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larry78
User
Aug 14, 2010, 5:50 PM
Post #1 of 4
(11302 views)
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2005 Silverado ABS
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2005 Silverado. 59,000 miles. I do not know if pads / rotors have ever been replaced. Bought truck used at 48K-miles. Light use since.
My ABS kicks in when not needed. As I approach a stop slowly, especially when going down hill, my ABS kicks in just when you want full braking power....as in applying more braking pressure just to come to a full stop. I suspect a bad wheel sensor. Good thought or something else? Have not had brakes inspected. I suspect I need at least front pads and rotors. Some signs of warped rotors.
Any ideas welcome!
Thanks,
Larry
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Hammer Time
Ultimate Carjunky
/ Moderator
Aug 14, 2010, 6:00 PM
Post #2 of 4
(11299 views)
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Re: 2005 Silverado ABS
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There is actually a TSB on that problem for that truck.
Here it is
TECHNICAL
Bulletin No.: 03-05-25-007D
Date: May 01, 2009
Subject: Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface) Models:
2002-2006 Cadillac Escalade, Escalade EXT
2003-2006 Cadillac Escalade ESV
1999-2006 Chevrolet Silverado
2001-2006 Chevrolet Suburban, Tahoe
2002-2006 Chevrolet Avalanche
2003-2006 Chevrolet Express
2007 Chevrolet Silverado Classic
1999-2006 GMC Sierra
2001-2006 GMC Yukon, Yukon Denali, Yukon XL, Yukon Denali XL
2003-2006 GMC Savana
2007 GMC Sierra Classic
2003-2006 HUMMER H2 Supercede:This bulletin is being revised to add the 2007 Silverado/Sierra Classic models. Please discard Corporate Bulletin Number 03-05-25-007C (Section 05 - Brakes).
Condition
Some customers may comment on ABS activation at low speeds, usually below 8 km/h (5 mph). Upon investigation, the technician will find no DTCs set.
Cause
The cause of this condition may be an increased air gap between the wheel speed sensor and the hub reluctor ring due to rust and debris built up on the sensor mounting surface.
Correction
Measure AC voltage and clean the wheel speed sensor mounting surfaces. 1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in the General Information sub-section of the Service Manual. 2. Disconnect both the front wheel speed sensor connectors at the frame and harness. 3. Place a Digital Volt Meter (DVM) across the terminals of each wheel speed sensor connector. 4. Rotate the wheel clockwise approximately one revolution per second. The minimum reading should be at least 350 ACmV's. If the reading is less than 350 ACmV's, remove the wheel speed sensor. Refer to the applicable Wheel Speed Sensor Replacement procedure in the ABS sub-section of the Service Manual. 5. Plug the wheel speed sensor bore in order to prevent debris from falling into the hub during service. 6. Clean the wheel speed sensor mounting surface using a wire brush, sand paper, emery cloth, scotch brite, or other suitable material. Be sure to thoroughly clean the wheel speed sensor surface. There should be no rust or corrosion. 7. Check the sensor head to determine if it has been warped/distorted due to the corrosion build up or other causes. Check the mounting surface on the sensor head for flatness by placing it on the edge of a metal machinists scale or other suitable straight edge to measure the flatness. Check the sensor for flatness in multiple (minimum 3) positions/directions. If the sensor head is distorted, replace the sensor. 8. Apply (spray) two thin coats of the specified rust penetrating lubricant (corrosion inhibitor) to the complete sensor mounting surface on the bearing hub. Allow to dry for 3-5 minutes between coats. Use ONLY Rust Penetrating Lubricant, P/N 89022217 (in Canada, P/N 89022218). 9. When the corrosion inhibitor is dry to the touch (about 10 minutes), apply a thin layer of bearing grease to the hub surface and sensor O-ring prior to sensor installation. Use ONLY Wheel Bearing Lubricant, P/N 01051344 (in Canada, P/N 993037). 10. Install either the original sensor or a new one in the hub. Ensure that the sensor is seated flush against the hub. Refer to the applicable wheel speed sensor Replacement procedure in the ABS sub-section of the Service Manual. 11. Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel. The voltage should now read at least 350 ACmV's.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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larry78
User
Aug 17, 2010, 7:25 PM
Post #3 of 4
(11288 views)
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Re: 2005 Silverado ABS
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 Thanks Hammer. Won't fix this one myself but now I know what to ask for.
Best regards,
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larry78
User
Sep 12, 2010, 12:19 PM
Post #4 of 4
(11241 views)
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Re: 2005 Silverado ABS
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Okay so I had a dealer check out the brakes and mentioned the service bulletin. They were aware of the service bulletin and I have seen since that there was also a recall for the corrosion issue. I also had the brakes and rotors replaced since they needed it and some other routine service.
The dealer said the wheel sensors needed to be replaced and I okayed that repair.
When I first picked up the vehicle (on Saturday) all seemed well and I went to the grocery store and then home. On the way home I noticed an intermittent, rotating grinding sound, like something metal rubbing against the brake rotor. The noise seemed to happen most often when I was turning left at low speed. Most of the time there was no noise. I decided to pull the front wheels off to see if I could spot the problem.
The first thing I noticed was that the lug nuts were not much more than finger tight. I did not see any signs of metal rubbing metal and all the new parts that were supposed to be there are there.
I put the wheels back on and tightend the lug nuts up and took the truck for a drive. I have not heard the noise since.
So my question is whether the loose lug nuts could be the source of the noise.
Thanks for any help you can provide!
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