Question about 2000 GMC Jimmy

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When i step on the brakes the engine idles fast, I think I need to replace my pb booster, is it a tough job?

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No, its not a hard job to do at all. Let's first determine thats the problem. Go out and pump up your brakes with the engine off. While your foot is still on the brake pedal, start the engine and your pedal should start to fall as vacum assist is cretaed in the booster. If this is happening your booster is not bad. Even if it dosn't, before you replace your booster ther is also a vacum check valve on the front of the booster that can go bad. Take the valve out of the booster and see if you can only blow through it one way, if so it's good and you will be replacing the booster. The hardest part of the booster is room and under the dash work. First remove the master cylinder, sometimes you can just unbolt from booster and leave lines hooked up and push out of way, depending on room. If not remove the brake lines and remove master and set to side. Nexte you will climb under dash,disconect pedal rod from peddale and remove the four nuts that mount booster to firewall. Climb out grab booster and remove. Installl in reverse order and be sure to bleed the lines of air if you remover master cylinder.

Posted on Sep 04, 2009

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It should when you push the brake pedal but only for a second or 2. if idles up and stays up then yes its bad, start,push pedal, and put ear under dash and you should hear it **** air. its not too bad, unbolt the master cylinder, has braided steel lines going to abs modulator, flop forward outa the way. undo vacume hose, then go under dash, take out rod to pedal pin, 4 nuts, and pull it out of the firewall. you do not need to bleed brakes if you do not undo a hydraulic line and be delicate with brake light switch on the pedal

Posted on Sep 04, 2009


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How to replace brake booster on 2005 Pontiac aztek

Step 1 - Locate the Brake Booster The brake booster is located adjacent to the master cylinder. There will be 4 mounting screws protruding through the booster. The booster is also attached to the brake pedal in the interior of the car. This is where you will start work in replacing the brake booster.
Step 2 - Remove the Brake Booster Start by locating the booster rod that goes through the firewall and is attached to the brake pedal on the interior of the car. Typically, there is a cotter pin that secures the rod to the pedal, but there may also be nuts. When removing any fasteners in the course of this job, make sure to retain the nuts, cotter pins, and various other fasteners as the new brake booster will not come with replacement fasteners.
Remove the fasteners, whether it is a cotter pin or nuts. Slide the rod off the brake pedal. Disconnect the vacuum brake line that connects to the booster. In the engine compartment, there are four bolts securing the booster to the master cylinder and firewall. Loosen and remove these nuts. Remove the nuts (there are usually 2 in addition to the 4 that have already been removed) that secure the brake booster to the master cylinder. Wiggle the brake booster away from the master cylinder. There is a seal between the two. You will need to keep this as the new part does not generally come with another one. Remove the brake booster.
Step 3 - Install the New Brake Booster Set the new brake booster on the four mounting screws. Tighten the nuts on the bolts to the master cylinder. Insert the push rod through the firewall. Start these by hand so that the threads are not ruined. Reattach the vacuum hose, then the nuts to the 4 mounting screws. Reattach the push rod to the brake pedal by whatever means it was originally secured with, whether by cotter pin or by bolts.
Step 4 - Bleed the Brakes You will need to bleed the brakes after replacing the brake booster

Jul 11, 2016 | 2005 Pontiac Aztek

1 Answer

1997 kia sephia 1.8 liter 5 speed when I step on brake engine idle go up and down take foot off its stopi

Highly possible brake booster has,failed. You can pinch off the vacuum line and press on the brakes if idle does not change ,replace booster,if idle still changes take to a mechanic. Do not attempt to drive it with line pinched

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1 Answer

High and low headlight and my idle goes low when i step the brake

On power brakes, a leaking vacuum booster can cause such a vacuum leak to engine that idle is affected and headlamps dim because idle is so low. To test, remove and plug hose to booster.

Feb 12, 2015 | Cars & Trucks

1 Answer

Step by step instructions for replacing brake booster on a 1999 Toyota Camry

its my pleasure to answer your question how to replace the brake booster :
1 With the engine off, step on the brake pedal several times to relieve the brake booster of vacuum.
2 Press the brake pedal down and start the engine. Verify that the brake pedal sinks slightly. Turn off engine.
3 Remove the vacuum hose from the brake booster.
4 Remove the brake lines from the master cylinder. Remove the master cylinder from the brake booster. Plug the fittings to prevent brake fluid seepage.
5 Disconnect the brake pedal from the push rod.
6 Have an assistant hold the brake booster from inside the engine compartment. Remove the nuts that hold the brake booster to the firewall. These nuts are usually located under the dash on the interior of the firewall.
7 Remove the brake booster.
8 Install the new brake booster to the firewall. Tighten the mounting nuts.
9 Connect the push rod to the brake pedal.
10 Connect the vacuum hose to the brake booster.
11 Attach the master cylinder to the new brake booster and reconnect the brake lines.
.12 Bleed the brakes at the master cylinder.

Oct 04, 2013 | Cars & Trucks

1 Answer

I have a 96 kia sportage 4wd and its back tires are spinning even when the brakes are fully pressed. its also idling faster then it should. It wants to idle fast first starting then it calms down. anyone...

Sounds like a bad master cylinder, if brake fluid is black, change it (1996, ITS TIME) .The brake booster is probably leaking vacume causing high idle, check this by disconnecting the large hose from booster can and plug it with your thumb. If the engine idles down, the booster is bad and must go on ahead of the master cylinder. After replacement back brakes will have to be bled.

May 19, 2017 | Cars & Trucks

1 Answer

Code p0505 fast idle

look for a vacume hose or intake leak squeeze vacume line to brake booster and if idle changes if so bad booster

Aug 13, 2012 | Jeep Grand Cherokee Cars & Trucks

1 Answer

Idle good when cold, hotter it gets the worst it idles especially when sitting at stop lights

simple test for a vacuum brake booster
star and run the engine at idle without applying the foot brake
if it gets worse when the foot brake is applied , it is a vacuum leak in the booster ( replace the booster )
otherwise check for failed vacuum hoses including under dash control lines , vacuum leak at the manifold or EGR unit

Apr 16, 2017 | Chevrolet Astro Cars & Trucks

1 Answer

When car is idling with AC on and power brakes applied, the idle goes back & forth between fast & slow. The AC Up Idle VSV and the Idle Up valve itself are both working. The brake booster check...

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.

Mar 10, 2011 | 1994 Toyota Pickup

2 Answers

I have a hard brake peddel almoust have to stand on them what could this be

You no longer have vacuum assistence. The brake master cylinder is mounted on the brake booster which uses vacuum generated by the engine to "help" you push the brake pedal. On diesel engines there is normally a vacuum pump on the rear of the alternator which generates this vacuum. On petrol engines the vacuum is generated by the engine itself. Follow the pipe from the booster to the inlet manifold or alternator(diesel) and check for leaks along the whole length and at the joints. Replace the pipe if leaking. If no leaks are found the booster needs replacing. If you have a diesel engine, check the operation of the vacuum pump first before replacing the booster. Make sure the alternator is turning(belt in place) at idle. Disconnect the pipe at the rear of the alternator and hold a piece of paper over the pump opening to check operation. Do not use your hand as this will result in injury even with the engine at idle. Replacing the booster will see you upside down under the dashboard swearing, pleading and begging because that's where the bolts are that hold the booster in place. The master cylinder needs to be removed from the booster before the booster can be pulled from the engine bay.

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