2004 Chevy Silverado 4WD, 4.8 L, ext cab (393,000 mi) My abs light was coming on. Occasionally at low speed the abs would engage and make a chatter to the brake pedal before stopping, but not all the time. I checked the code and it was the front left abs speed sensor. Checking around, it seems like a common problem. Fairly cheap part, easy to replace, so I did that yesterday. No light, but now EVERY time I brake at low speed (exactly 10 mph) it does the chatter in the pedal. So, either I didn't fix it with that, or I did something wrong when I installed it. I looked up a few more things and found this service bulletin: Spoiler: Bulletin 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. I'm not sure about the bold part in # 8. I have a few questions based on that. I don't think the sensor is bad or needs cleaning since it's new - although, I could've gotten some grime on it. But, what is the bearing hub? Is that the same as the hub? When I pulled out the old sensor, I could see teeth when I spun hub. I'm not sure what I'm supposed to be spraying lubricant on. Is it okay to spray the crap out of everything (but the sensor) with brake cleaner, let it dry and then spray the lube? Because, that shit is dirty and greasy, and it was tricky feeding that sensor in and out to the hole, through the little gap in the flare by the hub, without getting dirt and grease on stuff.
I'm not a mechanic, nor do I play one on TV, but if I had to guess, I would say that they just want to eb sure that the mounting surface between the sensor and the hub is clean and to be treated to inhibit the formation of rust as it could affect the readings from the sensor over time. I don't think it has anything to do with bearings or anything... just a bit of anti-rust protection between the two surfaces where the sensor mounts.
Did a bunch of these at the dealer, you just replaced the sensor correct? Left the old hub in the truck and just removed the wiring and sensor? If so you need to pull the sensor back out and clean the mounting surface of the hub with some Emory cloth or something simliar, reinstall the sensor and retest it. Surface needs to be clean and flat down to shiny metal, doesn’t take much for these to get screwy. If it fails again you’ll need to repace the whole hub as an assembly, most of them come with a new sensor installed.
Yes. OEM part not cheaper knockoff. The mounting surface, like where the sensor and 5mm screw attaches to the hub? I did not clean that as well as I could have, and there were two spacers there that also weren't shiny. One was plain metal and the other was brass or something. Not sure why. But, yeah, I can do that. Well, crap, that goes from being about $40 to about $400. I pulled the abs fuse for the time being, because it was annoying. I've put all 393k miles on this truck over the last 15 years and I've never once braked in a way that the abs needed to engage anyway.
Brass is not magnetic, it is conductive, and it resists corrosion. You'll find that a bunch of sensors use brass. (At least a ton of them on our race cars did).
Yes that’s the surface that needs to be cleaned. More than likely that’ll be all it needs if you can get it clean flat and shiny.
Gotcha. I knew that about brass, but I really meant why one was brass and the other steel. I guess the against-the-hub piece is brass for corrosion and conduction, and the against-the-sensor piece is for strength? Plus, not doing both in brass probably saves $0.00003 per vehicle. I just find a lot of that weird, and that all the different segments do their design and building without coordinating particularly well. I've enjoyed learning a lot by working on my truck. For the most part, this Chevy is MUCH better assembled and constructed than other vehicles I've worked on. But, the lack of standardization drives me crazy. The sensor line had three different types of clips holding it in place. The caliper bracket is two 3/4" bolts, but the caliper is two T55 Torx. They could've easily been the same thing. I've found similar things . . . take apart this, it's 8mm, next thing is 5mm Allen, then, Phillips, then back to 8mm. Constantly changing tools on the same project for things that could be the same size drives me bonkers.
I did my first ghetto home fix this weekend, thought you guys would like a laugh. I'm usually pretty precise with car repairs because my tools and expertise are both limited, so doing something a second time is a big pain in my ass. Years ago, a shop fixed a leak by cutting off a section and welding in a new one. A couple weeks ago, that piece broke, leaving jagged rusty metal spikes and holes on either side of the break. The upstream bolts are rusted in place, so I can't get the entire section off to replace or repair. My tools are currently limited (i.e. no angle grinders, welders, etc.), and it's at a bend, so I can't easily cut out a chunk and replace it. The previous welding job and the bend make it difficult to clamp anything on the outside. And since it's 110 with the heat index, my interest in spending significant amounts of time working on this (e.g. with a hacksaw) is nil. Solution? Took a soup can, cut the bottom off, rolled it into a tube and clamped with a hose clamp. Liberally applied high heat epoxy to the insides of both pipe sections. Slid the can into the exhaust pipe and rigged up some clamps and zip ties to pull the two sections together. Released the hose clamp to let the soup can unfurl and give some support to the exhaust pipe. Wrap the whole thing in fiberglass tape, then again in metal tape to hold the fiberglass in place, and run the car for an hour to cure it. I have no idea if this will pass inspection next year, but for $8 worth of materials and 20 minutes of time, I don't care. Need to get under there tonight and pull the metal tape off.
A+ Shade Tree repair job right there. There's a good reason why you keep a bunch of old coffee cans around the shop.
I've got a question....what is everyone's experience with 2000-2010 Lincolns? I'm trying to be reasonable with buying a used vehicle (Disregard my babbling about the Z31 over the weekend). Older Lincolns can be had pretty cheap in exceptional condition. My thought is they were generally bought by older, affluent folks who took care of the cars. There was a good chance they were initially bought as a status symbol, but an 8-12 year old luxury car is not a status symbol, therefore they do depreciate quickly, and chances are not many of them have been driven hard. I'm also aware that a 15 year old car that cost $40K new is still a $40K car when it comes time to replace parts. I'm wondering if many of the parts on a Lincoln are just Ford parts? Does anyone have any experience with these Lincolns? My truck is dying by degrees, the water pump is now knocking so loud it sounds like a diesel. I'm going to have to make a decision in the next few days.
What kind of Lincoln? If it's a Town car or a Navigator, I'd say go for it, because those are built on solid platforms. (Of course those are the same thing as a Grand Marquis and an Expedition, respectively) I'd stay away from the Lincoln LS because of parts availability and some weird designs Ford was playing around with at the time.
I had a Town car years ago when I was doing real estate and I loathed that thing. It sucked beyond sucking. It wallowed like a ship in heavy swells on a bumpy road. I've got another deal in the works and this one should be right up your alley... '96 Z28, LT1, 6 speed, right at 100K, 2nd owner, all stock. At least being box stock tells me it *probably* hasn't had the piss beat out of it. Body is straight, interior is clean (It's velour, not leather which is a minus to me.) The downside is it's in OR which means either I fly up there and drive an unfamiliar car 1000+ miles or pay (I'm guessing $1000) to have it shipped here. I could pick it up for $2500-3000, plus shipping. From what I remember from years ago is the biggest problem with 4th gen Camaros was the auto tranny, which since this one is a 6 speed is moot point. Is there anything expensive that starts failing on these cars at around 100K? What are some of the major failing points? Thanks for your input, I really do appreciate it.
That's really not a bad idea, but this guy lives in Bum Fuck, Oregon and is a car guy which means he probably knows every local mechanic. Maybe I've been lucky, but I haven't had any problems with any car I've bought over the internet. That being said, we're in the e-mail stage right now, I'll certainly talk to the guy if it gets serious and if I detect the slightest bit of bullshit on his part I'll move on to something else. EDIT: Holy shit! I didn't notice before, but this thing has manual windows and locks! How many 4th gen Z28's had that? I would've thought that power windows were standard equipment.