kickstartjoe

When I am moving very slowly, the brake pedal sort of goes down too far, and there is a roughness, almost like grinding but with no noise. The bad part is, the truck doesn't want to stop. I press down very hard on the pedal, and it finally stops.
The brakes work fine in every situation except this creeping mode. It happens, for example, if I am easing into a parking place.
The truck is an automatic, and the pads are all ok. No sensor lights have come on.
Advice is appreciated on this problem.
Joe

in2pro

That sounds like a vacuum booster gone out, what year and how many miles?

kickstartjoe

Sorry for the delay in responding; been out of town. The truck is a 2001 4.8L with auto tranny and 152xxx miles.
A friend with some mechanical skills said he thinks the problem is with something to do with the ABS system. He said the symptoms do not point at the booster. He could certainly be wrong.
Thanks,
Joe

BigScott5150

i tend to agree with in2pro. i had a similar prob with my 98 gmc sierra.
i bought a booster from the junk yard and it's been good to go for several years now. might be something else like your friend said but the booster is a good place to start and would be cheaper.

jzinsser

My wifes vehicle had something similar happen (pedal pulsed like abs kicking in, however it lacked the electronic sound then pedal would get close to fully compressed at verry low speed. I checked the pads had the roters turned incase they were warped all calipers fine too... long story short I had the dealership replace the tone ring pob. solved investigate that baybe helpful.
good luck

EvansBlue

Try pushing it all the way to the bottom when this happens. Does the ABS light come on for a second or two?

kickstartjoe

No, the ABS light never comes on. When easing into a parking place, the pedal sort of collapses and there is a grinding feeling in the pedal, with some rough, but not grinding, noise. I release the pedal and press hard on it and the truck stops, albeit harder than it should. Again, this only happens when I am moving very slowly, like into a parking space.

kickstartjoe

I sort of fixed the problem by removing the fuse for the ABS. In researching on the Web, I found it is not an uncommon problem for these trucks to have problems with the ABS. These are generally caused by water getting into the sensor box, necessitating a new one, which is expensive. Additionally, if I put one in myself, I would have to bleed the brakes, and I detest that job.
The brakes work just fine now. I just don't have the ABS to assist in cases where it is necessary. At least I now don't have to worry about running into someone or something because of the problem the truck did have.
Joe

suzuki-guy

I can tell you exactly what it is right now its your hub assembly jack up the truck and hold your hands at 6 and 12 oclock positions if there is play in your wheel that snot coming from the ball joint its your hub assembly(this sounds weird like it has nothing to do with your brakes but your abs is tied in your hub assembly mine did the exact same thing on my 2001 and the abs never light came on until i pulled the fuse)

kickstartjoe

Is there a repair to the hub assembly possible that will fix the problem?
Joe