robp823 Posted February 12, 2009 Share Posted February 12, 2009 I have an 04 f-650 with merritor wabco abs system. The abs light wouldnt go out so i contacted merritors tech line and they said to blink the codes out of it since my dealer doesnt have the software to diag this. So what i blinked out was there is no codes, go figure.So merritor suggested adjusting the abs sensors so i did that by pushing in all the sensors as close to the tone rings as possible and i guess they self adjust.When i did i then took for a long test drive and the light stayed off so i returned to customer.The next day they said the light came back on and there now bringing the truck back and im stumped.Any help always appreciated Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 12, 2009 Share Posted February 12, 2009 Do you have the MD truck software bundle and the IC3 or IC4 comm cable? You can download the software for free from FMC Dealer. If you think pushing in the wheel sensors had an effect you might want to check your wheel bearings for excessive play and in inspect the tone rings for corrosion. The last F650 I had in for ABS problems was caused by excessive rust and I mean extreme rust causing too large of an air gap. I also have some diag sheets from Merritor I can look at when I get to work. Those Merritor Wabco ABS systems are fairly trouble free from my experience and pretty much any time I have a run in with one it is a sensor issue, beit a failed sensor, wheel sensor gap as mentioned or a sensor wire has been damaged. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted February 12, 2009 Share Posted February 12, 2009 problems was caused by excessive rust and I mean extreme rust causing too large of an air gap. +1 on this. 95% of the problems with this ABS system are in the wheel end with bad barrel clips, rotted reluctors and loose wheel bearings most common. It should have barrel clips holding the sensors in. They lose their tension with time and heat, allowing the sensor to walk out, decreasing the output voltage and setting a WSS code. Push the sensors in, there should not be any appreciable travel when pushed. If they move, the barrel clips are junk or the wheel bearings are too loose. It's a good idea to change the barrel clips as a maintenance item. Then pull the sensors out and inspect the tips for excessive wear and examine the reluctor at the same time for rust. Some wear is normal but if copper shows they're bad. They might have a steel pin in the center of the sensor showing, and that's OK. I'm not sure if your truck will have reluctors pressed onto the hubs, or cast into the rotor. If it's cast into the rotor, it's not unusual to get 4 rotors to fix this problem in the rust belt when the reluctors are rotted badly. If they're pressed onto the hubs, it's common for a previous "tech" to have bent them by installing the sensors with a hammer. Use only hand effort to push the sensor in. I usually use a standard screwdriver pressed against the base of the sensor and gently smack the bottom of the screwdriver with my hand to seat the sensor. Wheel bearings have to be on the snug side of the adjustment spec as a few thou of end play will result in ABS codes if all of the parts are good. Occasionally you will have a rotted harness or wire, also. If you suspect a wiring problem or bad sensor disconnect the processor and check resistance with a DVOM through the complete WSS circuit. If you have no access to software for diagnostics, unplug the processor and check resistance of each sensor through the complete harness, rather than just the WSS pigtail alone. Compare resistance of all four, I'm thinking 500 to 2000 (2K) ohms might be correct. Then switch your DVOM to ACV and have a stocky buddy spin each wheel and check for ACV from each sensor. Normally you will see .8vac to 1.2vac at 30rpm at the wheel end. The book says .2vac minimum but I'd be concerned if I saw this low. Pay attention not only to the voltage, but also how stable the output is- there should be no more than a couple tenths of variation as the wheel is spun by hand. If it varies by a half a volt, the reluctor is not running true due to rot, damage, loose bearing, etc. Compare notes with all four using this diagnostics and you'll find your bad boy(s). Having the software makes things easier, but manual diagnostics works very well. Good Luck! Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 12, 2009 Share Posted February 12, 2009 Good show Bruce! The reluctors are cast to the rotors if I recall correctly... maybe Mr Dupont remembers? Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted February 12, 2009 Share Posted February 12, 2009 Quote: It should have barrel clips holding the sensors in If you are or have a Freightliner LLC dealer nearby the part number for the barrel clips is TDA/R955459 should be about $5.00 or they should come with the sensors of which I believe there is about 6 different numbers for the sensor. They are model specific depending on the length and what connector is on it. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted February 13, 2009 Share Posted February 13, 2009 There are several different PN barrel clips made by Bendix, Wabco, and TRW/Kelsey Hayes that look ALMOST alike and almost interchange but are specific to a WSS and it's composition.(stainless steel sheath, plastic sheath, etc) The wrong clips may install and function correctly, but I'd beware of not using the proper PN clip. A page from my book showing some Bendix sensors that will not interchange with TRW sensors that look alike: PS The "clips" need a special grease to keep them from corroding. High temp brake grease might work. Good Luck! Quote Link to comment Share on other sites More sharing options...
eastendpowerstroke Posted February 13, 2009 Share Posted February 13, 2009 Bruce has covered everything there is to cover (as usual) so I can't add much except. Any time I get an ABS light on an F-650 I developed a quick test I like to use, I road test to verify the light but I take a little hammer with me. when I turn around I'll stop,get out and use my little hammer to tap all 4 of the sensors in and drive back to the shop. If the light goes out I'll check check codes for the axle I need to check bearings and tone rings on. If it doesn't go out then it more than likely has a sensor bad. I have seen many that the sensor was just pushed out but had no discernible bearing play or "excessive" tone ring rust problems, my only explanation is maybe a hunk of rust,or a stone just knocked it back a little. Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted February 13, 2009 Share Posted February 13, 2009 Quote: I have an 04 f-650 with merritor wabco abs system As stated the TDA/R955459 are for the Meritor Wabco ABS. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted February 13, 2009 Share Posted February 13, 2009 I have seen many that the sensor was just pushed out but had no discernible bearing play or "excessive" tone ring rust problems, my only explanation is maybe a hunk of rust,or a stone just knocked it back a little. I disagree with this statement. I'll respectfully state that I have had many students tell me horror stories about taking the truck to a dealer (sometimes repeatedly) for an ABS light, having the tech push the sensors in, clear codes, and return the truck to the owner, only to have the light come back on quite soon. In the interest of keeping a customer happy: If the sensor works loose on a new truck with no miles, it's because the wheel bearing(s) are just a shade loose. (BTDTGTTS, many times) If the sensor works loose on an older truck with higher miles, it's because the barrel clips have lost their tension, or a combination of problems. (BTDTGTTS, many times) Sensors don't work loose for no reason. Especially with IH trucks (which use this same Wabco system and a very similar Bendix ABS system) this is a pattern failure and a pattern assache for customers. Being that all major MD/HD truck mfr's use the same axle/brake suppliers, I'd go out on a limb to say this must be a pattern failure across most truck mfr lines. I'm not sure what the real problem is- political, where the tech isn't paid properly for his diag, being too busy/shorthanded in the service dept and needing to "get it done", laziness on the tech's part, lack of experience, or unwillingness to be thorough in doing the repair. I'll respectfully disagree with you in a very strong way- WSS don't walk out because of a stone hit, and if the rust is bad enough to push the sensor out, the barrel clip has seen better days, in addition to wanting me to ask what else is borderline in there after enough rust has built up to "push a sensor back". I've seen too many times where the customer is tired of taking the truck back to the dealer for the same old "light" and either lives with it or takes it to another shop. When I had my shop, we did plenty of "warranty" work at full boat. This means the cust was so fed up with their local dealer's service dept that they would rather pay me full retail than get the repair for free at their selling dealer. I sold a major training account because of this several years ago. During a sales presentation, a fleet manager told me this exact story of repeat WSS codes and techs who pushed the sensors in and cleared the DTCs on new trucks. I told him exactly what I said in my first post on how to have his techs diag it themselves in 30 minutes or less. It turned out to be loose wheel bearings- not loose enough to feel with a prybar, but tightening the nut one flat fixed a bunch of his trucks with the same problem. He's been a dedicated training customer for quite a few years now. I'm trying to make a point and be respectful at the same time. Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted February 13, 2009 Share Posted February 13, 2009 This may help with diag. http://www.meritorwabco.com/literature/hydraulicabs.asp https://www.fulfillmentonline.net/Distribution/Order/ViewPreview.asp?ID=2889 https://www.fulfillmentonline.net/Distribution/Order/ViewPreview.asp?ID=2685 Quote Link to comment Share on other sites More sharing options...
robp823 Posted February 15, 2009 Author Share Posted February 15, 2009 wow this all was awsome info thanks so much guys once again saved my ass! Quote Link to comment Share on other sites More sharing options...
eastendpowerstroke Posted February 15, 2009 Share Posted February 15, 2009 Quote: I disagree with this statement. As is your right to do. I'm a big boy my feelings won't be hurt. Quote: I'm not sure what the real problem is- political, where the tech isn't paid properly for his diag, being too busy/shorthanded in the service dept and needing to "get it done", laziness on the tech's part, lack of experience, or unwillingness to be thorough in doing the repair. Laziness or unwillingness is NOT an issue, I will gladly admit to "inexperience" as I was thrown into MD trucks by my dealership with no formal MD/HD truck training or equipment.Any thing I've learned about MD trucks have been on my own. Quote: WSS don't walk out because of a stone hit, and if the rust is bad enough to push the sensor out, the barrel clip has seen better days, I didn't realize the clips were such a problem. I have spent the time and effort many times diagnosing a ABS light and after following the Diag for the wss code and checking/adjusting the wheel bearings per the WSM and finding nothing wrong,other than the sensor gap incorrect I'll be sure to check the clips more closely in the future.FWIW I have tried to take the training offered by Ford for Commercial brakes, but the required classroom training hasn't ever been offered in any Ford training center anywhere I know of. I've had a course request in for it since June 20,2005.Maybe Ford could Hire you to teach it. other than The New Model course's for the LCF and F650-750 Ford doesn't offer much as far as training for MD trucks. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 15, 2009 Share Posted February 15, 2009 other than The New Model course's for the LCF and F650-750 Ford doesn't offer much as far as training for MD trucks. Interesting observation and you are correct. If I think about this for a moment, what could Ford offer? I think to be worthwhile any classroom course would have to offer general systems and component training. The basic trucks are fairly simple and straight forward... its the major sub-systems like the engines, transmissions, air brakes and ABS that present the challenge in that they are NOT Ford parts and systems and therefore support for them is limited at best, usually non existent. I personally learned that hard lesson first hand in dealing with Caterpillar and Allison. I suppose when it comes to the F650-750 a general familiarization course similar to the LCF launch class would be nice, but the LCF, despite being a Blue Diamond truck, is assembled from familiar Ford and International parts. A F650-750 has major parts content from Cat, Cummins, Navistar, Allison, Dana/Spicer, Wabco, Bendix... Quote Link to comment Share on other sites More sharing options...
eastendpowerstroke Posted February 17, 2009 Share Posted February 17, 2009 Now that Cat isn't in the on HWY truck engine biz anymore and there is NO Navistar engine currently available for the 650-750 blue diamond trucks that leaves only Cummins. The way I see it,thats a pretty short list of engine options Even if we get a new Navistar engine option it still makes only TWO engines. It should be real easy for Ford to get at least basic diag info to determine if it's a problem for the engine maker or an OEM problem and pass it on to the guys that gota fix em' Quote: Wabco, Bendix Brakes, Ford has a certification for that, both Web based course's and "classroom" course's for Commercial brakes, Air Brakes - Theory and Operation (58S01W0), Service and Diagnosis (58S02W0) and Hydraulic Brakes - Theory and Operations (58S03W0) .But the classroom part (58S01T0,58S02TO) doesn't exist! What good is offering certification for something and never holding class???? Quote: Dana/Spicer Manual trans and axle service info is covered in the WSM and is straight forward, however most internal manual trans parts weren't available from Ford last I looked. I had a Spicer 7 spd that needed syncros was told to get a reman unit? OK! Quote: Allison UUUGGG!!! Dealing with Atlantic D.D.A is like jamming a sharp stick into your eye Quote Link to comment Share on other sites More sharing options...
Damon Posted February 18, 2009 Share Posted February 18, 2009 UUUGGG!!! Dealing with Atlantic D.D.A is like jamming a sharp stick into your eye Oh, man. You noticed this too? Quote Link to comment Share on other sites More sharing options...
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