Week of 9-23, I thought I'd quickly pull out all the interior panels even though I would be out of town for 2-3 days, here's where I learn 1 single thing that affected nearly every part of the demolition phase of the bus: all panels are epoxied together!
The Beeping
But let's back up to the start, I only had a half-day monday, so I was going to take a load of trash from the seats to the dump and start on the ceiling. While waiting on my uncle with the pickup truck to arrive, I decided to see if the 8-ways were still operable as I wanted to make sure they were disabled since I think that's a law or something. I turn the bus to ACC and try the warning light switch, sure enough the 8-ways light up. I also heard a new beep I hadn't heard before, weird. I play with the door, learning how the warning lights work, then I turn everything off and turn the bus key back to the off position. Immediately I heard a very loud and frantic beeping from inside, just as I start to look that I have everything switched off the freaking HORN starts going off like a car alarm! I turn the bus back to ACC and the beeping stopped, phew.
Now, to figure out what's going on, I try just turning the bus off again, nope it's still beeping, back to ACC for silence. I had already removed the red button at the back, so I wire it back up...press it, still beeped when turning the bus off. I check all of my emergency door switches, reinstall the rear door switch (I had unplugged so the reverse lights wouldn't remain on while working on the bus), didn't help, still beeps like crazy when turning it off.
I realize I need to google what the heck that red button was that I removed, I figured it was a kid check system to force the driver to walk to the back at the end of their shift, and I was sure by now that it was the cause of the beeping, but needed to understand EXACTLY how it worked if I was going to understand how to shut it up.
I found the name of it, Child Check Mate EP1. I found the installation and user manual. I found out that I need to press and hold the button for 2-3 seconds to disarm it, and it would give a confirmation beep when doing so. I wired the button back up, held it, listened for the disarm confirmation beep....nothing. The button was busted it seemed. I tried shorting the wires directly, hoping it was a dumb switch....nothing.
The manual showed a picture of the controller, so I knew I needed to find and remove it. So I start tearing into the left console, removing the switch panel, and thankfully it wasn't buried too deep. A single plug to remove, and silence
I realized that it was turning on the warning lights that armed the system, that's what that weird beep I heard was.
I finished by fully disconnecting all the wires for that module so I wouldn't have unused wires laying around, and could get back to the plan now that my sudden frantic hunt was over.
The Ceiling
I was thankful that the ceiling panels were screwed in, I bought a bunch of those square bits (because they deteriorate rather quickly) and with my mini-impact it was making quick work of the screws, and having the right bits greatly minimized the chance of screws stripping out.
I start from the back of course, since the rear panel isn't trapped under the others...but as I've removed most of the screws, I'm starting to wonder why the panel isn't sagging down.
Eventually I have all the screws out and the panel isn't budging...wth.
Turns out, as you already know by now, the panels are glued in with a very hard epoxy around all 4 sides.
After trying to pry using various tools, I finally found that using vice grips to roll and peel it back along the edge was working...slow, but working:
Well, I quickly figured out I wasn't getting the ceiling done today. I basically had time to remove all the screws, then pry off just a total of 3 panels.
Here's a timelapse + edit of the peeling so you can feel the struggle:
https://photos.app.goo.gl/ruJCGQE8UHtgftKK8
I'm sure you can find the parts where I had to drill out a couple of screws
I had to head to TN for the night, came back the next afternoon to tackle the rest of the ceiling. I definitely got faster at it, but it still sucked. I guess it made it all the more rewarding to see it finished:
Turns out that some buses have the insulation glued in, so I at least was feeling lucky that the insulation came out rather cleanly.
The Batteries
I had a bit more time that day so I decided to see if I can get any data off the CAN bus of the batteries. I ordered a CANable stick from amazon the weekend prior and was excited to use it. After not much trouble I got it working, and it was very exciting to see the messages streaming in from the battery.
I found the DBC that defines the messages and got it decoded thanks to the cantools python library, and while it's a little hard to see, this picture shows the laptop streaming all kinds of juicy data from the BMS, cell voltages, temps, SOC, current, states, error states, etc.
Sadly, the dead batteries were only sending a single message at 1hz, and I didn't have the definition for that message, so I still have no idea why they won't turn on, I have 2 more tricks I can try, but I'll have to save that for a later date.
The Heater
I did have a bit more time that day still, so I started removing the trim over the rear heater hoses...and found that most of the screws just instantly broke loose, turns out they were breaking off. Once I lifted the trim and the screws lifted out with it, I could see why:
Those were a few of the screws, the one on the left is for reference, they are all the same size screws!
I found it interesting that they were rusted like that, but didn't think much more about it, other than it was along the edge where the heater hoses were, so I figured there was a coolant leak at some point.
The next day, 9-25, I also only had a half-day before heading to visit some family a couple hours away, so I decided to just focus on removing the rear heater.
That went surprisingly well. There were ball valves under the hood that isolated the heater cores from the main coolant circuit, they were a bit stiff but I managed to close them. I used a couple of vice grips to isolate the front heater core from the rear as they were both on the same side of the ball valves, then found a spot beneath the side door steps where the hoses were attached with a coupling. I figured I could disconnect at the coupling, then use a short length of the old hose with a kink to loop off between the couplings, the kink to create some back pressure so it wouldn't all bypass the front core (they were plumbed in parallel).
I managed to spill very little because by disconnecting under the bus first, I could have the bucket underneath the coupling where I disconnected it, and being the lowest spot, I could drain most of the loop. After disconnecting them, I left those ends in the bucket and went up top to disconnect the hose at the heather itself. I blew into them to push the rest of the coolant out into the bucket, then was able to disconnect the bulkhead fittings in the floor and remove everything without much mess.
The Rust
Fast forward to Friday, as the rest of Wed and all of Thurs I was visiting family. Being near Western NC the weather was obviously pretty bad as the hurricane was double-digit miles from us. I drove to the bus first thing in the morning, literally getting hit by falling branches along the way, because 1: I wanted to work on the bus, the power was out so nothing better to do, and 2: where my bus is located was the safest place my car could be as there were no trees nearby to fall, and I could park it in the lee of the bus to shield it from other flying debris.
I started removing the rear interior wall panel. Surprise surprise, it was also epoxied on
Being a more complex shape than the flat ceiling panels, it was definitely a lot harder to pry it off, but eventually got there. But I needed a break from epoxy, and those rusty screws have been on my mind as now that I'm removing more floor trim, I'm finding more rusted screws, ones that aren't near the heater hoses at that.
Another thing I noticed, the floor near the entrance (at the top of the stairs) was sunken, it wasn't level. I figured I should remove the center runner trim and see what the heck is going on underneath.
Many more screws breaking off when removing the center runner trim, at least I didn't have to drill them out, as the heads were just snapping off. I knew I'd have to grind the shafts off later as they'd definitely be sticking up through the subfloor.
And, well, poo...
One of the reasons I picked this bus is because there was not a spot of rust underneath...so I was devastated to see the floor completely rotted out from the top.
The plywood was still wet, at least what was left of it.
I was done for the day, no time or willpower to do any more work.
I went home, laid down and started scrolling r/skoolies for rust posts, and felt a little better to find out that this is pretty common, and my floor still seemed better than some have found underneath.
The Mechanic
...was me pretending to be a diesel mechanic on Saturday 9-28. The power was still out, so decide to go back out to the bus and see what I can do about a few problems with the bus itself.
First off, the heater constantly blew hot air, which sucked as it was already hot when driving it home the week before, it seemed the mixer door was broken.
I take apart the dash to find it's a fully electronic unit, I'm ok with that, let's see what's going on.
When turning the hot/cold knob, the mixer servo just turns for 1 sec, stops for 1 sec, then repeats about 4 times before giving up. I pull up the frieghtliner m2 troubleshooting manual and find the hvac section, it had a nice description of the the unit and how it worked. Turns out there's a potentiometer in the mixer servo to send a feedback signal to the controller...it seemed it didn't detect it was moving. There was a troubleshooting guide on which pins to read and what voltages to look for to indicate where the problem is. I trace it down to the pot isn't sending back the right voltages. I take it apart, clean it, still no luck. I turn it by hand with it apart while measuring the voltage, and find out that there is only about a 1/4 turn of travel where the voltage changes from 0-4v as it's supposed to. Nice, the pot is good, it was just in the wrong spot. It seemed the blend flap itself was going past the hard end stops. Or maybe it was the fact that the servo itself wasn't mounted properly to the blend flap (in fact, that's what it was).
I take apart the hvac further, fortunately it's a non-AC unit so just removing the filter door provides easy access to see the blend flaps. I learn there's 2 flaps, clearly supposed to be connected internally by a rod of some sort...but that rod is missing, and the flaps were both screwed to lock them into the hot position!!
I remove the screws, use some coat-hanger wire to create a new rod connecting them, now they moved correctly in sync with each other. And once I remounted the servo, it worked perfectly :biggrin:
https://photos.app.goo.gl/DqJoPt6mWHoELkiJ7
So it seemed that rod broke, the tech just screwed it to the hot position because commercial vehicles legally need the defroster to work, and left the servo to free-spin by not attaching it all the way.
Feeling confident having fixed that, I moved on to the engine codes. First one to try to tackle: barometric pressure sensor invalid data. Freightliner dealer said it's usually a loose connection, to clean the contacts before replacing the sensor.
I start looking for the sensor. The diagram I found showed it was behind the main engine ECU (MCM). I wasn't about to remove the MCM as it's plumbed into the diesel supply as a heat sink to keep it cool (I've heard of water cooling electronics, but diesel cooling is a new one to me!).
But still, even looking behind the MCM, I see no signs of the sensor.
I do some more manual digging, find another manual for the MBE900 that reveals the sensor is built-in to the MCM itself!!!
So...seems I might need a new ECU, I may see if I can still take this one off/apart if I'm feeling brave, or if it's not derating the engine, just live with that code.
Next code: EGR valve not responding. I try to clean the contacts of the plug on the egr valve, didn't help. I do some more digging. I see the service record of this bus had the EGR valve replaced earlier this year. That's odd, I wonder why.
I find more troubleshooting information for that code, and it turns out that code doesn't just mean the valve itself isn't responding, it means the system as a whole isn't detecting exhaust gas flowing through the system, using a combination of the valve info and temperature sensor.
Well I already know the EGR cooler is likely shot, so I'll just replace that cooler and check for blockages later, nothing more I could do that day about it.
Last code: smart switch missing.
This one was the hardest to figure out, it's from the body module, and newer Freightliners have a multiplex wiring system and "smart switches" which is just a fancy switch that defines what it does in the switch itself, not the wiring.
In theory this is cool, you want to move the dome light switch from the left console to the dash? Just move it, plug it into the new plug in the dash, and it will still control the dome lights.
The problem is when a switch goes missing (or wiring problem), the system expects all of the factory installed switches to be present, and it can't find one.
Which one? I've no idea, I don't have the expensive Freightliner software to figure that out, and all the switches are physically present. I checked they are all plugged in, no luck, couldn't clear that code either.
At the end of the day, I used some coat hanger wire to fix the HVAC, and didn't fix anything actually important (the engine codes)...so I feel like I have a long way to go on the road to becoming a competent diesel mechanic
The Windows
...are a big reason I picked this bus. The C2 body has much taller windows, you can see the horizon while standing inside the bus! Plus these were already tinted, black frames, they looked nice.
I was going to reseal them and keep them all in, blocking off the ones I wouldn't use with insulation and interior wall.
I knew that they'd be lacking in insulation, was willing to deal with that with insulated curtains.
Sunday 9-29 my dad offers to help with the bus some, so we plan to remove the interior wall panels. By this point I already know they're going to be epoxied in, but at least with help maybe it won't be so painful.
Once starting to pry on the first panel, we quickly realize the panels are trapped behind the bottom of the windows...so they're going to have to come out. Ok no big deal, was going to remove and reseal them anyway...
You can see there's no framing below the windows. The interior wall is folded back and up again in 2 90 degree angles to form a lower lip for the windows to rest against. Then the interior and exterior panels were bonded together at the edge, which was one of the most tedious to separate without mangling the exterior panels. Fortunately I was able to find a technique fairly quickly that minimized damage greatly, and didn't take too long either.
But the real problem were the windows. The frames on these windows are mostly plastic, and 16 year old dry rotted plastic did not like being removed from the bus. After carefully cutting the caulk(?) around the window and lifting them free, most of them still broke in half, rendering the frames completely trashed.
I have 3-4 unbroken window frames...but that basically made the decision for me that I'm not reusing the original windows.
BTW, the opening is 26" and 5/8 wide by 35" tall. I'd love dual pane windows that can open and bonus if has a screen too...so I'm open to suggestions!
Here's a raw video of removing a single window and panel, so you can suffer along with me if that's what you're into:
https://photos.app.goo.gl/FzeSwC8Y31D7aGgh6
At the end of the day I managed to complete the passenger side windows and walls.
So thanks to working the weekend, my 3 day work was still a 5 day week, but my plan of fully gutting it fell short by still having half the walls to remove, and the entire floor to deal with.
Up next week: gutting completed, measurements, and floor plan...
