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Abs Come On At Slow Speeds?

MR1911

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MR1911 Enthusiast

MR1911

Posted
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Ok I'm having a issue with the brakes on my 2000 GMC Sierra 1500, the abs keeps kicking on at slow stops as if I was sliding , on a flat straight road even into a parking spot . If i use them harder to come to a stop then it does not do it only slow as in 15 mph and below . Brakes are maybe a year old front and rear... rotors, pads, fluid both calipers in rear . No abs light on dash , no codes for abs either . I dont want to just yank the abs and send it off to be fixed to absfixer if its not that so what else could be causing this ?

 

As of now i pulled the fuse for abs but the snow is coming so I want to get this fixed ASAP . I live on a big hill and that abs has save my butt every winter since she was new coming down that hill in the snow and ice .

tylerjenkins92@aol.com Senior Enthusiast

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Posted
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It's one of the two front wheel speed sensors, they were a big problem back then. You have to take them out and sand the sureface down and clean the sensor up good and it should work right then.

MR1911 Enthusiast

MR1911

Posted
  • Author
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It's one of the two front wheel speed sensors, they were a big problem back then. You have to take them out and sand the sureface down and clean the sensor up good and it should work right then.

 

 

How? its all part of bearing assembly , I did the pass side a few years back and it all came as one . Is there a way to take it apart ?

Tweeter400 Enthusiast

Tweeter400

Posted
Posted

Ironically, I just jumped on the forums after a long hiatus to research this exact same issue with my 2006 silverado.

After much research I found TSB #030525007 which tells of this exact issue. I haven't had mine apart yet to find out, but I have heard

of many people breaking the sensor trying to get them out. Is there a trick to this? Pics would be awesome too if anyone has them!

 

Thanks!

ChevyTech77 Senior Enthusiast

ChevyTech77

Posted
Posted
Ironically, I just jumped on the forums after a long hiatus to research this exact same issue with my 2006 silverado.

After much research I found TSB #030525007 which tells of this exact issue. I haven't had mine apart yet to find out, but I have heard

of many people breaking the sensor trying to get them out. Is there a trick to this? Pics would be awesome too if anyone has them!

 

Thanks!

 

If you grab the sensor squarely, with a pair of channel locks, then twist back and forth while pulling straight up, they will come out ok. I've done literally hundreds of these repairs and only ever broken two. Both of those sensors were siezed tight in the hub bearings so they were going to break, no matter what I did.

Tweeter400 Enthusiast

Tweeter400

Posted
Posted

Thanks ChevyTech for the tip! Do you usually find that cleaning the corrosion/rust off fixes this problem, or do you usually have to replace the sensor?

TYPE GENDY Enthusiast

TYPE GENDY

Posted
Posted

I had the same problem for a year, i just had the fused pulled out but i did not like having the ABS disabled. So i went and got a new sensor at napa for about $60...put it in one side, put the truck back together and still had the problem. Then i took the other side out, put the original one i removed in the other side, and bingo! Feels soo good to not have my ABS lights on anymore :lol:

ChevyTech77 Senior Enthusiast

ChevyTech77

Posted
Posted
Thanks ChevyTech for the tip! Do you usually find that cleaning the corrosion/rust off fixes this problem, or do you usually have to replace the sensor?

The rust build-up can bend the sensor. When you remove it, make sure the mounting tab isn't bent. If it is, you need a new sensor. Otherwise clean, protect and go. :uhoh:

 

Also, for those of you that have replaced a hub bearing on just one side with an aftermarket bearing, that will

do the same thing as the rust build up will. The air gap between the sensor and internal tone ring in the bearing

will be different side for side causing the ebcm to think that the front wheels are rotating at different speeds.

Timken hub bearings are available aftermarket and are the same bearing that GM uses in factory assembly.

MR1911 Enthusiast

MR1911

Posted
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I changed both sensors out with parts from napa ( borg /warn. parts I believe ) this weekend and all is working again . I did pull the codes with my HPTuners software and came up both sensors as being bad but assumed it was not the issue and was abs unit but it had no codes for abs ,which is why i posted . Never new you could just get the sensors alone :lol: . I really dont know what happen here as both old sensors looked clean and there was no rust on the pickups inside either. The grease inside even looked fairly clean so I dont get what happen other then maybe the wire itself going to across the A arm had a short from going up and down for 10 years .

 

Just a side note to post above , when I replaced the passenger side wheel bearing hub about 4 years back it WAS a Timken as I always use Timken parts if there is a choice . Both sensors that came out said timken and also had the same part numbers on them so that was not the issue here but could see how it could be as you stated so I agree , and would advise anyone to change both sensors at the same time if your not going to use whats in there stock .

 

Thanks to everyone for pointing me in the right direction its good to have my ABS back .

ChevyTech77 Senior Enthusiast

ChevyTech77

Posted
Posted

It's not a difference in wheel speed sensor part numbers, its a difference in sensor to tone wheel air gap tolerances.

 

Glad you got it fixed though. :lol:

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