Brakes 2001 silverado Z71

[Brent Overton]

I have a 2001 silverado and when you go to apply the brakes sometimes it feels that you just won't stop but then all of a sudden the brake seems to activate.(very scary)(even at low speeds)

Any help would be appreciated

Thanks

[juma33]

its normal if you mean it seems to delay for a second in real panic stop. That feature is built in to allow the rear drums to activate with front discs at the right time. If your truck has rear discs too, you can modify the metering in the combi-valve and all brakes will slam on like right F now.
juma

[LoneWolf3]

I have a 2004, All I can say is that it has to be the fact that they are computer controlled and prevent the lock up of a light rear end, other than that, anti lock you don't pump, you hold apply and continue mopre pressure until stopped, it is something you ahve to get used to, take on a dirt road and lay on them, or a abandon blacktop at 60.

[Sonny01]

Brent...does the ABS system kick in and release your brakes at a slow speed?

[juma33]

What is called brake fluid metering is the issue. The combi valve that your reservoir sets on is designed for front disc, rear drum. The metering of the front brakes is such that the front brake circuit is about half blocked to give the rear drums time to engage. This results in a scary second or two while you wait for the front brakes (most of your braking power) to engage. If you have rear discs, you can go into the combi-valve and modify the metering to get immediate engagement. If you have drums in the rear, start driving further ahead and avoid situations where you might have to stop quick.

juma

[Sonny01]

Juma...how do I modify the combi-valve?
Sonny

[juma33]

here isa thread on the impala forum that describes the metering mod.
http://www.impalasuperstore.com/nais...s=metering,mod

here's another that describes both the balance mod and metering mod:
http://impalassforum.com/noncgi/ulti...;f=23;t=001099

the only thing that should be done first is make sure the 99 combi valve part number is the same as the '00 and higher 4 wheel disc models. If it is the same part number, chevy took the usual shortcut and just gave us the same old hardware with new brakes.

juma