# abs problem and 4 wheel problem



## bru z71 (May 10, 2009)

2005 silverado 1500 z71 ok so this has ben going on for weeks now and i cant find the answer when i am driving at low speeds like 5 to 10 mph and i hit the brakes my abs kicks in i have no abs light no codes fault i replaced my 2 front wheel bearing sencers and the bearings them self are not more then a yr old is there some how i can trouble shot this?

and once a while my 4 wd service light comes on and if i hit the switch it will not go into 4 wheel drive it has power to it the lights on 
any ideas ? thanks and what a bust for boston area this yr wtf
ussmileyflag


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## salopez (Apr 11, 2004)

I belive its your front hubs....when you brake you go an extra 20 ft at low speeds? I am getting ready to replace mine due to the same thing...working your truck in the salt. good luck.


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## peteo1 (Jul 4, 2011)

I had a 99 Z71that did the same exact thing. All I did was unhook the abs sensors and everything worked fine after that. I didn't have any abs after that but I had no problems braking either. I'm not telling you to go that route or even recommending it but that's what I did on my own truck. I wouldn't try it on anyone else's though. Just my .02


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## brad96z28 (Aug 21, 2005)

U need to clean/ grind down where the sensors go into the frt hub/bearings. Lots of rust can build up in a year. Use a file or grinde and make sure to coat with some sort of grease when re installing U will be all set for a long time after ur done. The rust pulls the sensor awyay from the tone ring in the front hub causing an erratic waveform at low speed. Ur 4wd could b one of several problems Most likelly the encoder motor. But I have seen server other things cause this issue as well.


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## Plowtoy (Dec 15, 2001)

I think the wheel speed input has too much of a difference and it is causing the abs to kick on when you apply the brakes. This could be caused by several things but most likely a failing wheel speed sensor, meaning you will most likely have to replace a hub if its a front that is failing. As far as the 4wd issue goes, the encoder motors are common issues, but some of them have a "sensor" that can be replaced instead of replacing the whole unit. Good Luck


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## lawnmedic (Jan 9, 2004)

This has been a common problem on these trucks. Follow "brad96z28"'s instructions...They even did a recall on my 01 Yukon for this.


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## acm1968 (Dec 10, 2008)

front bearing is bad very common i change at least 1 or to a year on my 02 thru 07 chevys when bearing starts to go abs sensor attached to it causes brakes to pullsate just before comming to a complete stop. i have gotten bad ones before advanced auto even changed there suppy from cheep to timkens . they are same for both sides so jack truck up and grab wheel from top and bottom and shake thus telling witch is bad . if both are still good u didnt put wire in same mounting position . meaning clip wire back in same hole on a frame


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## brad96z28 (Aug 21, 2005)

acm1968;1472756 said:


> front bearing is bad very common i change at least 1 or to a year on my 02 thru 07 chevys when bearing starts to go abs sensor attached to it causes brakes to pullsate just before comming to a complete stop. i have gotten bad ones before advanced auto even changed there suppy from cheep to timkens . they are same for both sides so jack truck up and grab wheel from top and bottom and shake thus telling witch is bad . if both are still good u didnt put wire in same mounting position . meaning clip wire back in same hole on a frame


Lucky my 04 has original bearings I clean them every couple years is all. Mine have also gotten play that was fixed by re torquing the axle nut. Wheel bearings dont need to have play to bad and 99% of the time the ones that have play dont affect the sensors. Its a rust issue that been a known problem for more then 10 years now.


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## leolkfrm (Mar 11, 2010)

you may want to consider flushing the lines with fresh fluid


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## bru z71 (May 10, 2009)

found the problem speed sensor in my transfer case i went threw my computer and my rear sensor is telling my comp that i am going 120 mph when i am doing like 30 mph i wasnt sure are there 2 sensors in the rear or 1 ? and my 4 wheel drive light was just a switch on the dash


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