Don't know if anyone has experienced this yet but, one of our newer feed trucks 2020 Pete 567,straight truck, disc brakes all around with 80k miles has developed abs issues that were a little tough to diagnose..I'll spare all the details of chasing my tail around and racking my brain,but after much investigation found the new tone rings are not pressed on and are a 1/4 inch bolt on piece of crap, secured by 5 T27 torx screws and get rust jacked enough to push the sensors out just enough in between the fasteners to cause a code to appear, and once you get a code the cruise or engine speed up doesn't work, because newer trucks don't have speedo sensors on the trans tail shaft anymore and we kinda need the speed up for the pto pump..Now unless you pull the wheels there is no way to even see the tone ring, at least on the drives and conveniently the sensors are accessible from inside the spider so you put a new sensor in, clear the codes and it's good to go for a couple of days...The Pete rep./ salesman that comes to our shop on a weekly basis says they haven't had this problem before but it took us two weeks to get the backordered tone rings hmmmm..good news though, the T27 screws are stainless so they're easy to get out,after you remove the caliper and heavy ass hub with the rotor attached and replace the wheel seal...Bad news is the same steel piece of crap tone ring is $195 and is going to fail again..We tried slathering copper neverseize in between the hub and the new ring fingers crossed...Well that's enough of my rant, but it's coming to a shop near you especially if you live in the salt/ rust zone...Good Luck...Stinky
I take it this as a feed truck is receives little wash time, out in feed lots or down slightly improved gravel roads or on gravel lots after a winter of salt spreader covered secondary roads. LIBERAL Washings as return to the yard will aid in limiting rust jacking but will not stop it. To eliminate the issue will require specialized spec order of the machines to rough CORROSIVE service possibly even back to Drum Braking, likely need to follow the trash service equipment protocols as they as well end up in seriously corrosive environments. You were likely sold as to benefits of Disc Air Brakes by sales staff for maintenance or adjustment mechanisms but without the forethought of the corrosive environment as our own State Hiways Department failed to do where those machines end up literally corroded away in less than 5 years. Steel to Steel does not create a Battery effect as does Steel to Aluminum where is are seeing rust building on a less than 2 year old machine are definitely awash in a corrosion environment.
The problem with getting the tone rings isn't that there is a major issue with that certain tone ring or there is a run on those particular parts. Freightliner just shut down their assembly/new truck manufacturing line for two weeks to let the outside vendors catch up. They were diverting replacement parts from the DC's for manufacturing and that caused a shortage. PacCar has set back new truck delivery dates as much as 6 months because of the same issues. Cummins is way behind on complete engines and replacement parts.
You are spot on about the conditions these trucks live in and these guys wash their trucks all the time..the outside shiny parts that is..the chassis gets very little attention and the bodies are fixed so its damn near impossible to powerwash under there.The big trucks with trailers are a little more open so they're not as bad but still hold a lot of grime..As far as the wheel hubs they are steel with a steel ring,but I think the 1/4 inch thickness of the ring and fastener spacing is the culprit..I'm also with you with the drum brakes, lots easier to maintain and see brake wear..