Brakes

KJANES389

MEMBER
2006 CHEVROLET SILVERADO
5.3L
V8
4WD
AUTOMATIC
180,000 MILES

Service brake booster warning comes on but my brake pedal is hard and holding also when I pull the check valve on the booster it sucks in air and if I pull the hose while it’s running it runs really rough. Is there any test you can do on the booster to check it or how to I get rid of that warning? Brakes work fine

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

When you remove the hose, you are creating a large vacuum leak. That is why the engine runs really poorly. As far as testing, the brake booster is a vacuum operated device. The way to check them is by applying a vacuum to them with a vacuum pump (with a gauge) and seeing if the pressure drops.

By chance, have you tried checking if there are diagnostic trouble codes? Also, there is a vacuum pump mounted on the booster. Do you notice if it is working?

Do me a favor. Take a look at the picture I attached below. Let me know if that is what you are seeing on your truck. I ask because based on your description, it sounds like you have a vacuum assist brake booster. However, they also used what is called a Hydro Boost system on some of these. Brake assist is done by the power steering pump.

Let me know.

Joe

See pic below.

Image (Click to make bigger)