brake fluid reservoir and leave the top off (cover with a cloth to prevent crap getting in) put the end of the clear pipe in a container to catch the brake fluid that comes out, crack the bleeder valve open and leave it for half an hour or until there's no air bubbles left in the pipe near the bleeder valve. Do this for each bleeder valve, making sure that you top up the reservoir each time. This lets gravity do the work if you only have one person. If you have help it's quicker to do it as described earlier, but I find the gravity method pretty much foolproof. Don't let the fluid run out in the reservoir or you will have to start over.