Brake Question

[sixinthestix]

Mornin',

 

I own a 02' 2500HD 6.0 EC LB - right before coming to complete stops, i get this vibration in the brake pedal, and the noise almost sounds like a small air compressor running. I was thiking i had a warped rotor or such, but then this happend - was in Tenn, inching through the parkway @ cades cove, when the noise occured, vibration started, but since i wasnt coming to a stop nor was i speeding back up, the noise just kept going until it suddenly stops and my ABS light pops on, amazingly the noise and vibration did not occur after the ABS light prompted itself (ABS resets after turning ignition off/on). So now i am pushed to assume i have an ABS sensor or something to that nature to blame for this problem? I figured i'd toss it up to the abundant knowledge on the forums that i have read for a while now, but never joined.

[masterp2]

Mornin',

 

I own a 02' 2500HD 6.0 EC LB - right before coming to complete stops, i get this vibration in the brake pedal, and the noise almost sounds like a small air compressor running. I was thiking i had a warped rotor or such, but then this happend - was in Tenn, inching through the parkway @ cades cove, when the noise occured, vibration started, but since i wasnt coming to a stop nor was i speeding back up, the noise just kept going until it suddenly stops and my ABS light pops on, amazingly the noise and vibration did not occur after the ABS light prompted itself (ABS resets after turning ignition off/on). So now i am pushed to assume i have an ABS sensor or something to that nature to blame for this problem? I figured i'd toss it up to the abundant knowledge on the forums that i have read for a while now, but never joined.

 

hello and welcome. By any chance do you have oversized tires?

 

What you are experiencing is an ABS malfunction. Your ABS is kicking in, because it is recieving bad information. it thinks you are locking up, and you are not. It is a very dangerous situation, as your ABS is letting you roll when you want to stop. (if it is resetting, pull the abs fuse until you get this resolved)

 

The ABS deactivated itself, as it is trained to do, and you got the light.

 

Basically, you have either

 

1. tire size issue

2. sensor issue

3. dirt affecting sensor issue

4. calibration issue

 

if you have tires under 33" diameter, i would eliminate 1. above. Perhaps look for ice/mud on sensor.

 

BTW, the sensors job is to detect when the wheel has stopped rotating. If you still have forward speed, but the wheel has stopped rotating, then ABS is suppose to kick in. That is the vibration you feel, and is normal to feel when you mash the brake in a panic stop. But not in your situation.

[sixinthestix]

Thanks for such a quick response masterp2, and to answer your question im not running oversized, just 265/75's. I'll pull that fuse out asap, then i'll hunt down that sensor and give it a look. Thanks for the help and the welcome.

[Pancho]

For those that removed the ABS fuse - is there any way to disable the resulting ABS and Brake light that appear on the dash? Thanks in advance for any reply.