Question about Nissan Altima

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Check valve vacuum booster

Where is the check valve

Posted by Anonymous on

6 Suggested Answers

6ya6ya
  • 2 Answers

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Posted on Jan 02, 2017

kapishtech
  • 2272 Answers

SOURCE: brake pedal is hard but brakes not very effective

Check the brake fluid first.is it low or no brake fluid at all.is the brake fluid got dried up or leaked out. Sounds like the power brake booster is bad, that is what the master cylinder is bolted too. There is a rubber hose that has a plastic valve in it were it snaps into the booster, Pull that rubber hose out of the booster and off of the engine, Now the end that you took off the engine. You should be able to **** through the line, but not be able to blow through it. If you can then replace the valve, It is a one way valve.
If that is all right then hook hose back up to the engine and start engine, You should hear a major vacuum leak at the valve end, put you finger over the valve and it should stop making noise and engine should smooth out. If it don't the rubber hose must be leaking or the tube on the engine were the hose hooks to is stoped up.
Also check the master cylinder if power booster is replaced. If the brake light is coming and going check the brake light switch. check fig for the internal assembly parts:-- bdea807.gif

To check engine vacuum, connect a vacuum gauge to the supply hose that runs from the intake manifold to the booster. A low reading (below 16 inches) may indicate a hose leak or obstruction, a blockage in the exhaust system (plugged catalytic converter, crushed pipe, bad muffler, etc.), or a problem in the engine itself (manifold vacuum leak, bad valve, head gasket, etc.).
The condition of the diaphragm inside the booster is also important. If cracked, ruptured or leaking, it won't hold vacuum and can't provide much power assist. Leaks in the master cylinder can allow brake fluid to be siphoned into the booster, accelerating the demise of the diaphragm. So if there's brake fluid inside the vacuum hose, it's a good indication the master cylinder is leaking and needs to be rebuilt or replaced. Wetness around the back of the master cylinder would be another clue to this kind of problem.
To check the vacuum booster, pump the brake pedal with the engine off until you've bled off all the vacuum from the unit. Then hold the pedal down and start the engine. You should feel the pedal depress slightly as engine vacuum enters the booster and pulls on the diaphragm. No change? Then check the vacuum hose connection and engine vacuum. If okay, the problem is in the booster and the booster needs to be replaced.
Vacuum boosters also have an external one-way check valve at the hose inlet that closes when the engine is either shut off or stalls. This traps vacuum inside the booster so it can still provide one or two power assisted stops until the engine is restarted. The valve also helps maintain vacuum when intake vacuum is low (when the engine is under load or is running at wide open throttle). You can check the valve by removing it and trying to blow through it from both sides. It should pass air from the rear but not from the front.
Replacing a vacuum booster is a fairly straight forward job. All you have to do is disconnect it from the brake pedal on the inside and unbolt the master cylinder. The pushrod that runs from the booster into the back of the master cylinder must have the specified amount of play.
You will typically find the power brake booster mounted on the firewall attached to the master cylinder. The master cylinder is connected to the brake pedal.
Thanks. keep updated for any more query.you can rate this solution and show your appreciation.

Posted on Jul 15, 2010

c1apton15
  • 3400 Answers

SOURCE: When car is idling with AC on and power brakes

Check another vac source in/around engine. When you load engine with brake booster, then lower vac pressure w/Up idle, it's amplifying another vac source that might be weak.

Posted on Mar 10, 2011

alicantecoli
  • 22156 Answers

SOURCE: 2004 freestar booster is loosing vacuum overnight.

without lookng noboby can tell you ,ask a local mechanic to have a look

Posted on Jun 27, 2011

suarezelec20
  • 259 Answers

SOURCE: Why would I have plenty of vacuum at my brake booster line? But none in the smaller lines on my 1977 Mercedes 300D like the one going to my shut off valve. Rebuilt vacuum pump and the engine only has

You still have a leak somewhere or it is plugged up. The brake booster is not the culprit. Find the vacuum canister and trace from there checking each line.

Posted on Sep 10, 2012

Testimonial: "Ok thanks this has been a long drawn out battle."

skychief2001
  • 21873 Answers

SOURCE: find a 3 way vacuum connetion booster brake check valve

If you can't find a new valve, you can buy a tee fitting and cut the hose a few inches from the valve. Then add the Tee fitting to get the third connection.

Posted on Apr 07, 2013

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2 Answers

Hard brake pedal


You can only have whatever the engine vacuum is
at any time.
Is there vacuum to the booster check valve
& is the valve working,assuming you have the
old one or a new one with the new booster.
Does fluid flow out all 4 corners?
Are the Rubber Flex Hoses Collaped
Calipers Rusted & frozen?
Did you remove the master & clean out
the moisture from around the piston
That is where you start,then flush & on to
every component in the system, if they are
on the vehicle for many years
You do realize brake fluid gets changed every
2 years on all vehicles or you got big problems with
moisture in years to come

Jul 18, 2013 | Cars & Trucks

1 Answer

Vw golf 2000 the brake pedal is to soft when you apply it and seems like is not going to stop but it does, what is the problem?


Not sure if you have done all this.



BRAKE BOOSTER INSPECTION

Functional test:
1. With the engine stopped, Depress the brake pedal several times, then depress the pedal hard and hold that pressure for 15 seconds. If the pedal sinks, the master cylinder, brake line or a brake caliper is faulty
2. Start the engine with the pedal depressed. If the pedal sinks slightly, the vacuum booster is working. If the pedal height does not vary, the booster or the check valve is faulty

Leak Test:
1. Depress the brake pedal with the engine running then stop the engine. If the pedal height does not vary while depressed for 30 seconds, the vacuum booster is OK. If the pedal rises, the booster is faulty
2. With the engine stopped, depress the brake pedal several times using normal pressure. When the pedal is first depressed, it should be low. On consecutive applications, the pedal height should gradually rise. If the pedal position does not vary, check the booster check valve.

Check valve test:
1. Disconnect the brake booster vacuum hose at the booster.
2. Start the engine and let it idle. There should be a vacuum available. If no vacuum is available, the check valve is not working correctly. Replace the check valve and retest.

END TEST

Nov 06, 2012 | Volkswagen Cars & Trucks

3 Answers

Brake pedal got hard now it takes everything you have to stop it from moving


skdavisbob, This sounds like you have a problem with the brake booster that is attached to the firewall. When these boosters fail it is like trying to stop a house as you describe here. There is a one way check valve near the top of the booster that uses vacuum from the engine to operate. Inspect the hose and be sure that it is attached at both ends and that there are no leaks in this hose. This can be done by running the engine and listening for a leak. (hissing noise) Replace the hose if faulty. If you don't hear any vacuum leak then turn the engine off and pull the check valve out of the booster. This takes a little effort as it is quite secure in the grommet. You should hear a vacuum leak for a split second because when the valve is removed it will allow air in (if it is working properly) and you should hear the leak. If you don't hear the hiss, then test the valve by blowing through it both ways. As stated, this is a one way valve and you should be able to blow air through one way but not the other. If you can blow air both ways then the check valve is faulty. If the hose and valve are working properly then you will have to have the booster replaced. Good luck with this.

Aug 07, 2011 | 2001 Jeep Grand Cherokee

1 Answer

I replaced the master cylinder and brake pads and my brakes still dont work on my 1998 chrysler sebring


Have you tested your brake booster and your calipers?Your brake booster doesn't make any noise, and it doesn't use any electricity or gasoline, but it ensures that you can stop your car with only a light touch of the brake pedal. Things weren't always like that: before the invention of the vacuum brake booster, cars still stopped. It's just that you had to really stomp on the brake pedal. The modern brake booster is an ingenious device that operates using something that your engine generates whenever it's running: vacuum. The brake booster takes engine vacuum via a rubber hose that runs from the intake manifold, and the brake booster uses that vacuum to amplify the pressure you put on the pedal. A light application of the brakes is translated by the brake booster into significantly more pressure on the brake master cylinder, ensuring that your car stops quickly. So what happens to the brake booster if your car stalls, resulting in a loss of engine vacuum? Early designers realized that gas engines were hardly foolproof, so they designed a little check valve into the brake booster circuit. The brake booster stores enough vacuum to provide full boost for two or three pedal applications even after the engine dies. The check valve on the brake booster is what keeps that vacuum from leaking out. And speaking of leaks, that's the reason most brake booster units have to be replaced. As your brake booster ages, the rubber seals and diaphragms that hold the vacuum tend to wear out and crack. If the brake booster can't hold vacuum (despite the check valve's best efforts), its time is up and you'll need a new or remanufactured new brake booster.

Jun 14, 2011 | 1999 Chrysler Sebring

2 Answers

Where is the brake booster vacuum line on the 89 toyota camry?


Booster line will attach to back side (firewall side ) of booster chamber.

Should find a metal elbow coming out of the booster chamber that the vacuum line will slip over.

When you look at the booster chamber from the front, the location of the line should be at approx. 9 o'clock (as if looking at a clock dial)

Jan 24, 2011 | 1989 Toyota Camry

1 Answer

Stalls when pressing brake peddel


check for a faulty booster check valve. it is on vacuum hose to booster. you should only be able to blow on only one side, if you can blow through both sides then it is bad. the check valve holds the vacuum in booster. if bad you will lose vacuum. The check valve keeps the vacuum in the booster from leaking back into the intake when engine vacuum drops because of high loads or when the engine dies.
The symptoms would be no power boost when you turn the engine off or when the engine dies. Step on the brake with the engine running and note pedal position. Turn off engine and step again and the position should be the same. If the pedal is hard and higher then the check valve or booster is bad. have a good day!!

Nov 10, 2010 | 2003 GMC Yukon

1 Answer

How do I change my brake power booster in my 1989 Regency 88? My car does start and runs good, until you put it in gear and hit the brake. My brake petal is very hard to push. It will kill the engine when...


First inspect the vacuum check valve and the booster vacuum grommet for any leaks, even a pin hole in the check valve can also cause that to happen.

If the vacuum line to the booster is tight and has no air leaks, and no air leaks are in the vacuum check valve, then replace the booster unit.

Apr 19, 2010 | 1988 Oldsmobile Regency

1 Answer

Brakes problem


Check the hose going to the brake booster out under the hood. This booster is black and round and will be on the drivers side at the very back. there is a vacuum hose going to this from the engine, if there is no vacuum at the booster then the brake pedal will be very hard and often times harder than the older manual brakes. Inspect the hose and make sure there are no cracks in it and then start the car (in park w/ the emergency brake on) remove this hose from the booster. The valve that has the hose going to it which goes into the booster is a check valve (remove this with the hose by twisting and gently pulling to you at the same time) check and see if vacuum is coming thru the hose. If nothing or very weak then remove the check valve from the hose and see if the vacuum increases and many time will cause the motor to stall, if this happens then go to your local parts store and get a new booster check valve. If there is still no vacuum then you have a problem where the hose connects to the engine intake manifold.

Apr 06, 2009 | 1991 Jeep Cherokee Limited

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