Brake Pedal Travel on NBS, is this normal?

[Bluehole]

2000 Silverado 2wd. I just had my rear brake pads replaced yesterday with the original type ceramic pads. Today I noticed that when my truck is running, but not moving...I can apply semi-firm pressure on the bake pedal and it will slowly travel almost to the floor. The pedal don't actually touch the floor mat, but it gets very close(4-5 inches of travel at least). Unfortunately, I don't know if this is normal or even if it did it before I had the new pads put on. As far as driving goes, it stops great and the pedal doesnt' travel far at all to make an easy or hard stop. I checked the brake reservoir and it's full of fluid. Is this normal or do I need to take it back to the shop that did the work.

 

Jason

2000 Silverado Xcab 5.3 2wd

[TarheelZ]

I'd take it back to the shop...sounds like they didn't bleed the lines completely.

[RyanbabZ71]

same thing happened to mine when I changed the rear brakes last weekend. Didnt feel right so I bled the brakes again and it is back to normal

 

Also did you put ceramics on? Do you do any towing? I read an article recently that ceramic brakes are back if you do any hauling/towing

[Bluehole]

The largest load I've pulled so far is 5 people in the cab, 3/4 of a rick of wood in the bed and 10 canoes on a trailer, and camping junk for 5 people. and Obviously not much weight at all.

 

Actually I don't even know if I had ceramics put on or not. I just when to the dealer and said I want to buy the same type of pads that came on my truck from the factory. I drive like a maniac and still got 80,000 miles out of my first set, so I wanted to go back with what was on there. I had another shop besides the dealer actually put the pads on.

 

-Jason

[frdfandc]

Today I noticed that when my truck is running, but not moving...I can apply semi-firm pressure on the bake pedal and it will slowly travel almost to the floor.

I hate to burst your bubble, but your concern is a normal characteristic of most modern day brake systems. What is happening is that your brake booster uses engine vacuum to provide power to your brakes so when you apply the brake pedal, there is minimal effort. When you are at idle, the engine, lets say, makes 10 psi of vacuum. When you apply the brake pedal, the booster takes, for example, 8 psi of vacuum. That leaves 2 psi of vacuum.

 

Now when you are driving and apply the brake pedal, the engine RPM's are higher, therefore creating more vacuum and giving you a firm pedal without alot of down travel. Because the booster only uses so much vacuum, no matter what engine vacuum is. Changes in idle due to electrical loads or a/c cycling on and off can cause idle to fluctuate, therefore can change the amount of engine vacuum to the brake booster.

 

My 2003 Z-71 with 14,000 miles does the same thing. If you were having a brake pedal that dropped to the floor very quickly, you would still have air in the brake system.

[Bluehole]

I hate to burst your bubble, but your concern is a normal characteristic of most modern day brake systems.

My 2003 Z-71 with 14,000 miles does the same thing. If you were having a brake pedal that dropped to the floor very quickly, you would still have air in the brake system.

Thanks for bursting my bubble. That's just the info I was looking for. I had no idea if it was normal or not.

 

Thanks,

Jason

[frdfandc]

Not a problem

[tryn2lrn]

Good to know. If that's the case while in Park with the emergency brake on you should be able to lightly rev the engine a little, maybe to 2000 rpm and get a firm pedal?

[Bluehole]

Good to know.  If that's the case while in Park with the emergency brake on you should be able to lightly rev the engine a little, maybe to 2000 rpm and get a firm pedal?

I'm no mechanic, but I'm not sure what the parking brake would have to do with pedal firmness. Maybe it's a Chilton's manual safety thing "always disconnect the negative battery cable" no matter what your heck doing.

 

-Jason