How to replace a vacuum booster

You have a bad vacuum booster. The diaphragm in the booster is ruptured resulting in vacuum loss and no power assist to the brakes. Do not drive in this condition, loss of control (stopping) hazard exist.. Replace Power Brake Booster. Since replacement of the booster requires removal of the master cylinder, replace the master cylinder as well, It is old (2003) and time for replacement

If your truck has a brake booster, I suspect the vacuum hose to the booster has gotten fuel into it or just gotten old and is collapsing inside.

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.

Most diesels use a belt driven vacuum pump to supply brake booster vacuum. See if vacuum is present at the hose on the booster can fitting. that is an old vacuum pump(1996) replace it.

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.

I would check the medium sized rubber hose that goes to the brake booster from the inlet manifold as it can swell internally and prevent vacuum getting to the power booster. Replace if necessary. I would also check all those pesky little rubber vacuum hoses that are used for pollution control. They tend to go hard and split where they connect to the metal piping if they are over 10 years old, allowing air / vacuum leaks into the inlet manifold. It could also mean that the rubber diaphragm inside the brake booster has developed a leak and causing loss of power assistance.

yes could be,also check for vacuum leak going to booster or leaking wheel cylinder

You may have a vacuum leak at one of the vacuum hoses. Also, the carburator may need rebuilt. Make sure the base idle is not too low.

Here this is an old technic but a goody, run the engine and get a squirter bottle with soapy water and spray around the base of the carby, manifold, air connections etc, if you hear the whisteling stop or the engine change in its running while doing this, then you can narrow your find., {a can of wd40 works as well}, remember we are here to help as best we can, good luck

Most likely your vacumn power brake booster has failed. It is not rebuildable. You will need to buy a new one.