Air coming from brakes..?
Answers:
You have power brakes?? The hiss is the air going in to replace vacumm. This happens every time you step on brake pedal (normal!).This will also happen even when you put brakes on without car moving!
If you leave engine turned off, and operate the brakes several times, it will stop "hissing" as the vacumm will all be gone from system. You will note that the pedal feels very hard and unresponsive now!. Start the engine , and now the pedal feels right and makes the hissing agin!
If this is what you get,- don't worry about it, (as this is normal), and there is nothing wrong with car!!
It's the brake pedal air filter for the brake servo unit, it helps to apply pressure to the brakes, in some cars it is more noticable than others. if you are stopping properly then don't worry.
if its a hissing its probbaly your brake fluid spraying get to a mechainic and FAST!!
its probly rust on the rotors take to shop have them turn the rotors down should solve problem good luck
It might be the brake servo. Not too serious, but would get it checked out. Test to see if it's working properly by: after the car has been running, turn the engine off. Pump brake pedal until it goes hard, once it's hard, push your foot onto brake pedal and switch engine back on. After a few seconds it should then sink down and feel normal. Pump the brake pedal fast and the pedal should go hard and after a few seconds it should feel normal again. If it doesn't feel like this, then it's most likely to be the servo.
Take it a mechanic or back to the person who sold it to you
Lift the bonett and make sure ther isn't a snake inside!
Try :
cavweb-forums.co.uk
vauxhallforum.co.uk
vauxhallownersnetwork.co.uk
I hope this helps.
If the break peddle feels spongy, it indicates that there is air in the brake fluid; it will need flushing with new fluid; also should be checked for leaks.
The hissing could be a leakage in the vacuum servo which powers the breaks, some hissing can be heard normally when the engine is not running and you put you food on the peddle. If you pump the break peddle with the engine off it should become firm after a few pumps, if not there is clearly a leak in the servo (also called master breaking cylinder) and you should get it looked at.
The first thing to do (And most importantly) is check the break fluid level in the engine bay to make sure its not low or empty; this will indicate if there is a fluid leak, if there is DO NOT USE THE CAR.
In any case I would get it to a professional immediately, as with breaks they are the most important thing on your can and its not worth risking any journeys without checking it out. Popping into a Kwik Fit will not cost you money just for a safety check.
First thing is to identify exactly where the hissing is coming from. Get someone to sit in the car with the engine running, the gearbox in neutral, the bonnet up and the handbrake on. The handbrake is cable operated so won't affect this test but will stop the car running away!
The get the person in the car to press and release the brake pedal again and again while you listen and locate the hissing. It is most likely coming from under the bonnet near the back of the engine bay. There is a device there which looks like a vertical flying saucer with pipes coming from the top where there's a plastic fluid reservior. This is the brake servo assist (helps you when you push the brake pedal). This works by the engine sucking the air from the brake servo via a pipe. It could be that the pipe has a leak in it or there is a leak inside the servo unit.
Either way it is a major safety item. Get your car to a garage or someone like Formula 1 autocentres and get someone to check it out. You may be stopping OK but in an emergency.? With kids involved, it's simply not worth the risk.
hydraulic brakes means you have to get leak sealed or something like that
from what it sounds like -absolutely nothing-if your master cylinder (where you add break fluid under the hood)is staying full and your brakes are workin properly-you are just hearing your break booster workin-in alot of cars they are very well insulated and you will not or will barely be able to hear this-but if its older or not insulated alot its a normal noise-kinda makes a lil whoosh sound when you aplly pedal-your booster works off engine vacuum which makes it easy to use your breaks-your just hearing the vacumm assist your master cylinder to put on the breaks-very common-nothing wrong-as long as you have no fluid loss and the brakes are workin its in good shape no worries-if you had air in your break lines you would have brakes-then you wouldnt untill you pumped them up and then they would quit workin again-im sure your in good shape and nervous because you just bought it-but yeah no problems-hope this helps
guess78624 is CORRECT.
You will notice it more when the engine is stopped as the vacuum servo bleeds air every time you press the pedal. This is 100% normal.
If you did it four or five times with the engine OFF, the hissing will stop & the pedal will get VERY stiff an nearly impossible to depress. This is 100% normal.
The vacuum servo 'multiplies' the power from your foot to the 'brake master cylinder' to make braking easier. This vacuum is generated by the normal running of the engine.
Don't worry. It's all OK.
Get it checked mate. Could be lethal !
Get it checked. Even if it's nothing you don't want to put your kids at risk.
Given the fact that you say that this car was sitting on someone's drive for six months before you bought it, my first thought would be that the front brake discs (rotors if American) have rusted and the calipers are seized, so that what you can hear is not so much air escaping, as rust being rubbed off.
It obviously still needs checking, but please use a PROPER mechanic or garage, someone who won't clean the rust off and then tell you they have HAD TO replace the front discs, pads, shock absorbers and tyres just because you appear vulnerable..
The answers post by the user, for information only, UKQnA.com does not guarantee the right.