Anti-Lock Brakes Help Help Help

Corvette Jabo · May 17, 2005

This is a question I posted about a year ago.

History: I own a 1995 K2500 light duty 3/4 ton truck. The truck has about 79K original miles, and never been hit or in any accident. I parked the truck in the garage for the winter in 2003. I pulled the truck out in spring of 2004 and now every time I come to a stop the Antilock Brakes kick in for the last 15 - 20 feet of each stop no matter if it is a hard or soft stop.

As of today: I changed the front brake pads on the truck this last weekend because there was very little left on the pads. I also bled the brake lines front and back.

The last time I posted some one mentioned that I should check the antilock sensors for dirt. I can see the wire harnes going to each of the front brakes. I do not see any sencors on the back to check.

1) For the fronts do I pull the calipers, rotor and dust shiled to get to the front sensor? When I find the front sensor what am I looking for?

2) Could it be the Antilock brakes unit just after the master cylinder? Man I hope not!

3) Has any one heard of a recall on something like this or a service documents on this?

Any help that you guys could provide would be well appreciated.

Thank You

Jabo

Bish · May 17, 2005

My guess is a dirty sensor. If I'm not mistaken, the sensor may be integrated into the hub on 2500's You may have to pull the hub. Rust around the sensor is common and should be cleaned up. Much easier on the 1500's as you can just blast with brake cleaner and you're good to go.

Corvette Jabo · May 17, 2005

My guess is a dirty sensor. If I'm not mistaken, the sensor may be integrated into the hub on 2500's You may have to pull the hub. Rust around the sensor is common and should be cleaned up. Much easier on the 1500's as you can just blast with brake cleaner and you're good to go.

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Thanks, I will start to rip it apart. I hope this does the trick!

Jabo

Corvette Jabo · May 19, 2005

OK, I took the hubs apart and removed the sensors and yes they did have grease on the heads of the sensors. I cleaned the sensors up and put the front end back together and it still does it. I looked at the speedo this time as the antilock enguaged and it was at about 14 MPH.

Looking for more help. Is there any way to test the sensors on the front? Are there sensors in the rear end also?

Jabo

Bish · May 19, 2005

OK, I took the hubs apart and removed the sensors and yes they did have grease on the heads of the sensors. I cleaned the sensors up and put the front end back together and it still does it. I looked at the speedo this time as the antilock enguaged and it was at about 14 MPH.

Looking for more help. Is there any way to test the sensors on the front? Are there sensors in the rear end also?

Jabo

<{POST_SNAPBACK}>

Did you clean up the toothed gear that the sensoe rides over? Grease in the teeth will caue the same symptom.

Also, not sure but I think you can put a meter on the sensor and spin the wheel to see if you are getting proper voltage. I believe it goes on and off depending on the position. I'd have to check my Helms manual to be sure on the testing.

You also could have a code stored even though the light did not go on. If you could pull a code it may help determine which wheel. Yes, there are sensors on the rear also. There may be one at the driveshaft and not at each axle in the back.

Good Luck.

bronyaur · May 19, 2005

I just went through this. Your wheel bearings are shot. Remove the hub, grab the inside, and see if there is any play at all. If there is movement, that's your answer.

After cleaning the ABS sensors, then replacing them at a total cost of over $250, I ended up replacing both hubs. I got them at Napa Auto Parts and they were about $220 each. It could be that only one side is bad and you only need to replace one, but I replaced both. Problem solved.