Welding/Structural Question

ktmossman · October 03, 2020, 02:05:20 PM

On my J4500 - As I was working my way through a stack of cutting and grinding wheels the other day, I noticed an anomaly in the framing. At the top of the pillars between the three emergency exit windows on each side, I noticed some extra reinforcement. I suspect it has to do with the engineering for these windows openings because the window itself can't be part of the structure like the other windows are.

I'm curious as to whether or not they were factory or added later as part of a service bulletin, because I don't see them referenced in the diagrams/documentation.

Bigger question: There appears to be some cracking in some of the welds. While I have it all exposed, is this something I should reinforce/cleanup? Note: This group of windows is being removed and body panels put in with additional framing.

ktmossman · October 03, 2020, 02:06:22 PM

More pics...

freds · October 04, 2020, 03:20:34 PM

Those welds don't look good; looks like they are already cracking.

Since you have everything opened up, now would be a good time to have it done right.

someguy · October 04, 2020, 06:23:51 PM

I'm looking at J4500s to purchase.

Is there any way to inspect these welds without disassembling the interior ?

chessie4905 · October 04, 2020, 06:37:57 PM

Worry about those cracks after you get one that otherwise suits you. Weld or have it welded after you start the conversion.

ktmossman · October 05, 2020, 08:02:10 AM

Quote from: someguy on October 04, 2020, 06:23:51 PM
I'm looking at J4500s to purchase.

Is there any way to inspect these welds without disassembling the interior ?

No, they are behind the trim...

someguy · October 05, 2020, 11:07:23 AM

How many miles are on your J ?

I'm looking to buy a J. Any advice for me ?

Busted Knuckle · October 05, 2020, 12:32:47 PM

Quote from: someguy on October 05, 2020, 11:07:23 AM
How many miles are on your J ?

I'm looking to buy a J. Any advice for me ?

Yup get your check book out and have fun writing in it!

BK

Jim Blackwood · October 05, 2020, 01:49:34 PM

I think the question must be asked. Do these cracks impact structural integrity? If not, don't worry about them.

Are they addressed in tech service bulletins?
Has MCI taken any action to address them?
Have there been any instances where they have caused any visible evidence of their existence either inside or outside?

It just might be that they aren't really that important.

Jim

ktmossman · October 05, 2020, 02:27:16 PM

The odometer on mine has been zeroed at some point. But, as best we can piece together from the records of the charter firm that owned it, it has around 450K-475K on it (S60/B500).

Advice:

1. Overall, I have been VERY happy with it. I don't have much of a reference point, but the drivers I hired to deliver it LOVED driving it (and they drive coaches of all stripes).
2. Avoid the "gold brick" electronics used in the early models.
3. If you un-plug ANYTHING, label and photograph before disconnecting. (I hired someone to cut out the overhead racks and they ignored my request that they do this. That mistake is about to cost me $$$ to have fixed.)
4. Someday, I want to meet the engineers who designed certain parts of this bus. (And NOT to exchange pleasantries...)
A. The location/installation of the heater core and evap coils of the OTR HVAC. They were designed to NEVER be removed. I cussed more than I ever have in my life. I used to have friends...
B. The lavatory and flush systems. You either remove the exterior body panels, dismantle half the engine compartment, or cut it up into tiny pieces to get it all out. Did some cussing 'bout that, too.
C. The multiplex system in the overhead luggage rack. All of the engine wiring goes through the harnesses in the center tunnel. But, there is a single wiring harness that runs in the overhead rack (driver side.) This would be entirely acceptable, even logical, if this second harness was all related to passenger amenities (lights, AV, etc.). But, NO... In that harness, out of a couple dozen, there is a SINGLE circuit (not marked or terminated any differently) that ties to engine operation. See point 3 above...

someguy · October 07, 2020, 12:18:25 PM

Quote from: ktmossman on October 05, 2020, 02:27:16 PM
The odometer on mine has been zeroed at some point. But, as best we can piece together from the records of the charter firm that owned it, it has around 450K-475K on it (S60/B500).

Good to know. I'm looking at buses with similar mileage. How did you determine that the odometer was replaced ?

Quote
1. Overall, I have been VERY happy with it. I don't have much of a reference point, but the drivers I hired to deliver it LOVED driving it (and they drive coaches of all stripes).

Good to know.

Lots of people recommend older buses and to avoid newer buses due to the more complex electrical systems, but I'm firmly set on a newer one.

Quote
2. Avoid the "gold brick" electronics used in the early models.

I totally agree. This rules out most buses prior to 2003.

Quote
3. If you un-plug ANYTHING, label and photograph before disconnecting. (I hired someone to cut out the overhead racks and they ignored my request that they do this. That mistake is about to cost me $$$ to have fixed.)

And consult schematics before disconnecting so you know what you are doing. And start the bus and ensure functionality before making any disconnects permanent.

Quote
4. Someday, I want to meet the engineers who designed certain parts of this bus. (And NOT to exchange pleasantries...)

LOL.

Quote
A. The location/installation of the heater core and evap coils of the OTR HVAC. They were designed to NEVER be removed. I cussed more than I ever have in my life. I used to have friends...

They must be removable for servicing ? Do you have a shop manual to follow ?

I look forward to hearing about your plans to replace these items.

Quote
C. The multiplex system in the overhead luggage rack. All of the engine wiring goes through the harnesses in the center tunnel. But, there is a single wiring harness that runs in the overhead rack (driver side.) This would be entirely acceptable, even logical, if this second harness was all related to passenger amenities (lights, AV, etc.). But, NO... In that harness, out of a couple dozen, there is a SINGLE circuit (not marked or terminated any differently) that ties to engine operation. See point 3 above...

Thanks for the heads up ! Have you found this circuit in the schematic ?

ktmossman · October 07, 2020, 02:00:41 PM

Either the odometer was changed or I am a lucky SOB that bought a 2006 charter bus with only 35,000 miles on it. And I'm not that lucky...

I have the schematic but, A) it does not use plain English to identify the circuits, and B), the cables in the harness aren't labeled in any way that relates to the schematic. As best I can tell, the circuit in question connects the dash start switch with the rear start switch and the starter.

I am doing mini-splits for HVAC. The space from the AC coils will be the generator bay (and possibly the water heater). The space the heater core was in will hold the fresh water tank.

The struggle getting the AC coils out was largely because the bolts were rusted on the underside of the bus. So, we had to cut all the components out of the casing and then cut the mounting bolts from the inside. On the heater core, I have no clue. There was an access opening to get to the front of it for basic servicing. But I'm pretty sure they built the structure around it. It was simply too large to get through the access space. We had to cut everything off each side of it and then lay it at an angle (VERY difficult because of the weight) to get it though the opening. All while sitting in a bay...

Jim Blackwood · October 07, 2020, 02:16:25 PM

Quote
I totally agree. This rules out most buses prior to 2003.

Actually the mid 90's offer some excellent choices in the D series including the 60 series engine, B500 transmission, r134 refrigerant, and Webasto aux heater. DDEC 4 I believe. Prior to the gold brick.

Jim

someguy · October 07, 2020, 03:42:53 PM

Quote from: ktmossman on October 07, 2020, 02:00:41 PM
Either the odometer was changed or I am a lucky SOB that bought a 2006 charter bus with only 35,000 miles on it. And I'm not that lucky...

OK. Interesting.
Have you queried the ECM to see what it says ?

Quote
I have the schematic but, A) it does not use plain English to identify the circuits, and B), the cables in the harness aren't labeled in any way that relates to the schematic. As best I can tell, the circuit in question connects the dash start switch with the rear start switch and the starter.

Are you referring to the pdf schematic from mcicoach.com or do you have a different one ?

It makes sense that that circuit is run separate and not as part of the multiplex system. Most (all) of the electrical that runs down the center tunnel is either a power feed or communications. I don't think any switch type stuff runs in the tunnel. That is the good part about multiplex buses.

Quote
I am doing mini-splits for HVAC. The space from the AC coils will be the generator bay (and possibly the water heater). The space the heater core was in will hold the fresh water tank.

I await pictures and a write up !

Quote
The struggle getting the AC coils out was largely because the bolts were rusted on the underside of the bus. So, we had to cut all the components out of the casing and then cut the mounting bolts from the inside. On the heater core, I have no clue. There was an access opening to get to the front of it for basic servicing. But I'm pretty sure they built the structure around it. It was simply too large to get through the access space. We had to cut everything off each side of it and then lay it at an angle (VERY difficult because of the weight) to get it though the opening. All while sitting in a bay...

I appreciate the description and heads up. Thanks for sharing.

someguy · October 07, 2020, 04:03:20 PM

Looks like the start circuit for your bus is in schematic 07-14-1282. I assume Multiplex started with #62032 and your bus is between #62032 and #63182 ?

I'm guessing circuit 1161D, 1161C, 1161D or 1161E must run in the overhead baggage compartment ? One of connector P-72, P-33, P-38 or P-42 must be up there ?

Looks like all the buses post gold bricks (#62032) and before diesel particulate filter (#63182) were wired the same.