Jimbo_Slice
New Member
Working on a friend's bus, 09 International CE200, maxxforce 7, air brakes, we had a no-start issue that we fixed, turned out to be the IMS attached to the starter, but in the process of trying to figure out why it wouldn't start, we ended up replacing the air dryer cartridge and one of the brake chambers thinking it might be a parking brake interlock preventing it from starting. We also, while we were doing that, removed the stop arm, since this is a conversion, and the electronics for the doors, but it doesn't throw a code about the doors without them, so I don't think the doors are our problem with the brakes, it starts up fine.
Full 120 in both tanks, but the dash control valve for the parking brake (big yellow knob) doesn't get any pressure, no air noises, no tactical feedback. Brakes, as the title stated, don't release. Even started it up with the hoses disconnected and it still built up full 120psi in both tanks, no air going to the dash control valve.
Got a spn (I think those are the letters?) 3975 fmi5 code which, best I could figure out points to stop arm. I'm not 100% I found the right place to look up that code, but we did remove the stop arm and the light that comes on on the dash is an abs light, so I'm thinking maybe removing the stop arm tripped something that won't let air get to the dash control valve, and that's why the brakes won't release. I tried to disconnect the positive terminals from the batteries and jumper the wires that would have gone to the stop arm (there were 3 wires, I tried all possible jumper configurations, disconnecting battery and waiting 15m between) but zero change in the codes and no new codes, nothing. I'm running out of ideas and tired of bashing my head against the wall and I know we should have messed with this one thing at a time rather than fiddling with multiple things and needing to figure out which one broke it, but I honestly been working on cars my whole life and had no idea how busses worked when I started this whole journey and I walked into it with other people had already started pulling some of the stuff apart and I've tried to dig myself outta this and I think it's time to throw myself on the mercy of the court and seek some salvation. Anyone have any hints about what is going on with this parking brake?
Full 120 in both tanks, but the dash control valve for the parking brake (big yellow knob) doesn't get any pressure, no air noises, no tactical feedback. Brakes, as the title stated, don't release. Even started it up with the hoses disconnected and it still built up full 120psi in both tanks, no air going to the dash control valve.
Got a spn (I think those are the letters?) 3975 fmi5 code which, best I could figure out points to stop arm. I'm not 100% I found the right place to look up that code, but we did remove the stop arm and the light that comes on on the dash is an abs light, so I'm thinking maybe removing the stop arm tripped something that won't let air get to the dash control valve, and that's why the brakes won't release. I tried to disconnect the positive terminals from the batteries and jumper the wires that would have gone to the stop arm (there were 3 wires, I tried all possible jumper configurations, disconnecting battery and waiting 15m between) but zero change in the codes and no new codes, nothing. I'm running out of ideas and tired of bashing my head against the wall and I know we should have messed with this one thing at a time rather than fiddling with multiple things and needing to figure out which one broke it, but I honestly been working on cars my whole life and had no idea how busses worked when I started this whole journey and I walked into it with other people had already started pulling some of the stuff apart and I've tried to dig myself outta this and I think it's time to throw myself on the mercy of the court and seek some salvation. Anyone have any hints about what is going on with this parking brake?