Monday I noticed that my brake pedal didn't feel right. I went to ease into the brakes and it felt like my pedal was locked. I pushed harder and the pedal popped and the brakes worked. It has been doing this all week consistantly. It acts fine when the engine is not running or when I first start it. My question is, could it be the hydroboost or the ABS pump? My steering is fine, but my abs and brake light have been on for some time now.
Has anyone experienced this? If so please chime in so I kinda know what parts to order to fix this problem.

 

If you have power steering the pump is fine. The hydroboost unit can be checked superficially by starting the engine, then shutting it off. Then press the brake pedal three times in a row, and if the pedal swings down and the brakes apply smoothly, you are likely OK. If the pedal works once and then sticks, or it sticks immediately until you really nail it, the accumulator has likely perforated and lost its charge.

The accumulator is the canister that sets behind the master cylinder and is on the top front edge of the hydro boost. If the accumulator fails it is time to rebuild the hydroboost. Unless you have good instructions or have done this rebuild before, it is best to replace the entire hydro boost unit with a rebuilt. If the accumulator fails it usually means contamination in the brake fluid, and the rear seal on the shaft that connects to your brake pedal will soon follow.

If the brake pedal is smooth, then it is unlikely you have a problem with the hydroboost. Then check the combination valve. It sets beside and below the master cylinder, to the fender side, and has a button on the front. Have someone work the pedal with the engine running and watch that button. If it the button is not working in and out with the pedal, you likely have a failed combination valve.

If that does not solve the problem, have a brake system code scan done. The brake system generates its own unique codes and are very helpful in diagnosing trouble. It is possible you may have a stuck wheel cylinder, and the codes will greatly assist the diagnosis. You can also diagnose each wheel cylinder manually by jacking up each wheel and spinning it while you have someone tap the brakes. If there is any delay in braking or a snapping sound, you will have located the culprit.