# Brake problem on 2500hd



## QuadRacer041 (Sep 1, 2003)

I have an 06 2500hd crew cab. Lately I've noticed that when I hit the brake the pedal it feels spongey right before the truck comes to a stop, real low wheel speed.What could that be? Air getting in the system somehow? I haven't had any service on the brakes done recently, I dont know how it could have started. Any ideas? I talked to a buddy of mine who is a mechanic at a dealership (not chevy though) and said that he thinks it could be an ABS sensor going bad. After he said that it kinda make sense because the action I get from the brake pedal when it happens feels like the abs is kickin in.
Any info would be greatly appreciated.


----------



## saintsinner84 (Feb 10, 2010)

i've that problem with my 2006 gmc 3500. but with the spongey feeling it would also turn on the antilock brakes but only on my front right tire. took it to the dealer and they said the abs sensors were corroded and they replaced them. but that didnt fix it. doesnt really bother me much because like you said its very low wheel speed, like 5mph and lower. and it doesnt make me slide it still stops where i want it too. but one of these days ill have to get it back in for service.


----------



## QuadRacer041 (Sep 1, 2003)

Was it done under warrenty? If not i'd go vack. Actually go back anyway so when its fixed you can let me know what it was, lol lol.


----------



## saintsinner84 (Feb 10, 2010)

no we bought the truck used w/o warenty. and as soon as i know i can loose my truck for 1-2 weeks and not have to worry about snow, i will take it back. but since my dealer seems to like to hold onto my truck for weeks at a time i cant chance it. and back when we had our old 1991 chevy 3500 dumper with a old meyer plow, we had a problem with our 4wd or the lack of. and we took it in to AAMCO to fix the 4wd and at the same time fix the 2nd gear syncro so i wouldnt have to double clutch into 2nd. and it snowed 2 times while it was there. and it turns out they used my truck to plow their lot. and on top of that they fixed the 4wd and the 2nd gear syncro but then the tranny whined like crazy from then on. so we ended up having to sue them and then we traded the truck in a year after.


----------



## QuadRacer041 (Sep 1, 2003)

This is what someone on another site posted for me:

i pulled my ABS fuse.... best thing i could have done, i was having the same kind of problem pulling into parking spots 
the only way to fix this other than just pulling the fuse and scrapping ABS all together is to replace both front wheel barrings. The problem is the ABS sensor is inside of the hub/barring assembly and as they start to wear, not get worn out, just wear, the grease starts to come out of the barring pack and gets flung all over the inside of the hub and lands on the sensor for the ABS.... and theres no way to take the sensors out of the hub, you just have to replace the assembly 
__________________


----------



## saintsinner84 (Feb 10, 2010)

does anyone know where this fuse it located, i'm assuming under the hood but i'm nowhere near my truck to check


----------



## ahoron (Jan 22, 2007)

Under the hood driver side its one of the big ones


----------



## saintsinner84 (Feb 10, 2010)

sweet consider mine fixed


----------



## tmltrans (Oct 18, 2004)

My 2004 2500HD had same problem, its a corrosion problem on the ABS sensor mounts moves them slightly out of position. Easy fix if you can take off without breaking anything. I had dealer do mine they did it while I was having oil change done, but if they break one or more while taking apart and your not still under warranty it could cost you new sensor(s).


----------



## B&B (Nov 4, 2006)

Super common issue in the rust belt regions. You can replace the wheel speed sensors until you wallet is empty and it won't address the root issue, which is rust buildup on the machined flange that the sensor sets on. After removing the sensor you have to thoroughly and VERY CAREFULLY scrape and clean the thin layer of rust from the flange. I state very carefully so you don't allow any debris to fall into the hub cavity. Be sure to apply some grease on the flange to reduce future corrosion as it only takes a .010 thickness of rust buildup to cause the sensor to loose it's tracking on the tone ring in the hub unit. Take twice as long to disassemble and reassemble the brakes to access the sensors than it does to actually fix the issue.

You can throw a fresh set of sensors in there while you have it apart if it makes you feel better (about $60 each) but they seldom go bad, it's virtually always the rust buildup that's the real cause.


----------



## QuadRacer041 (Sep 1, 2003)

B&B;998485 said:


> Super common issue in the rust belt regions. You can replace the wheel speed sensors until you wallet is empty and it won't address the root issue, which is rust buildup on the machined flange that the sensor sets on. After removing the sensor you have to thoroughly and VERY CAREFULLY scrape and clean the thin layer of rust from the flange. I state very carefully so you don't allow any debris to fall into the hub cavity. Be sure to apply some grease on the flange to reduce future corrosion as it only takes a .010 thickness of rust buildup to cause the sensor to loose it's tracking on the tone ring in the hub unit. Take twice as long to disassemble and reassemble the brakes to access the sensors than it does to actually fix the issue.
> 
> You can throw a fresh set of sensors in there while you have it apart if it makes you feel better (about $60 each) but they seldom go bad, it's virtually always the rust buildup that's the real cause.


Is this the front only or all 4 wheels?


----------



## B&B (Nov 4, 2006)

Applies to the front only. The rear wheels are monitored via a single channel by the vehicle speed sensor located in the trans on a 2X4 or on the transfer case on a 4X4.


----------



## EricD701 (Jan 19, 2007)

B&B;998485 said:


> Super common issue in the rust belt regions. You can replace the wheel speed sensors until you wallet is empty and it won't address the root issue, which is rust buildup on the machined flange that the sensor sets on. After removing the sensor you have to thoroughly and VERY CAREFULLY scrape and clean the thin layer of rust from the flange. I state very carefully so you don't allow any debris to fall into the hub cavity. Be sure to apply some grease on the flange to reduce future corrosion as it only takes a .010 thickness of rust buildup to cause the sensor to loose it's tracking on the tone ring in the hub unit. Take twice as long to disassemble and reassemble the brakes to access the sensors than it does to actually fix the issue.
> 
> You can throw a fresh set of sensors in there while you have it apart if it makes you feel better (about $60 each) but they seldom go bad, it's virtually always the rust buildup that's the real cause.


Also while you are cleaning that area if you or a helper hold a shop vac hose close to the area you are cleaning, that will help keep it from falling in.


----------



## B&B (Nov 4, 2006)

EricD701;998509 said:


> Also while you are cleaning that area if you or a helper hold a shop vac hose close to the area you are cleaning, that will help keep it from falling in.


A rubber vacuum cap stuffed into the sensor hole works well too.


----------



## EricD701 (Jan 19, 2007)

B&B;999007 said:


> A rubber vacuum cap stuffed into the sensor hole works well too.


This is true


----------



## RichG53 (Sep 16, 2008)

B&B what type of grease ???? Lithium ???? With a spray tube ..... OR ?????


----------



## B&B (Nov 4, 2006)

Any old chassis/wheel bearing type grease you have lying around is fine. You're only using it as an anti rust coating anyway. Being heavy based it lasts the longest.


----------



## QuadRacer041 (Sep 1, 2003)

Just wanted to let everyone know, I finally got around to clean the rust away from the front abs sensors now that the weather has gotten better out. All fixed, cleaned both left and right abs sensors, very easy to do and that fixed the problem. Thanks for the help.


----------



## cjwoz (Jan 7, 2008)

Clean the abs sensor and the back of the rotor that fixed my truck


QuadRacer041;997193 said:


> I have an 06 2500hd crew cab. Lately I've noticed that when I hit the brake the pedal it feels spongey right before the truck comes to a stop, real low wheel speed.What could that be? Air getting in the system somehow? I haven't had any service on the brakes done recently, I dont know how it could have started. Any ideas? I talked to a buddy of mine who is a mechanic at a dealership (not chevy though) and said that he thinks it could be an ABS sensor going bad. After he said that it kinda make sense because the action I get from the brake pedal when it happens feels like the abs is kickin in.
> Any info would be greatly appreciated.


----------

