04 Armada Brake Booster replacement

There is actually an adjustment on those to set the amount of pedal travel required to activate the boost. Sometimes the diaphragm fails or cracks and it no longer works. There should be 2 or 4 fasteners holding that whole unit to the firewall and after you pull the master cylinder off, the booster should come off as well. Brake Booster Removal: What's the Trick to Getting the ... (2carpros.com)

Had the exact same issue with an 04 Cadillac srx. Replaced the booster twice...finally put my old "defective" master cylinder back on and brakes worked fine. Turned out the new master cylinder was bad...even though the symptoms point to the booster. Do check the vacuum hose going to the booster first though. Have seen those go bad and cause weird problems and it's the easiest thing to check first.

Toyota Sequoia's had a lot of problems abs wise> #1 clear codes with a factory software scanner. then drive it to see what returns. I can not see a brake booster setting 3 codes that are ABS/VSC problems #2 how does the brake pedal feel If it is high and hard pedal then the booster is bad if the engine speeds rise as pedal is depress and you hear escaping air the booster is bad. #3 ABS/VSC are supplemental systems to the normal braking soit will take longer to stop and a possible skid could occur. but you will stop leave more traveling space you should be fine.

That hard pedal is a sign of a vacuum leak on the brake booster.Check the vacuum hose on the booster for holes and with the engine running have someone push the brake pedal while someone else watches the hose to see if it is collapsing when the brake is applied.If it does that will be your problem.Replace the 3/8 vacuum booster hose.It will have to be the thick hose just for a vacuum booster or it will do the same thing if that is what is wrong.

Hello, You may have a bad brake booster, there can be a check valve in the feed line to the booster. You need to have a pressure check done on the brake booster. Be careful not to use any chemical which can dissolve rubber or plastic if you use a spray around the booster. A water spray may indicate a leaking booster if you test it with the engine running. The rpm will change from a leak.

The ABS system should show a "check light" if it is malfunctioning. The modulation inside the brake unit possibly could make noise.

The Traction control, if equipped, can activate a control valve in the intake system to limit engine RPM. When this system works, it shuts off intake air to slow down the engine when the system detects slippage in the rear wheels. If you have a toggle button on the dash to switch off the Traction control, turn the sytem off and try driving it and see if the noise goes away. Debris in the rear rotor "drum" brake could possibly blind a wheel sensor counting the revs and activate the Traction control

Idle speed control "motor" is a type of intake air control used to smooth out the engine. It operates in a air chamber and its the last thing I can think of that even remotely could make a noise.

check the vaccum hose that connects to the brake booster under the hood, also check the sensor on the brake booster. it could also be abad brake booster assembly

Double check the level in the master cylinder. If this is full the most probable is the vacuum booster. This is the large black cylinder directly behind the master cylinder which is operated by vacuum which when you apply mechanical pressure to the brake system, the vacuum assists you by pulling and making it easier to apply the brakes. If you can "stand" on the pedal and the vehicle stops, this is a most likely cause. 1 thing you can do to verify is to first locate the one and only vacuum line going to the booster and make sure there is no holes or no "hissing" caused by a vacuum leak. Let me know if you need further assistance or directions to replace.

Do you by any chance hear a hissing noise from under the dash? If so, yes, you have a bad booster. For it to do what you're saying, it would almost have to have a vacuum leak. However, if there is a problem with something in the ABS system, you should have an ABS warning light on. Also, ABS can make the pedal fade, but I've never heard of it making the pedal hard. Your diagnosis of a brake booster does sound likely, but I'll admit I can't be sure -- this is an odd one.

Brake booster or brake booster sensor

Sounds like two issue. The ABS unit might need replacement (known issue for ABS lights on) and the brakes need to be quality parts (ATE, Brembo, Girling, etc.) , not discount auto or pep boy type brakes. Those don't stop well. If the pedal travel is excessive, bleed the brake system first. If its still excessive, its most likely the master cylinder, not the booster (booster will make the pedal hard).