Master cylinder problem or power booster problem on 2006 Chevy Silverado 5.3 L how do you know where the problem lies

Most times a booster will have a air leaking, hissing, vacuum leak sound, sometimes will sound off even when pedal is not pushed and make noise all the time, others just when hitting brake pedal and will or can go to floor, others to hard to push. Master can have all sorts of symptoms too, can not build pressure is on of the most common. The way you describe it I would look into a wheel cylinder fluid leak, and leaks around calipers and fittings and check lines and your brake fluid master for low fluid level.

If no leaks and no sounds from booster, check booster vacuum line from motor and check valve, there is some easy ways to check valve and booster with simple test may can find them on net or youtube or I can explain if none are around. If it passes those test then I would suspect the master cylinder, I would also check you rubber lines for leaks or if brake fluid is turning black (or very dark.)

Sounds like you have fluid leaking and/or need your brakes bled. A bad booster will make the pedal hard to push

Guru9C2Q look at this site may help: Symptoms of a Bad or Failing Vacuum Brake Booster Check Valve URL: https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-vacuum-brake-booster-check-valve

How to Test a Brake Booster Check Valve: Park the vehicle and open the hood. Locate the vacuum booster. This is a dome-shaped assembly that is mounted to the rear wall of the engine compartment on the driver's side, in-line with the brake pedal. Locate the vacuum hose that runs from the engine intake manifold to the vacuum booster. Trace the vacuum hose back to the engine intake manifold connection. Undo the hose clamp or clip using pliers or a screwdriver and slip the hose off the connection point. Blow air into the hose. Use your mouth if you don't mind eating a bit of engine dirt. Alternatively, slip an aspirator bulb over the hose end and squeeze. In a pinch, turkey basters make great aspirators. If the check valve is functioning properly it should prevent you from blowing air into the hose. Suck air out of the hose. If the line is not blocked and the check valve is functioning properly you should be able to easily suck air out of the hose.

Here is Brake booster test & more Copy & paste URL to new browser window: http://www.roadkillcustoms.com/hot-rods-rat-rods/hot-rod-power-brake-booster-test.asp#axzz4bpb4MBdo

Master brake cylinder test: http://www.roadkillcustoms.com/hot-rods-rat-rods/hot-rod-master-cylinder-test.asp#axzz4bpb4MBdo

u have air in your brakes

Why my antlock brake system keeps kick on

A 2006 Chevy 1500 has a self bleeder under the truck mounted to the frame. It's pretty much under the drivers seat backrest. You can't bleeds the brakes yourself on these models unless you have a fancy $1,500.00 Snap on code reader, or equivalent, that not only reads but it comunacates to the vehicle as well. I had a bad rear wheel silinder and didn't know it. Yeah, I should have noticed the fluid but I bought the truck used and this problem was so old the apparent leak didn't show any longer. I replaced front and back brakes, master cylinder, booster because of the behaviour in this situation and nothing. I finally traced the lines out thinking I might have to replace some when I noticed the, what looks like an air ride system. I wanted to buy the right computer but ended up using a friend's that owns a shop. In this particular truck and situation I would take it to a mechanic and let him fix it. Good luck

Needing to see if a brake master cylinder on a 1996 Chevrolet Silverado will fit on a 1988 GMC sierra both have 350 motors

I have a 2008 silverado 1500 and my master cylinder went bad. I replaced the master cylinder and booster because it had fluid it in it. Now a month or so later, all my lights came on and the reservoir is almost empty. I removed the master cylinder and noticed all of the fluid is in the booster. Im thinking maybe its a faulty master cylinder?