Brake problems on 1988 Chevy 1500

If the brake booster has failed- you replace it

Check the booster- check valve- for leaks

Nothing to do with your driving habits

The vehicle is 27 years old

Hard brake pedal when applied with the engine running. A quick test for the vacuum assist booster is to shut off engine, pump brake pedal 3 or 4 times and hold on the last pump, start engine and see if pedal drops a bit....if you detect a problem with booster you should check for adequate engine vacuum supply to booster when idling . You can sometime hear a hissing or air leaking when applying brake pedal with engine running if booster is defective

NO. the vacuum is used to make the brake pedal easy to push, power brakes. the pedal would be hard without vacuum, that is why the pedal gets hard with the key off and engine not running. the problem you are having is more of a hydraulic problem.
Have the brakes checked asap. the brake system may have a leak causing the pedal to go low. check the fluid level and if it is low or empty then there is a problem, could be a rotted brake line leaking or a wheel cylinder leaking.

the booster is the problem, or a hole or leak in vacuum line to booster check the check valve also ! from manifold. heres the symtoms of a bad brake booster. primary symtom is a hard pedal on application, to test booster. pump brakes several times with engine off. to deplete stored vacuum. turn on engine with pushing slightly on brake pedal. you should feel the pedal fade away abit and then become firm. but not hard. if you feel nothing at pedal when engine starts, brake booster is not working! check the vacuum lines first!!

Ok many people have this problem when they do brakes that ABS equiped. First of all make sure that all your connection are tight at the calipers. Check and make sure you have no visible leaks at all every where on the vehicle. Second alot of people do not know that the vehicle must be running when you bleed the brakes when the vehicle has ABS brakes. So the solution to your problem is very simple check to make sure master cylinder is full, then start your vehicle and have some one pump the brakes then hold down and open bleeder valve. You need to do this several times with ABS brakes,make sure you continue to check master cylinder fluid level continuously. Always start bleeding the brake that is farthest away from master cylinder first then continue to work your way to the closesest. Remeber when bleeding brakes when equiped with ABS the vehicle must be running to allow the ABS pump to run and bleed as well.

well, a hard firm pedal, usually indicates a bad brake booster or a vacuum leak to booster or the vacuum check valve, on booster. TO TEST BRAKE BOOSTER; pump brakes several times with engine off to deplete stored vacuum. turn on engine with pushing slightly on pedal. you should feel the pedal fade away a bit and then become firm, but not hard. if you feel nothing at the pedal when engine starts the booster is at fault. good-luck !!

It appears that you have lost the vacuum assistance that works the power booster for the brakes. It is most likely that the vacuum hose that connects from the vacuum pump (which is usually located on the rear of the alternator) to the power booster has gone hard and split where the hose attaches to the metal piping. Check the hose for leaks or splits and re-terminate or replace as necessary. If the hose is OK then the problem could be that the vacuum pump is faulty or the rubber diapraghm inside the power booster has become faulty and developed a leak. A brake specialist would be the best option to sort out these latter problems.

In the engine compartment, locate black vacuum hose that runs from brake booster check valve to intake manifold, there will be a small vacuum hose attached to check valve at the power brake booster check valve. This is the vacuum line going to the heater control unit,check the hose all the way to the firewall, repair any leaks you find. And that should take care of your problem.......GOOD LUCK

could be booster, could be air in system, could be master cylinder. Check reservoir. If it is out, you have leaks and air in lines. If no, listen for air leaks under dash as you push pedal. If air leak, replace booster.
If no air leak, check for vacuum at hose going into booster. If no vacuum, check hose connection to intake manifold.
If no leaks and booster is good, suspect master cylinder.

Let me know if you have questions.

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.